I've taken my car to some all day auto-x schools recently and have noticed some unusual wear on my rear passenger tire (only). Towards the outside of the tire there is a thin strip of rubber that has been peeled/ripped away that appears to have been rubbing the inside of the fender. The problem doesn't exist on the driver's side.
I'm on Konis/Eibachs, with the Konis at 75% in the rear. When at the track, I remove junk from my trunk.
I'll post some pics later, but I'm pretty sure it's the fender eating the tire. Has anyone experienced this before? I assumed this was only a problem for people slammed on coilovers or with oversized tires. Mine are 235/45/17, well within spec.
If this is as unusual as I suspect it is, what could cause it? Could there be a problem with the install of the suspension? Could inflating my rear tires to 40 psi be a problem? I'm stumped here....and in the process of finding someone who can roll my fenders before the next auto-x.
Ideas?

 

definitely roll your fenders. i only rub on the passenger side rear as well when fully loaded AND with rolled fenders. but then again im running a more aggressive setup. perhaps it has something to do with the rear beam when the car is lowered and loaded.

 

Recenter your beam. What offset wheels are you running in the rear?

 

Easier said than done man.....I just don't see why this happens to me and not to other people with similarly mild setups. And why only on the passenger side?

I did a quick search and found that the 17x8 wheel came with a 35/45 offset. Not sure which I have though, as I bought them used from another member.

 

you asked what the problem was, they told you the beam is off center. recentering the beam, narrower tires, or rolling the fenders are the solutions. If you don't like them, that's not our problem.

and just because other people don't have that problem doesn't mean you shouldn't either. your driving conditions and style are different than the others, so your problems will be different as well.

 

i had the 18x8 +45 RPM2 with 235/40 tires and i didnt have to roll my fenders, even under extreme cornering. obviously when i added a 25mm spacer, the fender starting eating up my side walls like crazy. hence the roll.

do roll your fenders first and see if that takes care of it, which i think it would. given that you are not as low as I am, you should be fine with just a roll. easier than recentering a beam yah?

 

Hey, I'm just trying to figure out why it only happens on one side and if there are other possible reasons why this is happening. No need to have an attitude about it, I'm just trying to learn.

Mr****s95SE: Did you have the problem on both sides or only on the passenger side? I'm looking around for a reputable guy to roll my fenders. Yes, it sure is easier than recentering the beam

 

well without the roll, i had problems on both sides, thats with my GC setup so the drop was pretty low. but after i rolled, the passenger side, when the car was fully loaded started to rub rather than the driver side. so im guessing its the beam that needs to be recentered. if you roll and it still rubs a little bit, try pulling the fender a bit. that should take care of it without recentering the beam.

i believe you can rent a fender roller from you local autoparts store (ie: kragen, pep boys, etc.) a good wheel/auto shop should have a roller. or you could do the ghetto baseball bat method, which i half did (then decided to use a roller in the end). doesnt come out as clean as a roller obviously but gets the job done. :P

 

It only happens on one side because your beam is off-center. As in, when you lower the car the bushings bind and the entire rear unsprung mass shifts over to one side. Recenter your beam and your car will at least be symmetrical.

It is not that hard assuming you have floor jack, jackstands, torque wrench and a breaker bar (and a ruler or tape measure).

 

too much work already. its so minor on mine. im not worried about it. plus the fact im super lazy right now.

 

if you took a second to think about it should be obvious. the beam is off-center meaning it is to one side or the other which pushes your tire into the fender.

simplest solution: roll your fender. this will fold the innner metal flat and give you ~1" more room.

i'm not exactly sure if there are any negative effects of having the beam off-center so i'm not sure if recentering it is justified.

this is not advanced suspension.

 

That might have been relevant if I were talking to you

Positive effects of recentering beam: more predictable handling left-to-right, a car that's symmetrical. It's sort of parallel with getting your car corner-weighted.

 

ouch pwnage.

well i dont see corner weighing/balancing my car a high priority. look at it. would you? a track car on the other hand a definite yes. so 95maxrider, i would, but if its so small, i probably wouldnt worry too much about it.

 

I haven't tried to model just what the Scott-Russell linkage might do under various conditions of bump + roll, or attempt to find the point(s) about which the rear of the car actually does roll (hint: it isn't necessarily about the kinematic roll center). But I do suspect that it is not truly symmetrical, as the bushing compliances matter. If you look at the S-R, it's closer to a panhard bar than it is to a Watts link.

Then too, sheetmetal has its tolerances. Perfect in terms of chassis measurement & alignment may well not be in terms of fenderwell clearances, and a "miss" on the driver side of only 1/64" might as well be by a mile. Do you know how close to rubbing your car is on the DS rear?

I understand that recentering a S-R is more involved than swapping in an adjustable PHB on something like a 3rd/4th gen F-body or a S197 Mustang. But offering up what sounds like resistance to doing the fix comes off as just more complaining. Your specific car may be dimensionally different by just enough here and there to have this as a problem where some (or perhaps most) others don't.

I have no idea about the two offset numbers for this car, though I have seen different offset wheels used on other cars, for front vs rear (F-body world, for the curious). I suppose that if the RR needs a +45 offset wheel to clear and that for any reason at all you've put a +35 wheel there instead that you might have a mild problem.


Norm