brad@tirerack.com

Buy one matching rear tire shaved from us to the appropriate tread depth of the other side. Finish wearing them all down and then buy a new set. I'm glad to help when you are ready.

Hurricane

porsche42

Same situation I had. 4k miles and got a nail. I just replaced the one tire with another P zero.At 17k miles replaced all 4 with MPSS.

AAK GTS

Great idea to just buy the one and have it shaved.

chuck911

Wonderful.
I had a student somehow make it through tech with mismatched tires. He was just like you, oblivious to the hazards of running totally mismatched rear tires. Actually not only oblivious, but like you actually believing wrong is right. Also like you same faulty reasoning- I've done this lots of times!
So I'm sitting there sweating it out as this clueless student has no idea how close to mayhem he's coming lap after lap. Even tried several times to point it out to him- "did you feel that? Didn't you notice that? Etc."
Some it seems learn easy, some not so easy. Finally one lap he goes just that little bit beyond and ..... before he even figures out what's going on I said, "Both feet in."
Because only very rarely is obliviousness confined to one area of life.

Hard or easy. Choice is yours.

erko1905

+1

Mismatched tires on track - just thinking about it gave me anxiety

Churchill

I would read my post a little more carefully, my friend. I said it's fine to use different tires so long as you use the same tire on each axle, and so long as all of your tires are the correct size and spec. Of course one should absolutely not use "totally mismatched" tires.

I'm curious to hear from the peanut gallery what, exactly, they think would happen to a 991 that has for example factory approved Pirellis on the front and factory approved Michelins on the rear. Does the car burst into flames? Do the Michelins lose all their grip because they know Pirellis are on the front, or vice-versa? We're talking about tires with 98% identical grip characteristics, on a car that in street driving doesn't approach 75% of it capability. The fact is, the difference in tire performance between factory-spec 991 tires doesn't even come into play in street driving. Which is why it's fine to have different rubber on the front than the back.

I've run different R-comps on axles of my track car. I had Sumi HTRZIII's on the back of my 993 for years while the HTRZII's wore out in the front. No trouble at all. I am curious to know how I've managed to escape catastrophe all these years.

hbear

tvad

On my 2014 CPO 991.1S the front Pirellis were manufactured in 2013. They have good tread remaining (not down to wear bars), but they have cracking around the outside edge of the tread. Keep or replace?
Rear Pirellis don't show similar cracking and were made in 2015. These seem like keepers for sure.

If the advice is to replace the fronts, then replacing with Michelin PS4S is OK while keeping the Pirellis on the rear?

goldduster

Can't advise on different front and rear, but you don't want to drive on cracked tires. Three things I don't fool with are; Tires, Brakes and Steering!

aCayenneFan

+1.

HelpMeHelpU

This, from a man who sells tires.

What more do you need to know?

4 Point 0

As the OP said, he will not track. This tends to imply that he doesn't drive his car anywhere near its limits. So having two Michelins on the rear, he won't know any difference at all, as you suggest, it will be fine.

I have experimented before with MPSS and MPSC2. I just bought the rear first in super sticky MPSC2. This was on my M4. The difference was traction control. Their was so much extra grip in the rear, that the traction control was over active. (Its over active in BMW anyway. I never see it in the 911) So really the only thing is creating more understeer or Oversteer. That is all that will happen when you run a better tyre on one end or the other. If you are not tracking and drive at the speed limit, you would never notice. If you drive hard, you should already understand the difference between oversteer and understeer and may have even done it deliberately.

End of the day, its no big deal, as long as both rears match each other, and both fronts match each other.

If you drive hard you can't go past MPSC2. I will put them on my GTS really soon! As OP doesn't track I second that MP4s will be more than you will ever need. (I personally don't like the Standard P Zero. But I drive fast and I track.) They should have come with Corsa or Trafeo R but then they would be GT3 Killers : )

Fünfer

I ordered just one P Zero to match the rest of the tires already on the car. I was planning on getting it shaved. But is that even necessary?
One of the rear tires would be new. The other has 6K on it. Will the difference cause any issues?

LexVan

Need to measure the "old" remaining tire. A new rear tire is 9/32's. Hopefully the old one is still +6/32's. If the delta is more than 3/32's...shave the new one down 1-2/32's.

Everyone (car enthus) should own one of these: