All Things Car Handling Related

Castor Explained.

In many instances caster is one of the more over looked suspension tuning options on many rc vehicles. But having the correct caster angle can greatly improve your handling performance.

So, what is caster? Caster is the angle of your kingpins or steering blocks when viewed from the side of your car or truck.

If the top of the steering block or kingpin is leaning to towards the rear of your car or truck this is positive caster and if it is leaning forward it is negative caster.

Zero caster is when the kingpins or steering blocks are perpendicular to the ground.

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Now do not get confused if you have done any reading about caster, there seems to be no uniform distinction as to what is negative or positive caster. For this page and any other reference that is make about caster will be uniform.

Positive caster will always refer to the kingpin or steering block leaning back, the top of the kingpin or steering block will be farther towards the rear of your car or truck than the bottom.

This will make negative caster just the opposite the top will lean more towards the front of your car or truck.

Just remember that caster is always determined by viewing your rc vehicle from the side.
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Now for what caster does. Increasing positive caster has many different effects, it slows down steering, increases stability in the corner and improves self-centering.
While negative caster does just the opposite. If you learn anything about caster at all it should be, never bother with any negative caster angles. Negative caster will make your rc vehicle very difficult to drive in a straight line and terrible in the corners.



Let us look closer at how positive caster can affect your rc car or truck's handling.

Less positive caster will give you more off-power steering into the corner, with less on-power steering out of and in a corner. Plus less caster will result in lower straight line stability.

While more positive caster will give you less off-power steering into the corner and more on-power steering in and out of a corner. Also, it will give you more straight line stability.

Now let us look at how to adjust caster. This is getting more complicated all the time. Manufacturers keep refining and adding many more options to adjust caster angles.

On some models it is very easy to accomplish just add or remove shims from the upper or lower suspension arms. Now remember if you move both the bottom and top forward you just changing your wheelbase, making it longer or moving both towards the rear is shortening the wheelbase. If you want more caster either move the top farther towards the rear or the bottom farther forward.

Adding or removing shims as needed. Now remember to adjust both sides the same if you have one side at one setting and the other side at a different setting your car or truck will be almost impossible to drive.

Another way to adjust caster angle on some models is by changing the front hub carriers or steering block. Some models have front hub carriers or steering blocks that have different degrees of caster build into them.

Refer to your owners manual to see which front hub carriers or steering blocks are installed on your rc vehicle and if there are different front hub carriers or steering blocks included with your rc vehicle.

For an added twist to adjusting caster angles is the new adjustable C-hub from Team Xray™. This new style of front hub is going to make adjusting caster much easier. For now Team Xray™ has a patent on this design and are the only ones to offer it. I do feel that in the near future you will see this options on many others models also.

There is one added twist to adding more positive caster to your front tires. This has to do with your outside tire in a turn.

As you increase steering input in a corner this will increase the negative camber on that tire. To take advantage of this all you need to do is lessen the static negative camber on you front wheels.

To see if you have set your caster/camber relationship correctly is to look at your front tire wear. If the inside of your front tires are showing more wear than the outside you need more camber and if the outside is wearing more you need less camber.

For maximum traction you want your front tires to wear evenly.

When is it time to change your caster settings? Is your rc car or truck feeling a little twitchy or a little too aggressive on turn-in in a corner?

Adding more caster will slow down how quick your car or truck turns. This may cause you to have to add more steering input with your radio to get your car or truck to turn the same as before.

On the other hand if your car or truck feels sluggish in corners lees caster is needed to give you a snappier feel.

Do remember when you make any changes to caster that it is going to make big changes in the handling and performance of your car or truck. This change could be for the better or worse.

With almost all caster adjustments being either 2° or 3° of change, only use caster adjustments when big changes are needed in the handling of your rc vehicle.

Also, remember that any time you change caster you will need to fine tune many other aspects of your suspension.

If you do change your caster keep good notes on what you did, just in case it does not work, so you can go back to your old settings and then try something different.

Keeping notes or setup sheets on all your suspension changes is a very important part of getting your rc car or truck's handling dialed-in.

The last thing to remember about caster is the only way to measure the degree of caster accurately is with a setup station. But, do not worry if you do not have or do not want to get a setup station, almost all caster settings and changes are done in either 2 or 3 degree increments.

Getting the camber adjusted or tuned correctly is one of the first and easiest adjustments you can make to your rc vehicle.

What is camber? Camber is the vertical angle of your tires. When you look at the front or rear of you car or truck are the top tires leaning towards or away from the chassis.

If the top of a tire is leaning towards the chassis this is negative camber and if it is leaning away it is positive camber.

What camber does to your handling. To start off let us look at what incorrect camber angles will do to your handling. It affects overall traction, cornering ability and handling.

With camber angles not adjusted to both track conditions and your driving style can make driving or racing your car or truck very frustrating.

Now let us look at why camber angles are so important. When you enter a corner your car or truck will want to lean, because of the force of gravity.

The faster or harder you enter a corner the more lean you will have. This flex of the suspension will cause the inside tires to want to lift off the surface and the outer tires to lean away from the chassis.

This changes the contact patch of the tires, the area of the tire in contact with the surface. If camber angle is incorrectly set the contact patch lessens causing the loose of traction.

On the other hand, with camber angles set correctly the contact patch remains flat, lessening chassis roll then increasing traction.

Now let us look at how to adjust camber. Almost all rc vehicles use turnbuckles to adjust camber. These turnbuckles, in most cases, are threaded in opposite directions with hex nuts mounted in the center of the turnbuckle.

When installing camber turnbuckles make certain that they are all installed the same way. This will make adjusting camber much easier and faster if all turnbuckles turn in the same direction to shorten or lengthen.



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To make installing or adjusting new turnbuckles easier put a little white grease on the threaded ends of the turnbuckle. If you are putting together a kit, just add the grease before installing the turnbuckles the first time. If your new vehicle is a RTR or ARR just unthread the turnbuckles and add grease to the threads and reinstall. This will make installing and future adjustments much easier and less frustrating.
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The tools needed for adjusting camber. A camber gauge by RPM Products works great or a setup station by either Hudy or Team Integy also work great.
Plus, these setup stations help with many other setup options. Also needed is a turnbuckle wrench or pliers.

At what camber angle should my rc vehicle be set at? Camber angles for on-road and off-road serve different purposes, but there is some common ground between them.

Let us first look at rear camber, it is a little more straight forward. As a general rule rear camber will be set somewhere between -.2° to -.5° will be more than enough to counteract chassis roll.

When it comes to the front camber settings can get a little more complicated. When setting camber on the front caster also comes into play.

Caster is the angle of the kingpins or steering blocks when you are looking at it from the side. Generally when high degrees of caster are used less camber angle is needed and the when less caster is used more camber angle is needed.

Refer to your owners manual to help determine what camber angles are the best for your rc car or truck.

Also check race setup sheets for different conditions to help find what camber angle best suits your conditions or driving style.

One other item comes into play when adjusting camber angle and that is the angle of the camber link. Almost all rc vehicles have the option of changing the angle of the camber link.

This angle is changed by moving the camber links to different mounting holes on the shock towers.

Again refer to your manual to see how your rc truck or car reacts to changing the camber angle. Plus this is a very easy adjustment so it is easy to play around with.

