which is the best way to measure crossbind given that you have a 4 corner computer scale

1) do you want to measure it without the body on

2) with the body on

or

3) with the body on and the kid in the car?


THANKS

Option three is definitely the most accurate for actual racing conditions.

If you do it with the shell off you should double check it with the shell on because you can induce crossbind if you are not careful while installing the shell.

Dick Thornton

I would say you will induce at least some cross-bind when attaching the shell. I really can't see it not affecting the cross-bind a little.

I have a question. I use a bed frame & a small bottle jack (to lower slowly) to check my cross bind I check w/ the body on & no driver. Do most of you check with the wheels on or check the spindels. I check w/ my wheels on ?.

I added dead weight the last time i set the car up the kid wiggles too much
I have a jig that i set the spindles on, I made that I put string across the point from corner to corner to make sure its flat then I use feeler gauges to check for bind I wish I had the money for a digital scale but my rack cost me $100 to make compared to a $1000 for scales

Is it more accurate to set the crossbind by a 4 scale pad than to use rails? If you use rails, shouldn't you be checking the square stock and not the spindles?

I use rails and set the car on the ends of the square stock. I prefer to eliminate as many variables as possible, and using 4 scales keeps to many in play. When using 4 scales, your alignment better be perfect, all of your wheels better be the exact same diameter and all of your scale surfaces better be on the exact same plane and have the same travel hysterisis. In my mind 4 scales will not accurately check cross bind but it will check weight bias. Those of you using 4 scales run this a little experiment. Get your method all set up. Get the car where you think you have "0" cross bind. Now place a 5 pound weight on an axle near the wheel. Did your reading change? Did you just add cross bind to your car? Of course not. So is your method as accruate as you would prefer? Maybe not.

Here is another experiment for those of you that check cross bind on your wheels. Get all set up to be perfect. Now swap two corner wheels. Still perfect? Or place a popcycle stick under one wheel simulating a taller diameter wheels. You will now think you have cross bind based on your previous base line. But do you?

JJP

We check cross bind with a jig that can be adjustable to make sure it's perfectly level at all 4 corners. We use an electronic level to check all points to make sure it's zero. Like I said it's adjustable and can be leveled. We used 1' Diameter bolts with the Heads machined flat on to set the spindles on. The bolts are fully threaded and are the adjustment devise. They are bolted to a steel bar (2) one for the front and rear. The front bar can be moved to adjust to different wheel bases. These bars are bolted to a work table with holes pre-drilled for the different wheel bases. Once locked in you level the settings and there you go.

We decided to go with the spindles as the location area as there is a chance the spindles are not cut directly in the center of the square stock. May be off just a hair. Probably over kill from that perspective.

The key I think is no matter what system you use it must be square to the world when you start. Lots of ways to achieve the same goal as long as the starting point is correct.

Have a great day.

Roger Van Waart

What Roger just told you is that he uses Rails. It is a modified execution but still rails. I have used his table and it works well.