Rear tire rubs on bumps

[Blas]

I know there are 3 sets of holes in the upper shock mount bracket. I don’t have my car close, but I think the center holes are the stock position for the bolts thru these upper shock brackets. Perhaps someone can quickly check their bolt positions. Perhaps you should compare how yours are setup first. I’m not sure what the reason is for 3 different positions available for these bolts or what needs to be adjusted to switch the bolt hole positions. Have you replaced the factory rear shock tower brackets with the upgraded versions? If not, could one of yours original top brackets be sagging or bent?
I’d be curious to know if the distance from the face of the rotor to the chassis tubes is equal. You say only one side rubs, the drivers side, interestingly enough, that’s the side where the extra weight from the battery and the driver is too. Should you ever have occasion to have both the rear wheels off, maybe check the backspacing in the 2 rear rims. Is this a newer chassis or an older chassis? What is your car height set at? I believe 26.5” to 27” to the top of the wheel flare is recommended. Someone else had this problem last year if I recall, I don’t remember if it was resolved.

[FUNFER2]

When I was setting up my suspension, I made two 8" length of round aluminum that was threaded inside, and bought four heim joints to make shock replacement. I removed the coil overs and mounted these in place. I was able to adjust the ride height where I wanted and since we race sprint cars, we know a lot of modified racers so, I borrowed a set of four weight scales.

Before I started, each corner was so different in weight, I could not believe it. After adjusting, the weight is almost the same on each corner and the percentage front to back now is 51% in back and 49% in front.

Here's a photo of the tool I made. If your interested in making a couple (it's cheap) let me know or I could mail them to you, just for postage costs.

It's the best tool I've ever had to adjust weight, measuring for wheel & tire size and setting ride height.

[maxum_101]

Originally Posted by FUNFER2

When I was setting up my suspension, I made two 8" length of round aluminum that was threaded inside, and bought four heim joints to make shock replacement. I removed the coil overs and mounted these in place. I was able to adjust the ride height where I wanted and since we race sprint cars, we know a lot of modified racers so, I borrowed a set of four weight scales.

Before I started, each corner was so different in weight, I could not believe it. After adjusting, the weight is almost the same on each corner and the percentage front to back now is 51% in back and 49% in front.

Here's a photo of the tool I made. If your interested in making a couple (it's cheap) let me know or I could mail them to you, just for postage costs.

It's the best tool I've ever had to adjust weight, measuring for wheel & tire size and setting ride height.

how do you adjust the weight at each tire? is it done by the ride height?

[JCoop]

Yes. Usually best done after a proper wheel alignment.

Adjustments should be made with the sway bars disconnected, and with driver weight and half tank of gas. After adjustments, reconnect swaybars so there is no pre load on them. Not easy. took me 4 hours and 2 cases of beer and 2 friends.