Change the angle of the camber link and see how it affects your car or truck's handling.

As a general rule the higher the camber link is mounted the more on-power steering you will have. Plus the car or truck will respond slower to your input. This works better on smooth, high grip tracks with long fast corners.

When you mount the camber link in the lower mounting position will result in less on-power steering. Plus,it will respond quicker to your input. Best to use on tracks that have quick fast direction changes.

Again refer to your owners manual to see how your rc car or truck is designed to handle camber link angle changes.

The last thing to keep in mind is the length of the camber link. On many rc vehicles you have the option of mounting the camber link in either a short or long length.

In most cases the shorter camber link length will give you more camber gain, slightly more traction and less steering and stability.

While longer camber link length will result in less camber gain, more stability and it will respond to input slower.

Again refer to your owners manual to see just how your vehicle reacts to changing the length of the camber link.

In my opinion the most important thing about doing any tuning on your suspension is keeping notes as to what you have changed.

Plus, until you fulling understand how you rc truck or car reacts to each different tuning option, just change one thing at a time, then run your rc vehicle to see just how it reacts and make note of the change.

Doing your suspension tuning in a slow step by step process before you know it you will turn into a suspension tuning guru.

Toe in or out refers to the horizontal angle of your tires. If leading edge of your rc tires are pointing in, when you look down at them from above, this is toe in.
If they happen to be pointing out this is toe out. Toe most generally affects both your turn-in ability on corners and straight line driving.

If you have the toe angle set properly straight line driving and cornering will be much easier. Learning how to set the toe angle on your rc car or truck will help you get the most out of your suspension.

You must have the toe set the same on both sides of your rc vehicle or your handling will be very unpredictable.

If you do have the toe angles set differently it can cause your car or truck to veer off unexpectedly, it will be difficult to get it to corner with any kind of rhythm, plus it will be impossible to drive it in a straight line.

So, understanding toe angles and how to set the toe angle on your car or truck is very important.

What toe in or toe out should your car or truck be set at?
On-road and off-road vehicles react differently to toe angle, plus track conditions also play a big part to what toe angle is the best.

Front toe in will generally result in increased stability on the straight aways, but it will increase drag.

Toe out on the front improves cornering ability, but can make your vehicle twitchy on the straights.

On the rear the only vehicles that use or consider toe-out are rock crawlers, this helps the crawler's rear end swing around corners and turns.

Rear toe in on all other vehicles helps to counteract over steer, improve off power steering and increase traction.

As a general rule of thumb, one to two degrees of toe in or toe out is all that you will want.
To adjust toe angle on the front of your car or truck will either be done by adjusting the turnbuckles or tie rod ends.

Adjusting rear toe angle is a little more complicated, because most all are fixed. With the rear being fixed it will require you change wheel hub carriers or bulk heads.

There are always a few exceptions, a few vehicles do use turnbuckles in the rear to adjust toe angle.

I am sure you are now wondering how do I check or measure the toe angle on my vehicle.
There are many different tools available to you to accomplish this task. Hudy and Team Integy both build setup stations for many different size vehicles that will make measuring and setting toe easy.

These setup stations and gauges can be expensive, so if you are on a tight budget there is away to build your own toe angle gauge.

To build your own toe angle gauge, you will need a piece of construction paper that is bigger than your rc truck or car. Plus you will need a ruler, pencil and protractor. I do hope that you remember a little from your Geometry class.

To start off place your rc truck or car on the construction paper, as straight as possible. Now you will need to draw a line that is perpendicular (right angle or 90°) to the leading edge of your paper along side your tires the length of the vehicle. Do this on both sides of your car or truck.

This may take practice and patience.

It is very important that these lines be both perpendicular to the leading edge of you paper and that they are parallel. Also, these lines need to be at the same distance to the tire. Now line up your protractor with a tire and read the angle relative to your straight line. That angle is your toe angle, either in or out. Now work you away around you car or truck checking each tire.

It is essential that you fronts and rears be at the same angle from side to side.

Once you have you toe angles set, this is one part of your vehicle's setup that crucial for better handling.

Once you master this way of checking and setting toe angle it will become easier, so you can check your toe on a regular basis.

Every once in a while check your toe angles to make sure nothing has been knocked out of whack or dent.

What is the purpose of sway bars? They tie the left side wheels to the right side wheels on both the front and rear of your rc truck or car.
What do they do: In a corner your rc vehicle wants to roll over in the corner due to centrifugal force.

With out sway bars on an off-road vehicle this causes excess chassis roll that compresses the outside suspension and tire and causes the inside tire to go into droop.

While on an on-road car this excess chassis roll overloads the outside tire and unloads the inside tire lowering overall traction.

With a sway bar in a corner your off-road vehicle still wants to roll over, but with both sides being tied together your suspension reacts differently.
As your outside suspension and tire compress your inside no longer goes into droop. The sway bar raises the inside suspension arm raising the inside tire.

This lowers your center of gravity causing your rc car or truck to settle down in corner and be more stable.

While on a on-road rc car a sway bar accomplishes the same thing, but the big difference is that it keeps both the inside and outside tires planted squarely on the ground increasing traction.

There is two types of sway bars either a formed wire or flat blade. The formed wire sway bar is the most common and it is the only sway bar you will find on an off-road car or truck, plus it is also common on some rc touring cars.
While the blade type sway bar is most common on rc on-road cars.

The formed wire type sway bars works by twisting, thus providing a spring action as it untwists. The blade type sway bar works by bending or flexing into a U-shape to produce its spring action. It is most common on touring cars as to keep their center gravity as low as possible.

As to the size of sway bar be it either the wire or blade has the same effect. A lighter or thinner sway bar will reduce the effect of the sway bar, while a heavier sway bar will increase the effect of the sway bar.

The weight of your rc car or truck also determines the size of sway bar you need to run. A heavy rc monster truck with heavy large tires will need a large heavy sway bar. While a small light weight on-road car will need a much smaller lighter one.
Also to keep in mind with learning how to adjust and tune your sway bars is your setup and driving style. You may want to run different size sway bars on the front and rear. There is no carved in stone rules when it comes to sway bar adjustment. It all depends on your conditions and driving style.

Keep in mind that your sway bars do not work by themselves. The effectiveness of the sway bar you run depends also on the weight of spring you run.
With the sway bar tying both the left and right side together, the sway bar must overcome the weight of the spring on the opposite side as one side compresses.

If a light weight thin sway bar is used this allows a lot of movement on the outside suspension arms and very little on the inside suspension arms in a corner.

While a thick heavy weight sway bar so stiffly connects both sides of your suspension resulting in what feels like a straight axle suspension.

The trick is finding the sweet spot between these two extremes. Sway bars do not change the overall traction of your rc car or truck, they just affect your side grip in a corner.

Besides springs chassis flex plays an important role in the effectiveness of your sway bars. The stiffer your chassis is the more responsive your car or truck will be to nay changes to sway bar settings.

Adjusting sway bars is a balancing act, increase stiffness to a sway bar on one end, reduces the side grip of that axle, while increasing the side grip on the other end. The net effect of sway bars on both on-road and off-road vehicles is almost the same.


A softer front bar:
1. Increases front chassis roll.
2. Increases front grip or traction, while decreasing rear grip or traction.
3. Slower steering response.
4. Increases off-power steering at corner entry.


