Tire wear, what's normal?

So, since I bought my car, I have put on about 8k miles. The car came with what looked like a fair bit of tread life. Today, on the way home from SC to NY, the back tire (s) started making a really loud noise and vibrating. I stopped about three times, checking the tire pressure and twice, they needed air. Then, the last stop I got on the hands and knees and what I saw shocked me. The inside half of the rear tire treads were bare, on both tires. Bare, I mean slick. I did 55 mph home for there. First, yes I know I am an idiot. Next, do all 996's have such a degree of toe in, that tire wear is always uneven? From the outside, the tires look like they are almost new! Thanks Tires I am considering. I would like them to be good on the track. The Eagles are said to be bad track tires. FGoodrich g-Force T/A KDW 2 Goodyear Eagle F1 GS-D3 Bridgestone Potenza S-03 Pole Position Goodyear Eagle F1 GS Michelin Pilot Sport PS2 Michelin Pilot Sport Rib

Yup, that's normal. 10,000 miles are about average for good tires (rear) on the street. You might get 3 times that on the fronts.

I actually thought the camber did that to tyres, am I wrong?

I pushed my rears to about 17K miles, then I swapped them for the winter set. Next spring I'll have to "spring" for new rear tires. Definately add $1000 year to the TOC if you drive the car 12K+ a year.

There you go...assuming again....

It's Camber.

I either must be very lucky or drive like an old fart bc I have alot of tread left on my car.. 7k miles and ticking..

I have P zero-assymet., I got 15k out of the rears with track time, 24k from the fronts, they are totally shot now. The new rears have ~9k on them and have plenty left even after 4 track days alone! I actually didn't buy snow tires, if it's that bad I take alternate transportation, it's not me I worry about, rather the other idiots. Besides if I'm going to have a set of rims clogging up the garage generating flack from the wife, they're gonna be track tires!

My experience has been about the same, i.e. maybe 12-15k on the rears, much longer on the fronts. I had Kumho's on the Boxster S, and for street only use they were decent and have a longer life. Problem is, in L.A., lately it doesn't seem to matter, due to potholes I had to put 2 new tires on the Targa in June at 1,900 miles, and last week I had to put a one new rear on the 997S at 3,500 miles.

You should check alignment. Find a shop who knows how to do Porsche alignmenyts right. Also, only buy N-rated tires and the same brand on all 4 tires.

Too much negative camber will wear out the insides. If I'm right, too much toe in will cause the outsides to wear. If you had too much toe out, you'd know it. It would be terribly squirelly. I would say that 8K to 15K is normal depending on how hard you drive. Your choice of tires is somewhat limited by what sizes you want to run. What do you have now? I don't care about N-ratings, and mismatched F/R is OK within reason and if you know what to expect. A lot of folks don't run stock sizes or tire pressures, either.

Wow, thanks everyone. I am not sure why I said toe in, its clearly not correct. Its good to hear the tire wear is nothing way out of the ordinary. I have a set of winter wheels that are going on this weekend, and I will have a P-car alignment done to make sure everything is good. All in all, now that I am back I am happy to get rid of the Dunlops 9090's. I hate them. I have not seen a single 996 owner use them, but has anyone ever tried FGoodrich g-Force T/A KDW 2 on their car? I had them on my S4 and they were amazing. Apparently, they are pretty good on the track as well. Any thoughts? Once again, thanks

I get that same inside wear pattern, but get more like 20,000 out of the rear tires. I get about 30k out of the fronts.... I think the mileage is more closely attributable to the durometer of the rubber, assuming the alignment is close to spec.... Re the wear pattern, I have been playing with toe and camber to see if I can get a better wear pattern. since I only use the car for commuting, I don't set performance as the number one objective.....Still, it is unnerving to think you have a good set of tires only to find cord showing on the inside shoulders.......

The inside normally wears out first because under acceleration the rear end squats a bit and they are under negative camber, but if your outside looks like new then you might have a misaligned car. The average for rear tire depends on how hard your car is driven. Very aggressive driver average 10-12K and more normal driver get 15-20K. I suggest you make sure to get a good alignment. As far as tires the the KDW are more of an all weather tire, the KD is the better track tire but wears out fast. The Eagles are great street tires, but not as good track tire as the others. The Pilots2 are the best tires for track and wear but are costly. The S03 are a good tire with a little less grip than the PS2 but are heavy tires. IMO get the PS2 if cost is not a concern, the S03 would be my next choice as they handle good. last relatively long, and cost less. The weight difference is a concern, but unless your a really good driver you probably won't feel it.

I run a better traction (softer rubber compound) than many 996 drivers. I know the P-zero's (which have considerable less traction) have a harder rubber and may last alot longer. The Bridgestone RE750's are the best traction tire I have yet found for the street.

On my old C2, I'd get 10k miles on the back and 20k on the fronts. Go for the PS2's. I'm really happy with them. Better than S03's or P-Zeros. Be sure and get an alignment done too.

Forget the allignment unless there are signs of uneveness in wear between the 2 back tire or the 2 front tires. I just had new tires put on my car and the allignment checked at 45,000 miles. Still within specs. Unless you have hit something or had someother incident that would cause the suspension to be jarred hard, your alignment should last you years.

