Jim 'n' SC

How long do you go before buying new tires? My rears are down to 4/32 and the front are at 7/32. I'm not going to buy the same tires so I can't change just the rear. Tires are three years old. Thanks.

alexb76

Just check both INSIDE and outside of rear tires, typically inside wears a lot more, so you might be 4/32 on the outside, but 2/32, 3/32 on the inside.

I'd change at 3/32 in rainy cities, and may goto 2/32 if you were in nicer climates (like southern CA, AZ).

sandwedge

For the rears, I wait till wet tires leave rust marks on the garage floor.

Chaos

equ

You clearly and simply need rears. Which tires are they and what don't you like about them?

cvazquez

I still use the penny method. I'm old fashion, I guess.

gota911

You need to move up to a nickel...... to cover inflation.

gota911

Jim,

Your rears are probably very near the end. It is not worth trying to squeeze an additional 1/32 or 2/32 out of your tires.

We need to meet for coffee some morning. I have yet to meet another Greenville Porsche owner and would like to meet you and see your silver beauty.

Jim 'n' SC

I'd like that Tim. I sent you a PM.

aaks38

2/32 is usually the legal limit in the case of inspection. Someone else noted that rain is a determining factor so 2/32 is the lowest you want to go. Im actually running on 2/32 but i only drive mine in the dry weather and im keeping an eye on it but then again my tires have a treadwear rating of 280 and ive gotten 20k out of the rears.

Most people whom track there cars actually prefer low tread height as it doesnt deflect and introduce tread squirm.

steph280

For some reason my factory Rosso rear tires wear on the center. I do watch my tire pressure and it was never overinflated. The thread just seem to disappear while there are still plenty of rubber before getting to wear bar.

This is what it looked like when I swapped it at 7000 miles.

mk85911

I have been told that wear in the center is caused by underinflation because underinflation permits centrifical force to distend the center of the tire too far out.

Steven B

????

Do not understand this.

Macster

Underinflation can cause center tire wear becauset the tire can grow from centrifigual force and the tire growth is not uniform. Watch a top fuel race car going down the track for a very clear picture of how tires can grow under extreme conditions and note too how the flat tread face develops a crowned shape.

However, when I noticed this with my Boxster I played with the tire pressures and there was no change. Then it dawned on me the car was simply not being used at the speeds at which underinflated tires could experience center tread wear.

The center tread wear is normal for some of these cars (based on my experience with my Boxster and my Turbo) and I suspect for all of these cars since they all use similar suspension setups. In some cases I believe the agressiveness of the driver can affect how much the tires wear in the center, but regardless of the style of driving, the rear tires will wear a bit faster in the center of the tread.

About all you can do is ensure the tires are properly inflated and the car is properly aligned.

Tire wear should be even side to side and across the tread face except as I mentioned above there can be a bit more wear in the center portion of the tread and the right rear tire can wear faster than the left rear tire.

The center wear is as I mentioned above an artifact of these cars while the right rear tire wearing faster is the result of lack of LSD coupled with a driver who is a bit more agressive in driving the car, especially around sharp corners.

Sincerely,

Macster.

Edgy01

Ever since Porsches began to be offered with low profile tires owners have failed to understand the criticality of the inflation pressures. Over inflated tires lead to worn centers. UNDER inflated tires lead to worn centers--as Macster outlines above.

Using the TPMS can help you to keep your tire pressures consistent. This is important to maintain the best possible tire life.

How you drive your car is equally important. Many complain rightfully about the inside wear on the their rear tires--due to the negative camber. If you aggressively drive your car you will wear your outside edges at about the same rate as the insides wear.

Once you have chosen to own a Porsche you can't suddenly economize on tires. Tire wear is a fact of life for a high performance sports car--particularly a rear wheel drive Porsche. You are subjecting the rear tires to significant stresses that most tires cannot simply support. You have 60% of the car hanging over these rear tires, while you have widths that are approaching that of a steam roller.

When you go in an alter the geometry of your suspension to eek out a bit more mileage on your tires you are giving up handling--and superb handling is what Porsche 911s is all about.