A stiffer front bar:
1. Decreases front chassis roll.
2. Decreases front grip or traction, while increasing rear grip or traction.
3. Faster steering response.
4. Decreases off-power steering at corner entry.


A softer rear bar:
1. Increases rear chassis roll
2. Increases rear grip or traction, while decreasing front grip or traction.
3. Less on-power steering.


A stiffer rear bar:
1. Decreases rear chassis roll.
2. Decreases rear traction, while increasing front grip or traction.
3. Faster steering response in high speed corners and chicanes.
4. Increases on-power steering.

For on-road or touring cars the results of adjusting sway bars can quickly be seen. The easiest way to see if you are running the correct sway bars is tire wear.

Your goal is to get the front and rear tires to wear the same.

Also, if your touring car does not want to turn or pushes into the corners a smaller front sway bar could help.

Plus, if your touring car is turning too good or wants to spin out on corner entry a larger front sway bar can help correct this.

As for adjusting or tuning them on off-road vehicles it is not so straight forward. You need some chassis roll to help plant the outside tires in a corner, while at the same time you do not want too much to cause a roll-over.

It is a fine line and depends on your driving style and conditions.

Also your center of gravity comes into play with off-road vehicles the higher your center of gravity is the stiffer sway bar you are going to need.

This will cause your monster truck to squat more in the corners lowering its center of gravity.

With tying both sides of your suspension together it does have some drawbacks.

On a rough track and using stiff or heavy sway bar can have negative results to both off-road and on-road cars and trucks. Hit a rut or bump with one wheel will upset the suspension on the other side of the vehicle. This can cause small bumps and ruts to seem much bigger than they are.

So, if you are running on a bumpy or rough track try using a smaller or lighter sway bars.

The last thing to remember about sway bars is no one setting is going to work for every situation or driving style.

Want works for you more than likely not work for someone else and vice versa.

Learning how to master adjusting and tuning sway bars can and will improve both handling and performance.

Wondering how shock angle or position is going to effect the handling or performance of your rc vehicle? What are all those holes on my shock tower and suspension lower control arm for?
Let us see if we can get shock angle all figured out and explained!

First let us look at the lower control arm. On many rc cars and trucks there is two, three or four different shock mounting points on the lower control arm.

These mounting points will either move the shock closer to the center of the vehicle or closer to the wheel.

The most important thing about understanding shock angle is to first understand how your suspension works.

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This look at shock angle or position is going to be about the standard setup. With the upper end of the shock mounted to a shock tower and the lower end mounted to the lower suspension arm. This information may some what apply to the cantilever-style suspension, like on a Traxxas™ Revo® or an Ofna Racing™ DM-One®, that have their shocks mounted horizontally mounted, but not totally.
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What trying to understand or master rc suspension tuning the most important thing you need to know is how this adjustment is going to affect the wheel and how it contacts the surface.
The purpose of any adjustment, no matter what it is, is too maximize all four tires and their ability to maintain traction on any given surface.

Understanding shock angle and shock mounting location is helpful, because both have an influence on how much down pressure the spring and shock apply to the tire.

On the standard vertical mount shock system, the inside of the lower suspension arm is mount to the chassis with a hinge pin. This is the pivot point of the suspension arm.
While the outside of suspension arm is where the tire is mounted and this is the location of the input force (ruts, bumps, jumps or any other obstacle).

While where the shock mounts to the lower suspension arm is the point of resistance.

With the pivot point and input force locations fixed the only variable point is the mounting locations. Either closer to the tire or closer to the chassis on either the shock tower or lower suspension arm or both.

On many rc vehicles you have the option of moving both the top and bottom closer to the tire or chassis or moving one end closer to the chassis and the end closer to the tire or vice versa.


To get started let us first look at moving shocks laterally, Moving both the top and bottom of the shock either closer to the tire or closer to the chassis.

When you move both the top and bottom of the shock closer to the tire this gains a more direct relationship between the tire movement and the amount of shock piston movement.

Example, if the tire moves a half inch the piston of the shock moves close to a half inch. This results in your spring feeling slightly stiffer and shock oil slightly thicker.

Now what happens when you move both the top and bottom of the shock closer to the chassis. Now the lower suspension arm moves considerably more than the shock piston.

When the tire moves a half inch the shock piston moves much less than a half inch. This results in your spring feeling softer and shock oil slightly thinner. Giving you a "plusher" ride, but more chassis roll.

Moving the shocks inward allows for more suspension travel without bottoming out the shocks or pulling out the piston shafts.

Now let us look at moving the ends of the shock in different directions to increase shock angle or what is called " laying the shock down" or "standing the shock up".

As you lay the shock down or increase the shock angle the more progressive your shock is going to feel. Meaning your suspension is going to feel softer on the small jumps, bumps and ruts, while feeling stiffer on bigger jumps, bumps and ruts.

This progressive feeling is accomplished by the arc of the suspension arm. As the lower suspension arm compresses shock compression increases and the lower mounting point moves inward.

With a shock in the laid down position, it is compressed much less in the early stages of suspension travel and is compressed much more in later stages of travel.

A laid down shock will result in a plusher feel, while maintaining good traction over small bumps and ruts and helps to reduce body roll.

The net effect of shock angle is:
The more inclined shock angle, moving the top closer to the chassis and/or moving the bottom closer to the tire:
1. Softer initial shock damping.
2. More progressive damping.
3. Improved lateral traction.
4. Handling will be more forgiving.
5. Good for high traction or bite tracks, will it making your rc car or truck more stable.


The less inclined shock angle, standing up the shock, moving the top closer to the tire and/or bottom closer to the chassis:
1. Stiffer initial shock damping.
2. Lowering lateral traction.
3. Makes your rc car or truck more responsive.
4. Can make your car or truck have a more direct feel.
5. Can be best suited for tight, technical tracks with many low speed corners.

The last thing you need to remember about changing shock angle is that it is a subtle change. It can be very affective when one spring feels too stiff and the other too soft. It is one of the last things you need to do when tuning in your suspension.

One parting thought, the upper and lower mounting holes that are found on many shock towers are for raising or lowering ride height.

Again, these are just subtle ride height changes and come in handy if a small ride height change is needed.

Understanding spring weight or stiffness and spring preload can be very confusing. For that matter any rc suspension tuning can get very confusing.

Because changing one thing alters many different aspects of your suspension and performance. Keeping it all straight is difficult.

I find it much easier if I assign specific function to each different suspension function.

For example I control chassis roll with ride height and chassis bottoming out to shock damping with either shock pistons or shock oil viscosity.

This leaves maximizing traction to the springs and spring preload.

You do not need to copy my system, just come up with one that suits you and your driving style.

The only thing to keep in mind is what ever system you use to control and adjust every aspect of your rc suspension is that you stay consistent.

That way if you want to change "X" you adjust "Y". "X" being chassis roll, bottoming out, pushing in the corner and etc... With "Y" being shock angle, spring weight or spring preload, wheelbase and etc...

Coming up with your own system is going to take time and some trial and error. This is where setup sheets come in very handy.

I has amazed me just how much better my handling and performance has got since I have assigned a function to each of the different aspects of rc suspension tuning.

Plus, it is much easier and faster to make a change when I know what to change.

Now let us take a closer look at spring weight and spring preload to maximize traction.