Do the alignment. I had mine done after a few years and the only thing that was off was the rear camber on both sides (by the same amount). From what you're telling us, your car may have too much negative camber also in the rear like mine did (where it drives fine, but chews thru tires prematurely).

A PROPERLY alligned 996 will always wear the insidr half of the back tires. It has a negative Camber purposely. Mine is -1 degree 10'

Yes, the back has negative camber. Mine was off more than 1 degree when I got it aligned. It's beneficial to have it set correctly. Too much negative camber for a street driven car will wear the tires excessively & prematurely on the inside.

How are the PS2s relative to SO3s in terms of tire noise and wet grip?

Normally I would not bother with an alignment with a new set of tires unless there was abnormal tire wear. However, when I had my alignment specs changed this year some of the settings were way off after about 2 years of normal street and track use. I now believe that the city streets really take a toll on the suspension settings and I would recommend an annual alignment on all Porsches.

I don't have a lot of miles on my PS2's, but I understand they get louder as they wear. No problem so far. Haven't had them out in the wet yet, but in the dry and on the track they seem much better than S03's.

Make sure that if you get an allignment you have the shop print out all specs BEFORE any any adjustments are made and then after the car is alligned.

Since your all on and I am having a hard time searching for it. Do you know what or where I can find the "correct' alignment specs for a 2001 C4? Since many of the Porsche specific shops appear to be closed this weekend, I might be forced to go to a chain and would like this handy. Thanks CJ

Tell us why you decided to get the allighnment? Is there $150 burning a hole in your pocket? Or is there some specific problem you have with the steering or tire wear? I got a 1994 Honda in the garage that has $123,000 miles on it that has never had an allignment. Age of car and mieage do not by themselves cause a car to go out of allignment.

Well, I guess I don't know if these are major tire wear issues. I didn't get on my hands and knees when I bought the car used and test the inside of my tires for tread thickness. This is my first Porsche 911 and was unaware that the rear tires wore out like this. So, before I spend $1,000 putting new tires on the car and burn through a set of new $600 rear tires to find out I do have a problem. I think I will spend $150 bucks to make sure its not an issue. One thing that makes me think there might be a problem is that the car was on the dealer lift about a 3k miles ago. Being there is such a large markup by the dealer on tires. If there was a need for tires, I am sure I would have heard from them. So, if 3k miles ago they were not bald and they are today, then that sounds like a posible problem of my dealer missed the boat. Also, I live in Brooklyn and I drive in New York City and the surrounding areas. If there is any environment that will cause your alignment to go out, this is it. I know your roads are tough in Chicago, but you just have no idea! I used to get my alignment done once a year on the S4 and each time its was required. I will try and get some pics of the tires after they come off and also get the before and after measurments on the alignment. Thanks CJ

Ok, if it gives you piece of mind. I grew up just outside NY and used to date a girl in the Bronx. Tough roads. Tough girls. But if you are concerned with the inside half of the rear tires wearing to almost the belt in 10,000 miles or so, this is NORMAL and will continue to do so even after an allignment.

It depends what tires you are running and the kind of driving you do. The harder rubber tires will last longer. The more open road driving and highway driving you do, the more the inside of the back tires wear. If this is the kind of driving you are doing and your back tires are not worn more on the inside half, then YES your allignment is out of spec. The negative camber dictates that the tires wear this way when primarily drivien straight especially at highway speeds. Trake driving will result in different wear.

I final update. The car went up on the lift and the tires were more worn than I thought. So bad that the steel wires were poking through! Thank god they are gone and the 17" winter wheels are on, giving me time to deliberate on what summer tires to get. Should I go 265, 285 or 290 , so many choices. Anyway, the rear alignment was WAY OFF!! Here are the specs off the Hunter DSP 600 laser alignment system: Rear left After Before Specified Range -0.9 -1.8 -1.4 to -0.9 Camber 0.22 0.36 0.08 to 0.25 toe Rear right After Before Specified Range -1.1 -1.7 -1.4 to -0.9 camber 0.19 0.43 0.08 to 0.25 toe As you can see, the specs are way off and the winter tires are on. Thanks all for your help and I will post a pic of the tires if I have a chance. I am also a little embarrassed. Also if there is anyone in the NY tri state area would like some relatively unworn Dunlop 9090 18� fronts, they are yours if you want to pick them up.

Good call to get the alignment. Get the 285's on the back, it really is the proper size. Mine came with the 265's and it always looked a little strange to me. I was much happier with the 285's.

I must drive like a weenie or something. I have Continental Sport Contacts that PO put on the car. They have 12k miles and the rears still have 7/32nds tread. Fronts are a bit over 8/32nds. Are Contintental hard tires? I have already bought a set of Toyo T1S' off ebay really cheap, but have had no need to replace them yet. Are the Toyos softer?

I use Toyo's (and Conti's and P-Zero's) to for bumpers on my dock to protect my boat. If you want the best traction street tire, go with the Potenza RE 750. I have tried the rest and there is no comparision in traction. Hot or cold. Wet or dry.

I run Contis, chnaged my rears recently. I am happy with them. I will chnage my fronts and do allignment when the car comes out again in march.