race911

Pulled these RA1s off the rear of the yellow car (picture 1). (If you followed the videos from 2 weeks ago, you'll understand what I mean by nursing crap rear tires for a day.) Typical ~500 miles of use.

Comparison to the last set I pulled off (picture 2) of similar mileage, just changed out since those were also crap + the fronts I had on finally corded. Each of the other sets of RA1s I've used since I bought the car (or running on the RSA, which was significantly softer) wore as these did. Cord in the middle, if anywhere.

Typical RS alignment, only thing I changed was a bit of weight jack and since I finally had the Walrod tool, equalized the K-Toe.

Similar to anyone else's issues?

Warpig

I have never taken a set of rears off my 95 and had them not look like your picture #1 I get about 6K-8K miles on a pair of rears and can smell burning rubber when I park the car after a 30+ minute drive. I can also draw pictures in the rubber dust collected on the paint on the side of the car behind the rear tires.


So far it seems I will go through 4 sets of rears in the time I go through 1 set of fronts. mind you I dont track the car at all. All street driven so far.

Nick

Mike J

That does not sound right...it should be more like 2 rears per 1 set of fronts. What are your alignment specs?

race911

Ditto. No way, no how should you have corded shoulders on a street driven car. I can't even remember the last time I wiped rubber off the body, maybe at a cement airport autocross 20+ years ago?

trophy

To me it looks like a toe in issue, I have seen it before with cars that have too much toe. But if you alignment is within spec, I am a little confused.

Would be good to see the specs of your last alignment though.

Do you have an adjustable toe link like an ERP or Tarret on your car? If not the stock ones have been known to move out of alignment.

race911

1/16" in on each side. Don't remember the K-Toe, but it was equalized and wherever on the bubble it's supposed to be. There's no thrust angle to confuse things, either; I figured out how to measure from a centerline when aligning 911 #1 circa 1981.

Car has no rubber in the suspension.

Consulting with our resident local race fab/setup guru, he's also got no answers.

Further data point is that the tires really weren't overheated in that I'm pretty religious in keeping them in the 38-40psi window. I did not deal with a pyrometer ever on this set, though. Nothing's been amiss for four years, and the alignment specs are pretty well known, so I didn't bother.

Jim Morton

Ken:

It's been a while since I've touched a 993, but as I recall from all the alignment work I did on my cars, when you adjust an inbalance on the K-Toe, you get significant change in rear camber when the K-Toe arm is adjusted. From memory, I had to go around the adjustment(s) twice, once I set the K-Toe, then re-checked it after doing the other arms.

Were all angles of the rear settings checked when you moved the K-Toe ?

$0.02

race911

Yep. Wouldn't have called it a day unless everything was rechecked. It was my first time using the tool, so it was partly educational.

(This whole multi-link thing really has me nostalgic for a 964. Or even a torsion bar car. EZ alignments, and there really isn't any difference at the limit.)

993RS

I get 3 rears per 1 set of fronts. Get 3K miles on the rears max. Lots of hilly and winding road driving.

trophy

Ken, I would string the car up again and see where it is sitting, realistically the only thing that can be going wrong here is a toe issue. Do you have a rod end on your toe or K-toe links that has gone bad, causing changes under load of this alignment. Have you broken a rear swaybar link causing the backend to be loose (as per the video). What about wheel bearings, is there any noise or movement?

Just throwing ideas at you here

Warpig: You need to get your car to an alignment ASAP, you are burning rubber that doesn't need to be burnt. I get about 1.5 to one fronts to rear on my 80% track car, and never ever rub tire rubber off the rear of the car.

Jeff96-993

I have a set of track tires that look just like that, corded on the inside. Haven't had track time yet to test my new RS bushings and Tarret links, but I'm thinking I'll get the same condition. Will look up the alignment settings tonight, but my direction to the shop was "aggressive" but not full-track.

And ROW M030 including bars, with heights as low as the alignment guy could get it during corner-balance.

race911

You shouldn't. The last four sets of rear RA1s I've had on the car wore down similar to pic 2.

I spent the day on a totally different refurb project (see pic), so my report back on if anything went wildly amiss will have to wait for next week.

Warpig

Hmm... Even my first set of tires right after getting the car back from alignment and corner balance displayed this tire wear, burning rubber smell, and rubber dust. I also went to a place that everyone swears by that is supposed to be VERY good. hmm here is all the info i can throw out that i have that may help someone help me identify the issue. Car went in to have Bilstein HD's installed, aligned, corner balanced and have ride height raised slightly as I was getting bump steer in the back at times the car was so low. The car was low enough and I didnt like the feeling of the bump steer and wanted it corrected.

HD's installed, brought to my attention I needed two new control arms (993.331.043.01) so I had those replaced, new tires all around from the tire shop the day before I took it in for this work. Car raised slightly, aligned, corner balanced. See printouts for all the specs.




I questioned the few alignment specs that were still out of spec (in the red) and was told this was not uncommon. Are the red #'s the cause of my tire wear? It seems that the consensus above is toe had to be the culprit. but toe looks ok according to the results... No? I did mention this was a street car and not a track car. I asked them to align accordingly. Anyone who knows what this stuff all means want to chime in.

I am currently nearing the end of the second set of rear tires since this alignment. Looking at my receipts it's not quite as bad as it seemed but still bad. I got ~11,500 on the first set and am currently sitting at ~10,000 on this set. I will need my third set of rears in the next month or so. The fronts are the same as the day I took it in for this work and still have at ~50 tread left on them.

Nick

ppressle

Ken,
Spinning the inside tire perhaps? How is the limited slip?
Pete

Matt Lane

No matter how hilly and winding, there's no way you should be getting 3K out of a set of rear street tires. 2-3 times as much at least with an appropriate alingment.

Just trying to save you a few bucks on tires...

Best,

Matt