You goal is to get the same about of down pressure on all tires or the same on both front tires and the same down pressure on both rear tires.

The best technique to balance down pressure is by the use of a scales. To get your rc vehicle balanced is to have the same weight on all four tires or depending on your setup the same weight on the two front tires and the same on the rear tires.

With using shock damping to maintain ride height, you are going to want to use the softest spring as possible and with adding preload (amount of spring compression) to your springs to maintain this static ride height.
Why not a stiffer spring? A stiffer spring will not compress any at static ride height. This will result in your spring having little or no effect on your suspension when it goes into droop.

Droop is the amount of down travel above ride height. A soft spring with a lot of preload will extend your suspension downward when you are going over ruts, bumps and jumps.

This will make your rc vehicle more stable when it is going through these sections.

Plus, with a lot of preload will help with the launch off of jumps, causing you to fly higher and farther, to clear that big triple.

Using softer springs will give your rc vehicle the ability to absorb those bumps, ruts and potholes while maintaining traction.

Your ultimate goal to always maintain maximum traction.

Is your rc vehicle pushing or tight in a corner? Do you have under or over steer? Changing the spring or preload bias toward the front or rear can help correct these problems.

Soften the front spring or reduce preload will result in your front tires sticking better in the corner for an example.

The results to spring preload is:
1. Less preload your suspension will have less droop and down travel.
2. More preload will add more droop and suspension down travel.

How a softer spring affects handling:
1. Increases chassis roll.
2. Better traction.
3. Increase the chance of bottoming out on landing after jumps.
4. Better for bumpy tracks.
5. Better on large open tracks.


How stiffer springs affect handling:
1. Reduces chassis roll.
2. Reduces traction.
3. Reduces the chance of bottoming out after jumps.
4. Your car or truck will react faster to steering inputs.
5. Better on smooth tracks.
6. Better on tight smooth tracks.


How softer front springs affect handling:
1. Adds more steering mid corner and at corner exit.
2. Can result in under steer during braking.


How stiffer front springs affect handling:
1. Increases mid corner and corner exit under steer.
2. Reduces under steer during braking.
3. Increases your rc vehicle responsiveness, but will make it more "nervous".


How softer rear springs affect handling:
1. Increases forward traction.
2. Improves side traction mid corner.
3. Good through bumpy sections.

With the knowledge you are gaining, all you need to do is apply it.

Learn to read your track, is it blue grooved, loose and dusty, full of ruts and potholes, big jumps or tight and fast.

With a few test runs you will know what adjustments if any you a going to need to make. As your knowledge and experience grows you will be able to make many of these adjustments before you get on the track.

Always remember this hobby is about having FUN. Plus, remember to help the new guy, help to make this hobby fun for all involved.

There is two components of shock damping, shock pistons and shock oil.

Like all other aspects of rc suspension tuning any changes to the shocks is going to have an affect on all other aspects of how your suspension works, it could have subtle or an extreme effect on handling and performance.

Do you have your rc vehicle handling good, but are you looking to get just a little more performance? Changing your shock damping, by either changing shock pistons or oil could give you that little edge.

To understand shock damping you first need to understand just how a shock works. The basic purpose of your shocks is to take the bounce out of your springs. This is accomplished by the size of holes in your shock pistons and the viscosity (weight) of your shock oil.

Let first take a look at the shock pistons and exactly what they do. The shock piston is attached to the end of your shock shaft inside your shock body. The shock piston is a flat round disk with holes in it.

The entire outer edge of the shock piston comes in contact with the inside edge of the shock body. The piston is a restrictor or dam that only lets the shock oil to past through it at a certain rate depending on the size of the holes or the viscosity of the oil.

The smaller the holes the more restriction and like wise the larger the holes the less restriction. This restriction happens on both compression and decompression of your rc suspension.

Compression being when your rc vehicle hits a dump or landing after a jump. Decompression is when your springs want to return your rc vehicle to ride height after the bump or jump.

Shock damping is the speed at which this happens, small piston holes will be slower and large piston holes will be faster.

As the shock piston moves inside your shock body oil passes through the piston. When the shock piston reaches a certain speed oil will start to backup behind the piston, this is called "packing up". As the shock packs up it acts like it is locked up. This is what keeps you from bottoming out after the big jump.
If your track has a lot of jumps or a big jump with a small landing area try using smaller holed pistons. This will keep your rc vehicle from bottoming out after the jump. Also it will keep your suspension working will over the small stuff, but your shocks will pack up on the big stuff. Using smaller holed pistons is also helpful on low-bite tracks, it is going to be helpful through the rough stuff, helping to maintain maximum traction.

If you are running on a high-bite track you may want to use a bigger holed piston. This will allow your rc vehicle to bottom out after that big jump to scrub off some speed to get into that corner that is directly ahead.

One last thing to keep in mind about shock pistons is the type of hole. There are two different types of holes in shock pistons, straight and tapered.
A straight holed piston is going to allow for the same damping on both compression and decompression or rebound.

A piston with a tapered hole is going to compress and rebound differently. With the taper up your shock is going to have less damping on compression, with more damping on rebound. Just the opposite is going to take place with the taper pointing down, more damping on compression and less damping on rebound.

How a tapered shock piston performs or when and where to use them is up to your driving style. This is one area of rc suspension tuning that depends on your driving style and the performance you want out of your rc vehicle.

For an example, if you want your shocks to pack up quickly, so you will not bottom out after that big jump, but return to ride height a fast as possible. You may want a tapered piston, with the large part of the taper pointing down. This will make your shock act like it has heavier oil on compression and lighter oil on rebound.

Using shock pistons to control when your shock packs up. You can use shock oil to control just how fast your shock is going to move.

A lighter viscosity oil is going to let your shock move faster, while a heavier viscosity oil is going to slow down your shock movement.

If your track is smooth, with lots of traction, big sweeping corners, with no or one big jump you may want to consider shocks with big holed pistons and heavy oil. This will allow you to blast into the corners letting your rc vehicle just take a set. Your shocks will react slowly transferring weight slowly through the corner.

On the other hand if your track is bumpy, with little or no traction, tight corners and a load of jumps and dumps. You may consider a smaller holed piston with lighter oil. This allows your shocks to react quickly, to transfer weight when needed and maximize traction.

Finding the right combination of shock damping can be tricky and it depends a lot on your driving style. So, finding the combination of shock piston and oil weight to achieve the shock damping you want takes patience and practice.

Keep notes and or setup sheets so you will know how each combination works for you.

The net effect of shock piston hole size and oil viscosity on shock damping:

Shock oil:
1. Lighter is the same as larger piston holes.
2. Heavier is the same as smaller piston holes.


Shock piston hole size:

Smaller:
1. Stiffer damping.
2. Slower weight transfer.
3. Vehicle reacts slower to input.
4. Reduced chance of bottoming out, when combined with heavier weight oil.
5. Less chassis roll, when used with heavier oil.
6. Use with lighter weight oil on a rough track.


Bigger:
1. Softer damping.
2. Increased traction.
3. Faster weight transfer.
4. Vehicle reacts faster to input.
5. An increased chance of bottoming out, when used with lighter weight oil.
6. More chassis roll, when used with lighter oil.
7. Use with heavier oil on smooth tracks.



