Jack667

I wish I had photos of the tire - actually - maybe I'll get them tomorrow from the shop, but suffice it to say that the inside sidewall of my rear driver tire is chewed up, to the point of showing cord in one or two big spots. Almost the entire circumference is chewed up to some extent. It is really pretty scary.
A bit of background - my car has a wide-body kit on it and extra large wheels and tires to fill the fenders. The wheels are 18" and 8.5" wide in front and 11" wide in the rear. When I had the custom measurements done and custom wheels made, I had a test pipe on with no cat. Four years ago, I needed the cat to pass emissions in GA, so I went looking for my old cat. Couldn't find it so I bought one from someone on Rennlist. Not sure if it was the exact one for my car...
I have 315/30 tires in the rear now, and I don't remember what I used to have. I have changed the config a bit in the 6 or so years since I've had the wide fenders.
So, the cat seems to be the culprit, per inspection of protruding items, and based on the shine on the offending piece.
This seems to be a bracket that is not needed and I assume I should get it shaved off.
The new tires that I'd ordered are 295/30, but they seem every bit as wide, so no help there. I could maybe add 7mm more of spacer, but that's not enough - those cuts were deep! So I guess my only option is to shave the bracket.
Here are the photos (see below)
I am interested in any comments about the plan to shave that down, and any alternative suggestions.
I eventually found my cat converter and its in the attic, but I don't think I want to bother retrieving it, inspecting it, and possibly swapping them.
This is on a 1990 C4.
Jack

Marc Shaw

Assuming you are referring to the square brackets that stick out, they are for heat shields that you obviously don't have. It should be easy to cut them off with an angle grinder.

Marc
p.s. If it were the cat brackets, however, I would have thought we'd see a few rubber chunks hanging off the offending bit of metal.....

Duck

With the standard cat, is it a lot of heat back there with no cat heat shields or the plastic heat shield to protect the valve covers. I had considered running like this, however it seemed that everyone said that you needed the heat shields in place.

Jack667

Mark - sounds about right - there is no heat shield on this car. The 'evidence' is the shiny portion of the bracket. It's the only shiny thing back there. Also, not that the shiny-ness is directional for the tire...
Duck - I've been running without a heat shield for 8+ years with no issues. This is one of those topics that keeps coming back. I always thought the conclusion was to take it off.
I'll see about posting the pics of the tire later today.
Thanks for the comments!

Jack667

Here are the photos of the tire.
More interesting to me is that I cut off the shiny piece of heat-shield bracket from the cat, mounted the new tire, and notice that it is pretty far rear of the car and I wonder if it really could be the offending item.

Please examine the wheel well photos above (I guess they're not that good, as they don't show much of the wheel well) and let me know if you have any other ideas on what could have caused this damage to my inside tirewell.

Thanks!

garrett376

take photos all around your wheel arch and post them on here...

RSGulp

I think you've picked up a piece of debris off the road which has jammed somewhere (maybe near the cat) and has shredded the tyre wall. It would only take a few seconds at speed to do this sort of damage to your tyre before the debris found it's way out of the wheel arch.

In your first photo there is a bent up bracket to the left of the exhaust flange. Where is this relative to the tyre damage? Could it be the cause? - or it could have got bent when a piece of debris jammed in there. Is there any damage inside other areas of the wheel arch which would suggest debris getting stuck?

Jack667

Thanks for the new comments - I thought I should change the thread title to get more folks to looks at the tire pics, but I can't figure out how to do that - so I am glad that you guys took a look.

I'll take the new tire off and take some photos, but there is nothing odd about that rest of the wheel well.
Then again, maybe I'm missing something.

That bent up bracket is interesting. I'll also take another look at that. While I was under the car yesterday, hacking off the bracket, I pounded that other mess flat. I think it is more toward the tire damage, but further recessed, away from the wheel - but atleast it's not as far back as that other bracket that I modified. I wonder what that bent up bracket was for? Maybe there was more to it. It looks like it was broken.

Considering that the cat has been on for 4 years, and that the heat shield has been off for 8 years, I really do fine it odd that the heat shield bracket was shiny, though...

RSGulp

I just went out to the garage to look at my car. The brackets on the cat (the one you ground off) are about 5" behind the outer circumference of the tyre. I think that's too far back to cause the damage to your tyre. The top bracket and sensor were probably polished clean by grit/spray being flicked up by the tyre which is why they're shiny. Notice how the red paint above them is also cleaner in that area.

The 'bent up' bracket in your picture should have held the front of the heat shield. I think this is the cause of your damage. It looks like it has shredded your tyre and got mangled/broken in the process. I guess something must have bent it towards your tyre originally - like a high kerb or maybe something like a rock flicked up from the road.

Grind the sucker off or hammer it flat and you should be okay from now on.

Jack667

Thanks Rich - that's very nice of you to go out to your car and check that out! Much appreciated!
Jack