Rear tires are are worn out and thread is showing onnthe inner portion of the rear tires at 25 k kms. Is this normal? Reat of the tire still looks ok. Checked alignment and its spot on. Is this normal, why does porsche not engineer better setting so the tires wear out more evenly on the rear, is this due to normal camber setting or a bad toe setting?

 

center of the rear tires should wear faster on 911s. i have not seen inner side wearing faster. it's sign of too much negative camber. maybe tire pressure is too low?

however, 25k km (16k miles) is definitely due. usually, rears are due at 10-12k miles.

 

I was told that I had 50% tread left on my C4S at 9,890 miles. At 10,000 miles (16,000+ kilometers) I could see the steel belt on the inner tread surface of both rear tires! Glad that I did not take the intended trip.

4-wheel alignment showed more-or-less normal specs for the car.

 

I got 12K miles before the change. wore even across.

 

some say you should drive a porsche always like a porsche to get even wear. cerbo must be doing something right. however most say that 16k m is just right.. how can i get 16k with one side wear, maybe due to wrong alignment, and cerbo 12k evenly worn out tires...

 

Is your car lowered ?

 

14000 mi. on my current set of MPSS and they still have plenty of life. F/R -2.5/-2.0, 34/37 psi.

 

The rears wear a lot faster than the fronts Went through two sets of Michelin pilot sports rears over 30K miles. Fronts still had tread left. Switched to Michelin pilot super sports at 30K miles, now at 50K and the rears are getting close to the wear bars. From what I have read in this forum, the mileage is normal wear. it's the price you pay for the grip. The uneven wear however is not.

 

Slickly Rick...

You have a bad alignment on your car. Take it to a race shop and tell them what you want.

1) the factory builds in some toe angle into the rear of the alignment specs to help the average driver. This is adjustable. You will see this illustrated by the rears wearing out much faster than the fronts. (Read about this before deciding to move outside the factory specs. There is a reason the factory does this.)

2) as you lower the car (sport springs) the negative camber in the rear gets out of control fast unless you adjust for it. (Sounds like your issue)

It took me 4 alignments in 2 years, lots of tweaking and some pro help to get mine the way I like it. Mine has very little rear toe. Less rear camber than spec, has the X73 suspension, adjustable sways, and adjustable rear toe links. Playing with this stuff is not for the faint of heart.

My tires are wearing very evenly, the handling is very good and I have less Understeer than the factory dials in. I also like the throttle-off oversteer. It is very predictable and fun. But you better have fast hands!

In retrospect I would never suggest anyone go down this road. Good luck.

 

Car is not lowered all factory...but still reading our brothers suggestion

 

Bottom line- the tire wear will tell you the issue with the alignment. Good luck.

 

My old tires (P Zero Rosso) wore pretty evenly, but I noticed the inside of the front tires had 1 mm less tread left compared to the outer tread.

I just put on a brand new set of Michelin PS2 tires and decided to measure the tread depth. To my surprise, the new PS2 tires come fresh from the factory with 1 mm less tread in the inner most tread on all 4 tires. So it seems to me that even with perfect alignment, the inner tread depth will always be less than the outer tread, making it seem like there could be more inner wear than normal.

Can anyone comment on this?

I'm wondering if having less tread on the inside is part of the Porsche N spec design or if it's just the normal design of the PS2.

 

I've got 10k on mine, only a couple of more thousand left , wear is even, but there is an old industrial park close by with a bunch of curves, I could change all this in about an hour!

2:1 rears to fronts.

Good luck.

 

Yes, that may well be normal. Given that the alignment is correct, tire life depends on the tire, the roads you drive on, the type of driving you do, and your driving style. Nobody here can judge any of those things on an internet bulletin board. Regardless, 25K km (>15,000) miles on a performance tire is quite reasonable.

 

Look at any race car, and you'll see significant negative camber in the front, and some in the rear (assuming independent suspension). This is used to keep the full tread of the outside tire in contact with the road under hard cornering. If you're not cornering really hard all the time, you'll end up wearing the inside of the tires more than the outside. Most performance cars adopt the same technique, though to a lesser degree for street use, so this is pretty normal.