When you do any shock damping changes, shock rebuilding or spring changes you are going to want to have your shocks matched.
So both sides of your rc suspension react the same you are going to want your front and rear shocks to be the same length, compress and decompress at the same rate. Team Losi™ makes a great shock matching tool.

With matching your shocks your rc vehicle is going to react the same in both left and right corners. With having your fronts matched and rears matched your reaction to bumps, ruts and jumps is going to be the same.

With your shock matched you could easily add that little advantage you are looking for.


One last thought about shock damping, as you are expermenting do not make wholesale changes.

Just change one thing at a time, piston hole size or oil viscosity and see how that changes your performance. Then if you feel that your shock damping is still not right and you are still looking for better performance then try the other.

Learning rc suspension tuning and how shock damping affects performance is not an easy task. It takes a lot of patience and practice. It can be one of the most enjoyable or hated parts of this hobby, depending on how you go at it.

Some of the changes you make are not going to be that "miracle cure", they could lead to your rc vehicle handling like so much "junk". If that happens at least you know what doesn't work.

Now you know what not to do and are closer to finding what does.

Doing any rc suspension tuning by using ride height is very specific to the type of rc vehicle you have.
Ride height on a on-road car is very different to the needs on a off-road vehicle. For on-road applications be it asphalt or carpet you are going to what your ride height as low as possible to balance downforce equally on all four corners.

Your objective with an on-road vehicle is to reduce chassis roll for very fast cornering.

But, get in the dirt everything changes and ride height changes are needed for the many different surfaces and conditions you have to race on. So for this page all the pointers on ride height will deal with off-road conditions.

What is ride height? Ride height is the distance between the bottom of your chassis and the ground when your rc vehicle is setting still.

So, besides the obvious reason for changing ride height, that being ground clearance what does ride height do.


Changing ride height alters how your rc vehicle transfers weight in the corners and how your rc off-road vehicle handles the bumps, jumps and ruts on the race track.

Increasing ride height will increase chassis roll, while lowering ride height decreases chassis roll.

How do you change ride height? On almost all off-road rc vehicles you have many options when it comes to changing ride height.

You can change the shock mounting position, change the spring pre-load or change springs either stiffer or softer, to arrive at the desired height.

How ride height affects handling and performance. With ride height being one of the easiest adjustments you can make, it can often turn out to be one of the most used.
So, understanding how it can affect handling is important. One of the major reasons for changing ride height is the amount of traction a surface has to offer.

On a low-bite track you are going to want more traction with increased weight transfer, so you are going to want a higher ride height.

Then for a high-bite track you will require less traction with less weight transfer, so a lower ride height is needed.

Do remember than any changes to ride height can and does affect droop, the travel above ride height. This also goes for any change you make on your suspension, one change will affect something else.

So it is very important to find a balance and try to keep your rc vehicle in balance.

Another thing to keep in mind about ride height is that you do not need to run the same height on the front and rear.
Having the front lower or higher than the rear and vice versa can greatly improve your handling.

If you are having problems with the rear tires spinning and causing your vehicle to want to spin out. Try raising the rear higher than the front. This helps the rear tires get more traction than the front helping your rc vehicle settle down.

If you are running on a track that has high traction and your vehicle does not want to turn. Try raising the front higher than the rear. This can be done by either raising the front or lowering the rear. This will add more traction to the front tires making it easier to turn.

If you are having handling problems try changing ride height first to see if that improves handling and performance.

With it being so easy and quick to do, changing ride height can sometimes be the only chassis and suspension adjustment that you will need to improve handling.

Droop, as defined by Webster's Dictionary is "to sink, hang or bend down or to lose vitality or to become dejected".

But in the world of rc cars and trucks it means something else entirely. For us it referrers to the amount of down travel or travel above ride height our suspension has.

In learning about rc car suspension tuning droop is another of the key elements of getting your suspension perform just the way you want.

Having your droop set correctly will help you over those bumps, ruts, holes, uneven spots, through corners, braking and acceleration.

Droop's main objective is to help with weight transfer like sway bars. While sway bars only transfer weight from one tire to the opposite tire relative to the amount of load on a given tire. This weight transfer is only left to right or right to left not front to rear.

While droop aids with weight transfer from front to rear and vice versa to maximize traction over the rough stuff and with on-power and off-power steering. With droop having an effect on side to side and end to end weight transfer, it has more of a 360° effect.

Droop has a bigger effect on rc on-road cars then rc off-road cars and trucks.
But droop is still important on off-road vehicles.

The thing to remember about droop on an off-road vehicle is when you are setting ride height.

If you set your ride height too high, you maybe alright on jumps, but you could be hurting performance through ruts, holes and other rough stuff.

Getting droop set correctly on an on-road car is more critical.

It plays an important role in maintaining maximum traction on acceleration, cornering both on-power and off-power, and chassis roll.

As a general rule the effect of different droop settings is relative same for both on-road and off-road rc vehicles.


Net effect of less front droop:
1. Reduces front chassis upward travel on acceleration.
2. Improves high speed steering ability.
3. Increases on-throttle understeer.
4. Better on high speed smooth tracks.


Net effect of more front droop:
1. Increases front chassis upward travel on acceleration.
2. Reduces high speed steering ability.
3. Reduces on-throttle understeer.
4. Better on tracks that are rough with ruts, bumps, holes and jumps.


Net effect of less rear droop.
1. Reduces rear chassis upward travel under braking or off-throttle.
2. Improves stability under braking.
3. Better on high speed smooth tracks.


Net effect of more rear droop.
1. Increases rear chassis upward travel under braking or off-throttle.
2. Improves steering in slow corners.
3. Better on tracks that are rough with ruts, bumps, holes and jumps.


A reference guide for different droop settings.
1. Need to reduce off-throttle steering - Reduce rear droop.
2. Need to improve off-throttle steering - Increase rear droop.
3. Need to reduce on-throttle steering - Increase front droop.
4. Need to improve on-throttle steering - Reduce front droop.

Are you running on a smooth, high-bite track - Reduce droop on all four corners. - Keep your rc vehicle flatter.

Are you running on a bumpy, loose track - Increase droop on all four corners. - Let your rc vehicle roll more.

The principle of Ackerman Steering is the relationship between the front inside tire and front outside tire in a corner or curve.

It is the term used to define the steering geometry where the inside tire needs to turn tighter than the outside tire. This allows both tires to roll around a common point in a corner or curve. This can greatly improve cornering ability and performance. When doing any rc suspension tuning it should be one more thing to consider.

Rudolf Ackerman discovered and defined this principle early in the 19th century. Since then Ackerman Steering has had a huge impact on many different vehicles.

Ackerman Steering is used on all sizes of vehicles from full size down to scale models, no matter if it is 2wd or 4wd.

Some refer to Ackerman as the degree of toe-in or toe-out a wheel or tire has. Ackerman does have a relationship with the amount of toe-in or toe-out on your rc vehicle.

But, Ackerman Steering deals with the angle of inside tire and outside tire in a corner or curve relative to the degree of toe-in or toe-out. Will that is about as clear as mud. Let see if we can clear it all up.

In all the examples and photos below are for explanation purposes only.

Their only purpose is to explain the general principles of both parallel arm steering and Ackerman steering.

With the suspension on almost all rc vehicles being very complex it is impossible to give exact setting as to toe-in or toe-out and any Ackerman setting.

