rnridout

I am suffering severe wear on the inside corners of both rear tires. Actually had a blowout a year ago, and now have new wheels and tires, and it's eating the inside corners off of the rears. Thoughts?

jumper5836

stock setup has a lot of negative camber. This is so the car feels like it's on rails in the corners but will wear the inside shoulders on tires while not cornering.

You could probably get an alignment done and which could reduce ithe negative camber some to get a little more even tire wear but it won't be able to make it wear even.

jpflip

Agree with jumper 5836...Look at mine, do they look as bad? I went to a very specialized shop and they told me the only thing I can do is to get the camber adjusted to the minimum....

dantzig

J-P,

That wear pattern is much more likely due to improper toe setting than camber. Too much camber will wear the inside, but more evenly. Your wear pattern is scalloped. The rear is supposed to be toed-in, and your tire looks like it was toed-out. Improper toe will grind down a tire much faster than too much camber also.

Jon

Macster

Yes. Get the car properly aligned. With a proper alignment and absent extremely agressive driving on the street or track time tire life should be around 12K miles or more, maybe even out to 15K miles. And tire wear should be even across the tread front and rear tires.

The right rear can wear a bit faster in cars without LSD due the rear diff design, but unless you're nailing the throttle around every right hand corner you shouldn't see the difference in wear.

BTW, camber has no effect on tire wear. Both my Boxster and Turbo deliver real good tire wear, even tire wear, with the proper amount of negative camber. Toe (in/out) is a much bigger factor in excessive and uneven tire wear. Everytime I have had noticed uneven tire wear or fast tire wear it is the toe in (rear) that is the setting that is the culprit. But all 4 wheels should be aligned.

In fact once the Boxster left the alignment shop with negative camber at its max allowable setting. Alignment shop (Custom Alignment in Mountain View, CA: a highly respected shop and very knowledgeable about alignment which is why I took my Boxster there in the 1st place) told me while it could bring the camber closer the high amount of camber would *not* affect tire life or tire wear or the car's steering or handling feel. I had the shop leave the camber where it was and the shop's info proved to be spot on.

On a related note my Turbo went through a pair of new tires in around 8K miles and when I had the tires replaced and an alignment done it was rear toe that was off.

Whenever I get any of my cars aligned I always insist on getting a before and after printout of the alignment settings. This is very helpful in id'ing what alignment settings are off, but how much, in what direction and based on the tire life and wear patterns how these settings affected the tires.

Sincerely,

Macster.

jpflip

Good afternoon Jon! I went , first, to a place that I did not trust and all the readings were dead on??? So I decided to go to a specialist Ferrari, Lamborghini, Porsche and to my big surprise everything was dead on again!!! So he offer me to reduce the camber and did a final adjustment with me sitting in the car and the final result is perfect....

dantzig

OK, I believe you. My tire wear is pretty even across the rears, with stock alignment.

dantzig

While I agree with your statement that improper toe is a much larger factor in excessive tire wear, I think that the statement about camber is a little misleading. What the shop said about camber is true, as long as they were talking about within the spec.

A lot of people think that increasing negative camber will help their car handle better on the street, so I thought I'd amplify on that. Excessive negative camber will have several detrimental effects on a street vehicle:
(1) Uneven tire wear, with more wear on the inner edges
(2) Reduced braking performance because the contact patch is skewed
(3) "Tramlining" where the car will follow crowns and ruts in the road

Increased negative camber is useful for reducing outside shoulder wear under heavy cornering loads, and helps to keep the tire flat on the ground in such cases. See the figure below, taken from my DE class notes. Notice that the this is a right-hand turn, and the left tires are heavily loaded, yet still flat on the track. This is because they started with large static negative camber. Driving the car with this alignment on the street tended to produce excessive tire wear.

Jon

Macster

Yes, the rear wheel camber while very high was within spec. (Might mention the front wheel alignment was right on the money.)

If the rear wheel camber had been out of spec, or unbalanced between sides, I'm sure the alignment shop would have told me and furthemore would have advised me to let it bring the camber setting into spec. In fact it would not have to advise me to have this done, I would have insisted on having it done with no prompting.

My point was that as long as camber is within spec, even if it is at the high end of what Porsche allows it doesn't appear to have any noticable effect on tire wear nor did it have any noticable effect on my car's handling and steering. And I'm real sensitive about this.

Sincerely,

Macster.

Mikelly

I've adjusted mine to -1.2 in the rear and -1.0 up front for street driving this year. I suspect that since I don't intend to track the car much this year, I would try to keep the tire wear down... Normally my "track alignment numbers KILL tires... -3.0 upfront and -2.5 in the rear. That's way beyond reasonable for any length of street driving...

I pretty much agree 110% with what Jon's posted above. That said, I didn't notice a huge amount of tire wear when I was running the rears at -2.0 and the fronts at -1.5 with my previous Michelin Pilot Sport RIB tires... they were a dual compound and worked very well to manage tire wear.

Unfortunately, Michelin discontinued them.
Mike

adam_

"dead on"?

Does everyone know that ALL alignment "specs" by definition include a 'range'?

Unless by "dead on" they mean "precisely in the middle of the range", I'd want to know WHAT the numbers are.

Camber, schmamber... if you have too much TOE it will accelerate wear on the edges that the camber 'presents' to the road, but it is the toe that is causing that tire to scrub at an angle on that edge.... Set the camber to whatever you want, but then go to the very minimum for the toe spec.

Camber of -1.5 on the rear with a toe of 0.08 will give you 5k miles....drop that toe to 0.01, 0.02 and you will get 15k

A

Mikelly

There is a range in the Factory Service Manual. I have that range, and the manual posted over on renntrack. And Adam, you're 100% correct. Guys complain about my car being "twitchy" because I try to keep the toe in to a minimum to almost zero. But on the street I'm not driving aggressively anyway.

Mike

Macster

This might be of some value:



Sincerely,

Macster.

rnridout

Thanks for all of the replies. Yes, mine look exactly like the one in the picture. Basically looks like a groove has been cut into the inside corner of the tire. Almost looks like it's been rubbing on something, which of course, it hasn't. I'm gonna check on the "toe" setting on mine. It's pretty damn annoying, guess I'm gonna have to replace this set with very low mileage before I have another blow out, just easing around now.