Rear tire rubs on bumps

[Naboo]

I have 315/35/17 tires on the rear and when I go over bumps, the driver's rear tire rubs. If I install a thin wheel spacer (1/8"), will that be OK? Are there any other suggestions?

[FUNFER2]

Don't you have adjustable coil overs ?

[Got the Bug]

Originally Posted by Naboo

I have 315/35/17 tires on the rear and when I go over bumps, the driver's rear tire rubs. If I install a thin wheel spacer (1/8"), will that be OK? Are there any other suggestions?

Installing a wheel spacer would probably make the rubbing problem worse. Raising the ride height is your best bet.

[Calbullet]

where does it rub ? inside or outside of tire. going from your statement, 1/8 " spacer, it rubs on the inside ??

[Tim Brewer]

If your tire is rubbing the outside lip of your fender, chances are you have the WRONG offset wheel. Look behind your rear wheels without jacking up the car, if there is room for the wheels to go in towards the chassis, there's the problem. You'll have to buy new rear wheels to ride and look correct, or raise the rear of your car and take the chance of looking a little odd.

[Thieleng]

I ran Hoosier 315x35x17's on my Superformance, before I put them on I had to modify the fiberglass interior to the body near the front section of the wheel well. You can go to my photo's and check out what was done. The amount of fiberglass removed varied between the right and left side. This was a fairly easy fix if this is where you are getting the rubbing. I also had the wheels widened to 10.5" by Stockton Wheel, this is the proper way to fit the larger wheels. I had plenty of clearance on the fender and the fix was more internal. I am only guessing this is where the issue is and I would recommend these two changes if you are using that size tire.

[Silverback51]

Avoid the use of a spacer if you can.

[Naboo]

It rubs on the inside of the fender. At about 10 clock looking at the wheel. I can try raising the suspension and see how that works. Sounds like the spacer is not the preferred choice.

[Naboo]

It looks like there is and adjustment on the suspension to push the top of the wheel out (turnbuckle?). Can I adjust that since it's rubbing on the top?

[mln385]

That will throw your camber off and handling,adjust your coil overs and ride height by about a 1/2 inch and see what that does.

[Calbullet]

if you adjust your coil overs, make sure you do both sides. you want your height even on both sides.

[scootter]

I have 335's on my car with 11.5" wheel with no rubbing issues. It sounds like the wheel spacing isn't right.

Scott

[Clois Harlan]

If you're rubbing on the inside go ahead and use the 1/4" spacers. They are cheap and safe. I have used spacers for years 1/4" and then 1" when I had to put on my street tires.

Clois

[FUNFER2]

Can you take a photo of the area ?
If so, put some light on it to get a good pic.

[trularin]

Set your ride height and get yer tires in.

[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.

[spf2551]

Blas
What should the height be at the front wheel flare?
Lyle 2551

[Blas]

I believe it's the same all around...26.5" - 27"..
I don't believe is a required height, just a recommended setting...
I know mine is a bit lower...
Also, if you have a coilover spring that is out of spec, that could contribute to the bottoming out on one side...you could try switching the rear shocks left to right...

[Naboo]

I measured the ride height. I'm at 25". Sounds like I need to start there. I'll go to 26" and see if it goes away (since Blas is 'a bit lower'). I'll let you know if it work (if it ever warms up here).

Thanks for all your input!!