With so many factors, surface, tires, 2wd or 4wd, degree of toe-in or toe-out, driving style, etc..., that come into play it is up to you to find just what settings work the best for you.

But, understanding the principles can make it much easier to find the combination that works the best for you.

First let us look at parallel steering arms: Referring to the photo on the right:
With parallel steering arms, the steering arms are parallel to the sides of the rc vehicle.

With any steering input both front tires will move an equal amount. This will cause the inside tire to slide or "scrub" through the corner or curve. With the inside tire scrubbing in a curve has many ill effects, heat build up, excess tire wear and traction loss.

This will result in your cornering ability to be twitchy and unpredictable. If you are using a parallel steering arm setup you can play with toe-in and toe-out to help to eliminate this problem, but it will always be present.

The best you can do is find a setting that works for you. With the front tires always turning equal amounts you just have to learn to live with your inside front tire scrubbing in a corner. No way around it.

Now the effects of angled or Ackerman Steering: Referring to the photo on the right.
With your steering arm angled towards the center of your rc vehicle will result in your tires angling at different degrees in a corner or curve.

Using Ackerman Steering your inside tire will be angled more in a corner than your outside tire.

With your inside tire needing to follow a smaller arch than your outside tire, this difference in angle will reduce or eliminate scrubbing. As you enter more steering input increases this difference in angles. More angle to the inside tire than the outside tire.

Referring to the photo on the right, shows this difference in tire angle.
This example is just that, the amount of travel of your front tires depends on the steering geometry of your rc vehicle.

The amount of travel will vary depending on many different things, servos, steering arm lengths, tire size, type of front hubs, type of control arms, and etc...

Now let us look at Ackerman Angle: Regarding rc vehicles Ackerman Angle is referred to True, More or Less.

True Ackerman angle is when a line drawn from the center both king pins or pillow balls through the steering arm mounting points intersect on the center line of the rear axle.

More Ackerman Angle is when these lines intersect in front of the rear center line.

While less Ackerman Angle results in these lines intersecting behind the center line of the rear axle.

When you combine toe angle and Ackerman Angle together you can get some interesting results.

First off let us look at True Ackerman and different toe angles:
1. Zero toe (wheels pointing straight ahead) and True Ackerman will result with both tires being aligned with the circumference of the circle or arch of corner. Refer to the photos on the right.

2. With toe angle set to out and True Ackerman will result with both tires being toed-out equally relative to the circular path that they are following. Refer to photos on the left.

3. With toe angle set to in and True Ackerman will result with both tires being toed-in equally relative to the circular path that they are following. Refer to photos on the right.

Next let us look at Less Ackerman and the different toe angles:

1. With toe angle set to in and Less Ackerman will result with a small angular inequality between the front tires. The inside tire will be trying to follow a larger circle or curve than it actually does. Toe in on the front inside tire. Refer to photos on the left.

2. With Toe set to out and Less Ackerman will result in with the outside tire being toed-out and the inside tire would be running parallel to the circular path it is following. Refer to photos on the right.

Last let us look at More Ackerman and the different toe angles:
1. With toe angle set to in and More Ackerman will result with the outside tire being toed-in relative to the circular path and the inside tire running parallel to the circular path they are following. Refer to photos on the left.

2. With toe angle set to out and More Ackerman will result with the a larger inequality between the turned front tires. The outside tire will be running parallel with the circular path they are following, with the inside tire trying to follow a smaller circle than it actually is. Refer to photos on the right.

Learning and understanding Ackerman Steering and Angles is complex. You will need to do some testing with different Ackerman settings and toe angle to see what works the best for you.
There are no carved in stone rules as to which settings you need to use for what conditions. A lot depends on your driving style, tires and many other suspension settings.

As a general rule Ackerman Angles will have these net effects:

More Ackerman
1. Steering response will be smoother.
2. Your rc vehicle will react smoothly to any steering input.

Less Ackerman
1. Initial steering response will be more direct.
2. Your rc vehicle will react faster to any steering input.

If you are running a parallel steering arm setup in your rc vehicle and are looking for better handling and performance, you should consider changing over to Ackerman Steering.

With the number of adjustments that Ackerman Steering offers it can make huge improvements in your handling.

Almost all manufacturers offer Ackerman Steering as a hop-up option for many of their rc vehicles.

Anti-squat refers to the angle of the lower rear control arms when looking at your chassis from the side.

Even more exactly the angle of the rear hinge pins.

If they are angled rearward, that is if the front of the hinge pin is higher than the rear, this is anti-squat.

If your hinge pin is angled frontward, the rear of the hinge pin is higher than the front, this is pro-squat.

The amount of anti or pro-squat you are running is measured in degrees. Starting at zero degrees, when your lower control arm or rear hinge pin is parallel with the ground.

Understanding anti squat and what it does can be a little confusing at first, but once you have it figured out it is an easy concept.

The basic idea behind anti squat is to artificially lower your center of gravity. With all mass of your rc vehicle setting on top of your chassis this causes the center of gravity to be above the tires.

With the center of gravity almost always being above the tires your rc vehicle is going to want to pitch, front to back, on acceleration and braking and roll, side to side, in the corners.

If the center of gravity was equal to the same height as the tires anti squat would not be needed, since there would be no pitch or roll.

Now let us look at how anti-squat artificially lowers your center of gravity.
To start off draw an imaginary line from your center of gravity to the ground. This line is called your level arm. The longer your level arm is the more pitch and roll you are going experience.

Now draw an imaginary line through your rear hinge pin towards the front of your rc vehicle.

Where this line intersects your level arm is the pivot point of your rc vehicle.

To see how your pivot point changes, first draw that imaginary line through your rear hinge pin at zero degrees of ant-squat, hinge pin being parallel with the ground.

Now add 2° of anti-squat. Draw another imaginary line through your hinge pin. This now causes the line from the hinge pin to intersect your level arm higher.

The causes your pivot point to rise, thus artificially lowering your center of gravity.

The function of anti-squat, like its name, is to reduce or increase the amount of weight transfer to the rear wheels under acceleration.
Also, it can help some with weight transfer to the front wheels under braking, but this can be controlled with changes to the angle of the front hinge pins.

The angle of the front hinge pins is referred to as anti-dive or kick-up. Anti-dive and kick-up help with weight transfer under braking and on and off-power cornering.

Anti-squat's major function to help with forward traction under acceleration and on and off-power rear traction.

As you increase the angle of anti-squat, this has an effect on the action of your rear suspension.

With your anti-squat set to zero degrees your rear suspension swings in an arc the is straight up and down.

When you increase the degree of anti-squat the plane that your rear suspension swings on also increases. Now instead of swinging straight up and down your rear suspension swings up and back. This causes your shocks to bind up and be less effective.

As you increase anti-squat angle the rearward movement of the rear suspension arm during compression places a bending force on your shock shaft. This makes your rear suspension feel stiffer or tighter.

Lowering anti-squat angle will make your rear suspension feel softer or looser.

The best way to compensate for this bending effect of the shock shaft as you increase anti-squat angle is to reduce shock oil viscosity or increasing hole size of your shock pistons.

Also, as you reduce anti-squat angles and thus reduce the bending effect on the shock shaft you would want to increase shock oil viscosity or reduce hole size of your shock pistons.

