So how much cross weight do you tolerate.

[reddevilsix]

The set-up conditions I used are just a little different than what you may have seen before.


Seeing as how our cars have a solid (1 piece) rear axle, we are not completely able to set up our car as easily as you would be able to do if you had complete 4 wheel independent suspension.

Also I believe that the rear axle has more control over the setup of the car than does the front. After setting up two different cars and racing for 9 seasons, I arrived at what I think is the best way to setup the suspension.

1. Place a scale under all four wheels. Get the car on some level surface, if you can' find a level surface big enough in your garage, then use some sort of leveling device such as a piece of wood or two to get the car level front to back and side to side. This would be accomplished by checking the front and rear axle height from the floor and allowing for the difference between wheel diameter. The leveling devices should be under the scales Some run larger diameter rears than on the front. Alternatively you could just use a long level or a long piece of wood that is straight and a short level.

2. Put weight in the car to approximate the weight of the driver. Don't neglect the weight of the drivers legs and feet. Put some weight in the front as well as in the seat. I usually did the setup without body work on. Set the tire pressure to what it would be with hot tires. As the fuel cell is under the seat and in the center of the car, I never bothered to make sure it was full or not. However I always made a note of how much fuel was in the tank. If you have rocker friction on your car, loosen the friction devices. (make a note of how many turns you backed off on the friction device so you can set it back)

3. Now remove the front wheels. Put a block of wood no wider than 1" under the very center of the font of the car that will give you the ride height you want in the front. I always used a ride height of about 1.25" measured at the lower A-arm pickup point. This will be approximate as this will change as you adjust the rear suspension.

4. Now your car is suspended by the rear wheels setting on the scales and the block of wood in the front. Here is where you set the rear ride height and level the frame. Adjust your rear suspension to get the rear ride height where you want it, (I usually set it about 1 inch higher then the front.), and get the ride height the same of both sides of the frame. Pick a spot on both sides at the rear of the car someplace close to the rear axle.

5. After adjusting the ride height at the rear and getting the frame level, make a note of the rear wheel weights. What you get is what you have. There is no changing it, other than moving parts around. On my KBS, the left side was always a little heaver than the right as the left side had the battery and fire extinguisher.

6. Now put the front wheels back on and remove the block of wood from under the front of the car. Set the front of car on the scales and roll the car forward and back a little and bounce it a couple of times to settle the suspension. Make a note of all four scale readings. Make a note of your readings that this the first setup reading. Keep a log of the scale readings as you make adjustments. Unless you are extremely lucky, your scale readings will be less than perfect. By perfect I mean less than 5lbs cross weight.

7. Now set your front ride height. Make sure you always use the same location for measuring the height. I made a block of wood at just the height I wanted and used that as a gauge. A lot easier than trying to measure under the car. After setting the front ride height, check your weights again. (note, do not adjust the rear suspension during this process) Now adjust the front suspension to get your cross weight balanced. As you do this, you may have to check your front ride height again. At some point you will achieve the cross balance and ride height you were looking for. Remember after each suspension adjustment, to roll the car and bounce it to get the suspension to settle.


Other thoughts

You will need to recheck your cross weights any time you make a toe in, caster, or camber adjustment.

Most tracks run clockwise. Hartland Park is the only one I know that runs counterclockwise. Some people say that to make your car turn in better is to put a little more weight on the left front wheel as a majority of your turns will be to the right on clockwise tracks.

Your mileage may vary.