More tech info

Front Suspension Set-up for Cornering

On all circle track cars, stock cars to modifieds, when a wheel is cambered, the tire generates a lateral force known as "Camber Thrust." This camber thrust can work with you or against you in the corners depending on your front end alignment and suspension geometry.

For the camber thrust to be working with you in the corners, the top of the tire should be tipped in the direction that you want to turn. This is the basic reason that a circle track race car has positive camber on the left front wheel and negative camber on the right front wheel. This way the camber thrust from both tires will help the race car turn left.

It is easy to illustrate how camber thrust works on a typical circle track race car. Start in a good size shop (not a little single car garage) and remove the rear stagger. Nexr, aim the front wheel straight forward and then lock the steering wheel so that it can not move. Now, by hand, push the race car forward from one end of the shop to the other. You will notice that as the car moves forward it also drifts off to the left, even though the wheels are pointed forward!

However, if the top of the wheels lean toward the outside of the corner, then the camber thrust would be in the opposite direction and reduce the cornering force at the front of the race car.

CAMBER CHANGE
At speed, in a corner, the race car's body rolls (leans) to the outside of the corner. With the old VW suspension used on many dune buggies, if the body (or chassis) leans to the outside 2 degrees in a corner, then the front wheels will tilt that same 2 degrees to the outside. In this example, the wheels would be cambered in the wrong direction to have the camber thrust help generate a larger cornering force. When this is the case, the front tires will lose traction sooner than if the tires were cambered in the correct direction.

With some A-frame suspensions on older cars (60s & 70s), when the body leaned to the outside in a corner, the wheels would lean to the outside to a larger degree than the body actually leaned. On most newer production cars, when the body leans to the out side in a turn, the wheels typically lean half as much as the body, but it is still in the wrong direction to take advantage of the camber thrust. Most racers use more static camber to compensate for the loss of camber in the turns, but this additional static camber nibbles away at your straight line directional stability.

This is why evaluating your suspension geometry and making the necessary changes can be rewarding in how your race car handles. Programs like the Front Suspension Geometry Pro software can be a valuable tool in maximizing your cornering force and improving your handling.

Using these programs, you can quickly and conveniently try different mounting positions or A-arm lengths on the computer and immediately see how the camber changes when the wheels move up or down (as in body roll).

Remember, racing can be dangerous. Always use your best judgment and the best tools!

More tech info

Auto-ware main page

Copyright AutoWare 1998