The Effect of Anti Squat Angle Changes


Increasing Anti-squat Angle
1. Increases rear traction during acceleration.
2. Reduces off-power traction.
3. Best used on smooth and/or slippery tracks.


Reducing Anti-Squat Angle
1. Reduces on-power traction.
2. Increases off-power traction.
3. Best used on rough and/or bumpy tracks.


A few other subtle effects of anti squat, especially with on-road cars are:
1. On corner entry the rear suspension will resist lifting.
2. If you use a stiffer front spring and have little rear droop may result in less off-power steering.
3. The maximum roll point of the rear suspension is reached faster.
4. Off-power steering mid-corner will be reduced until power is applied.
5. On corner exist the rear suspension resists squatting.
6. With reduced rear weight transfer on-power steering increases as throttle is applied.
7. Reduces rear grip on corner exit.
8. The rear suspension has a better ability to handle large or successive bumps.



Now let us look at the opposite of anti squat that being pro squat.
With the rear hinge pin angled frontward. This rc suspension tuning function is mainly used on an on-road car.

If you try running pro-squat on off-road vehicles can has disastrous results.

With off-road vehicles using long travel suspension arms a pro-squat setting will cause the rear suspension arms to travel in an arc that is up and forward, not good.

This will cause your rear suspension to lock-up sending your off-road vehicle bouncing all over the place.

But, pro-squat has a definite use and advantage when used on an on-road car. With on-road cars using shorter control arms and having less suspension arm travel, pro-squat is a tuning option.

How Pro-Squat can affect your on-road handling.

1. With transferring less weight rearward and more weight forward off-power steering improves.


2. Off-power steering increases mid-corner until throttle input is added.


3. With more weight being transferred rearward increases rear grip, but reduces on-power steering upon acceleration.


4. The rear suspension has little or no ability to handle large or successive bumps.


5. Best used on rubber tire setups.


6. Best used on low-bite smooth tracks.

If you are needing just a little more forward bite out of a corner try reducing the degree of anti-squat. Do you need just a little more on-power steering try adding a little more anti-squat.

Changing anti-squat angles is one of the quickest and easiest rc suspension changes you can make.

Plus, it can give you that little extra you are looking for.

Roll center is the point on your chassis, both front and rear, the point your rc vehicle pivots on in a corner. In most cases the roll center will be different on the front and rear, since we hardly ever have the front and rear suspensions setup the same.
In a corner centrifugal force causes your rc car or truck to lean into the corner. The point at which your front suspension pivots on is your front roll point and the same holds true for the rear suspension.

When you draw an imaginary line between these two pivot points is your chassis roll axis.

When determining your roll center you are going to need to remember some geometry.

Because , roll center is the angles of your suspension components, lower control arms (A-arms), and camber links or upper control arms (A-arms), center of gravity and center of your contact patch.

So, it is not easy calculating your roll center. Many full size race teams have a team of engineers working on this full time.

But, with a little practice and patience you can master determining and adjusting your roll center.


The first thing you will need to do when calculating your roll center, is to find your instant center.
Referring to the photo above.

Starting at point "A", the upper and lower control arms outer mounting points draw an imaginary line through point "B" in inner upper and lower control arms mounting point.

Then continue these two lines out till they intersect, point "C". Point "C" is your instant center.

When you change the angle of your upper control arms this will either move your instant center nearer to or farther away from the opposite tire.

The closer you have your instant center to the opposite tire the more negative camber gain you will have in a corner.

To move the instant center closer or farther from the opposite tire is accomplished by either lowering or raising the upper control arms inner mounting position or the outer mounting position.

The closer your instant center is to the opposite tire the more negative camber gain you are going to experience and the less static negative camber you will need to have dialed into your vehicle.

Understanding camber gain and taking full advantage of it can improve both straight line and cornering performance.

It allows you to always have the maximum contact patch on the racing surface. More contact patch translates into more traction.

How camber gain works, as you first enter a corner your suspension has not yet reacted so your negative camber setting initially holds your rc vehicle stable and maintains traction.

As your suspension starts to compress and the chassis starts to lean into the corner your negative camber setting will increase.

This helps to keep your outside tire flat on the surface, while the opposite happens on the inside tire. As your chassis rolls into a corner in inside suspension decompresses reducing negative camber allowing only the inner most of the tire to be in contact with the surface.

Understanding instant center and negative camber gain is very important to monster trucks and truggies, because of their higher center of gravity, longer control arms, large side walled tires and weight.

So, taking advantage of camber gain can result in the best of both worlds only a few degrees of static negative camber for great straight line traction.

While at the same time having a quick negative camber gain entering a corner, for great cornering speed and stability, with the maximum contact patch as possible.

Referring to the photo above.
Find the instant center of both your left and right side.

Draw an imaginary line from your instant center, point "C", to the center of the contact patch of that tire, point "D".

Where the lines intersect from the instant center to the center of the contact patch is the roll center for that portion of your suspension, point "E".

Repeat for the other end of your vehicle. The imaginary line through the front and rear roll centers is your roll axis.

Referring to the photo below.

The important part of understanding your roll center is your momentum arm.

This is the line from your center of gravity to your roll center. This line will increase or decrease as you change your ride height.

As you raise your ride so will your momentum arm increase. This will also increase your chassis roll in a corner.

While lowering your ride height will decrease your momentum arm and decrease chassis roll.

With all the variables in adjusting and tuning your suspension there are no hard and fast rules as to just how this is going to affect your rc vehicle.

It is some thing that you will just need to play with to both suit your driving style and conditions.

Just remember that roll center, instant center and momentum arm are all related and have subtle effects.

As you get closer to getting your rc vehicle "dialed-in" for conditions playing with or changing roll center and instant center could just add that little advantage you are looking for.

With there being some many different adjustments on almost all rc vehicles that are easier and have bigger results leave any tweaking to roll center and instant center to one of the last fine tuning points.

So, you have worked hard on all the different aspects of tuning your rc suspension and you think you have just the right setup.

But when you go to the track for testing your rc vehicle still does not perform or handle the way you want it to.

One thing that many of us forget to check is to see if our suspension is working freely.

That is to say is it binding up at some point? Or is it sticking at another point?

Taking an hour or two to check your rc suspension to see if it is working freely is time will spent.

It can and will result in you making suspension more reliable and produce more consistent handling.

Let us first start with checking all control arms.

Remove all wheels, shocks and sway bars.

Place your rc vehicle on a work stand so all control arms are hanging freely. Your control arms need to above your work table and not touching your work stand.

Now start on one corner lifting the control arm up to the top of its range of travel. Let it fall. If it falls freely to the bottom of its range of travel, that suspension arm is working freely.

But if it does not fall freely on its own or stops before reaching the bottom your suspension arm is binding.

Fixing a binding problem is just a matter of elimination.
It could be your hinge pin is binding in the control arm.

This is easy to fix. Using a hinge pin reamer or a drill bit. If you use a drill bit you need to be very careful.

For 1/10th scale on-road cars you will need a 3.0mm drill bit and for 1/8th scale off-road you need a 4.0mm drill bit.

But do double check your owners manual to see the size of hinge pin your are using. This will determine the size of drill bit.

To make this job even easier Hudy™ makes a 3.0mm and a 4.0mm arm reamer.

