HOW DO YOU GET RID OF CROSS BIND
Proper Cross Bind adjustment starts with your car's construction. During construction make sure your axles are installed as level as they can be to one another and to the floorboard. See more Cross-Bind construction tips in "Winning Ingredients for Kit Cars."
In this article we will continue with the Cross Bind final Adjustment. To perform the final adjustment the car must be completely assembled and your weight placed for racing. The forward and aft king pin bolts should be torqued to around 200 IN. LB.
The following Cross-Bind adjustment with Bed Rails is by Jerry Pierson. I use it with his permission. Jerry's Soap Box Derby accomplishments are legendary.
There are several methods to measure and adjust your Cross Bind; these are: Sighting across the axles from the front or the rear, Using a level positioned on the end of the axle and move it from axle to axle, Using 4 separate scales under each wheel, Using a flat concrete surface with your wheels on, or Building a parallel rail fixture.
In this article we will use a parallel fixture to check and adjust your car's Cross Bind. This method is a favorites of my friend Jerry Pearson. It is simple, fast, and accurate.
Use old bed frame rails to construct your Parallel Rail Fixture. The fixture side rails must be long enough to accommodate the wheelbase and the fixture must be wide enough to accept the max length of the axle square stock. The goal is to be able to set this parallelogram fixture up and lay a level across each end and make adjustments to each corner until the side rails are level, side to side, end to end and diagonally.
When your fixture is 100% level, sit your car on the fixture with the square stock of the axles sitting on the side rails at the same position on all four corners. Set the axle square stock ends on the rail, do not use the spindles. Now raise the front (or aft) end of the car just slightly off the rails and then back down until the axle makes contact with the rails. If both sides hit the rails at the same time, then you do not have cross bind. If one side hits the rail before the other, then you have cross bind. To remove this cross bind, loosen your front kingpin, (or your aft king pin) and put a . 004 feeler gage in between the two largest washers of your washer stack up against the side of the kingpin bolt. Now again torque your kingpin and recheck the car for cross bind. Continue this process with different thickness of feeler gages until both sides of your axle hit the side rails of your fixture at the same time.
Thanks Jerry Pierson for the above Cross Bind adjustment procedure with bed rails. Jerry's daughter Hillary won the 2004 Masters. See photo to the left.
A few things to consider when adjusting your Cross Bind are:
- Car should be complete with weight placed for racing.
- If using scales, make sure all wheels weight the same.
- Make sure your two or four scales are calibrated the same.
- Position the wheels all the way in using washers, or all positioned out, whichever you prefer.
- Axles should be torqued to 175 to 200 IN-LBS. to measure your Cross Bind.
- Place the shim between first and second washer above floorboard as shown in top left image.
- Check your Cross-Bind often.
Because of the large area of the washers above and below the axles, 200 IN LBS torque might be too stiff for some tracks and starting ramps. Because of this, often people race with 100 IN-LBS. for the front axle to reduce cross-bind on the starting ramp and rough tracks. Only testing can give you the correct torque.
See "Winning Ingredients for Kit Cars" to find out what others are doing to adjust their Cross-Bind. There is also information for adjusting your Cross-Bind with scales, and information on which axle is best to shim.