One important factor of rc suspension tuning is knowing how anti-squat and pro-squat is going affect your handling.

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.

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.

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.

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.

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.

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