Plus, Kyosho™ has a 3.05mm and a 4.05mm straight reamer. These reamers makes this job much easier.

Using the correct size drill bit or reamer run it through the hinge pin hole in the control arm a few times. This will loosen the fit of the hinge pin in the arm and eliminate any binding. If you do use a drill bit, use a vise grip or pliers to turn the bit in the control arm.

Or a T-handle Tap Wrench works great. Using an power drill you could egg shape your hinge pin hole in the control arm, not a good thing to do, would cause too much play or slap.

Another area that you control arm can be binding, is where your control arm touches the suspension mount.
If the control arm is just a little larger than the area between the suspension mounts, this will cause binding.

Using an emery board or a piece of fine sand paper, sand down the outer edges of the hinge pin holes on the control arm. Take your time doing this, you only want to remove just a small amount of material at a time and check fit.

If it is still too tight remove a little more and recheck fit. By just removing a little at a time you find the point when the control arm fits just right in the suspension mounts.

Not too tight or too loose. You do no want to remove too much material off the control arm as this would cause the control arm to slide front to rear and vice versa in the suspension mount.

If your control arm was sliding back and forth in the suspension mounts this would cause ill handling characteristics. So, do take your time and be careful, you do not want to ruin a control arm.

Is your rc suspension still binding up, what could it be.
Do you run a pillow ball type of suspension?

Are the pillow ball clamps too tight?

If the pillow ball clamps are set too tight can cause your rc suspension to hang up and/or bind up.

Using an Allen wrench loosen the screws in the pillow ball clamps. Just loosen them a small amount.

If you go too far this will cause your rc suspension to be sloppy.

But, if you do go too far this is easy to fix, just tighten the screws a little.

If you are running a C-hub or steering block type of front suspension, you are going to need to check where the front hub carrier mounts to the control arm.
Does the hub carrier fit too tightly in the control arm. On many rc vehicles this is where the spacers are placed to change wheelbase settings.

You want the hub carrier to fit into the control arm tightly, but not too tight. If it is too tight this can cause binding.

It is not very common, but I have seen it.

If the hub carrier is binding, using an emery board or sand paper, just remove a small amount of material from the hub carriers mounting point.

Just remove a small amount a check fit. You are looking for that just right fit again. So just remove small amounts and check fit.

Do the same on the rear hub carriers and again be careful, because this is the wheelbase setting options on many rc vehicles.

The last thing you are going to need to check is all the ball joints.

This is a common area for binding on a rc suspension.

The bad thing is there is not much you can do to correct it.

An option you do have is to pop on and off the ball cup a few times till it starts to free up.

This is just a trail and error type of thing. Pop the ball off and then pop it back on and check it to see if it still binding. If so, try it again. There is no set rule to number of times it is going take to free it up.

One other option you have is to remove the ball joint from the suspension and place it in your power drill or Dermel and polish it. Using a rag and some metal polish. This again is a trail and error type of thing. Polish a little reinstall and test to see if it helped.

Most often I try polishing the ball joints as not to weaken the ball cup. But I know many other rc racers that just pop the ball cup off and on and have success freeing up the ball joints.

It does not matter if you run on-road or off-road all rc suspensions have become very precise pieces of equipment. All rc suspensions are engineered and designed to be performance enhanced.

So do take the time and check to see that your rc suspension is working freely. This will let your suspension work to its full potential. Plus, it could just give you that little extra to win that big race!

Anti-dive and kick up are much like anti-squat, while anti-squat deals with just the rear suspension.

They both refer to the angle your front hinge pins are setting at relative to the ground.

The major function of both is to control the amount of weight transfer on to the front suspension during braking, on-power and off-power. By controlling the amount of weight transfer this will have many advantages. Braking on corner entry, the amount of traction mid corner and forward traction on corner exit. Plus, it determines how your rc vehicle id going to handle bumps, ruts and all other rough stuff.

Total kick up or anti-dive = chassis kick up or anti-dive + front suspension mount kick up.

Plus, both anti-dive and kick up have an effect on your total caster angle.

Your total caster angle = caster angle + chassis kick up angle or anti-dive angle + front suspension mount kick up.

For an example if, chassis kick up = 7.0° and suspension mount kick up = -1.5°, total kick up = 5.5°. If your are running a caster angle = 15°, this makes your total caster angle = 20.5° with kick up.

Like anti-squat, both kick up and anti-dive artificially raises or lowers your center of gravity, which either lengthens or shortens your level arm, thus raising or lowering your pivot point.

This can have a huge effect on your cornering and braking, plus how your rc vehicle is going to handle bumps.

Now that I have you totally confused, let us look at each of these separately.
When you look at your front suspension from the side, with the wheels off.

If the hinge pins are tilted forward, the rear of the hinge pin is higher than the front this is anti-dive.

But, if your hinge pins are tilted backwards, the front of the hinge pin is higher than the rear this is kick-up.

As a general rule I never see a reason to use anti-dive on off-road rc vehicles. Since you would loose your ability to handle bumps, ruts or any other rough stuff.

On the other hand anti-dive has many advantages when used on on-road rc cars.

While kick-up has its advantages on both off-road and on-road rc vehicles.

The effects of anti-dive on on-road cars:

1. At corner entry the front suspension resists compressing.

2. Off-power steering is reduced by less forward weight transfer on corner entry.

3. Front end grip is reduced on corner entry by less forward weight transfer.

4. On-power steering response is reduced by the overall reduction in caster. Can compensate by increasing caster angle.

5. Front end grip is reduced until throttle is applied, corner entry and mid-corner.

6. On-power and at corner exit the front suspension will increase compression.

7. Increases the amount of time, in a corner, the front suspension takes to reach its maximum roll point.

8. Reduces your rc car's ability to handle any kind dumps, ruts or rough stuff. Running softer front springs helps to eliminate this problem, but not entirely.

9. This setup works well on medium to high grip tracks in combination with a weight forward bias.

How kick-up effects both on-road and off-road rc vehicles:

1. With transferring more weight forward, off-power steering improves.

2. Front end traction is increased with more forward weight transfer.

3. With total caster being increased on-power steering and front end traction is improved.

4. Front end traction and steering is improved through mid-corner.

5. Your front suspension can better handle bumps, ruts and rough stuff.

How changing kick up angle is going to affect your handling.

The effects of less kick-up:

1. Off-throttle forward weight transfer increases.

2. Increased forward weight transfer under braking.

3. Under braking and off-throttle front suspension compresses more.

4. Reduced steering response.

5. Better when used on bumpy, rough tracks.

The effects of more kick-up:

1. Off-throttle forward weight transfer is decreased.

2. Reduced forward weight transfer under braking.

3. Under braking and off-throttle front suspension compresses less.

4. Increased steering response.

5. Better when used on smooth fast tracks.

Always remember than any changes to kick-up and/or anti dive is also going to change caster.
Another thing to keep in mind when you make any changes to kick-up and/or anti dive is to make the same change to both sides of your front suspension.

Also, if your rc vehicle has upper control arms on the front suspension, make the same changes to them.

The upper and lower control arms need to be parallel.

If you do not keep them parallel your front suspension will bind up or worse yet it could lock up. Either would produce terrible results.

http://www.rc-truckncar-tuning.com/rc-suspension-tuning.html

It Sometimes helps to check out the pics to make understanding the tips easier.