I would appreciate some feedback for the following problem:

2006 Porsche 997 Carrera 4s
Modulare M3 20" Aftermarket rims
Current tires: Pirelli Pzero Nero x 4
Front 245/30/20
Rear 325/25/20

Problem:

I Immediately need to replace both rear tires and found out they are unavailable for purchase/order across N. America
Question: Is it okay to put a different brand tires on the back, same 101Y rating, same specs, but the pattern would be different.
ie: Michelin or conti's
This is an all wheel drive vehicle, I would like to be sure.
I just replaced the front set of tires very recently so don't want to have to replace all 4

 

...you should replace all four tires... Especially on a C4.

Others may tell you if just the rears are bad and the fronts have 80%+ then only do rears.

That said, I would not mix and match brands and/or tread patterns/specs.

I would match exact brand & tread /pattern/specs at the very least.

Consider that tread compounds, belts, belt patterns and build will differ across brands.

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FWIW, I mixed brand and pattern on my Targa 4S a couple of years ago (installed newer PS2's on rear and left the original Pirellis on the front). Never had a problem in 10,000 miles, including autocrossing. To me, any difference between front and rear tires of different brand/pattern is likely no worse than the difference between partly worn fronts and totally worn rears of the same brand (which is a common phenomenon on our cars given the faster wear of the rears). Just my opinion.

 

I think the biggest place your asking for a problem is in the rain...

 

It rains a lot here in Vancouver

 

Yeah, I agree that in the rain (or any slippery surface) you're more likely to hurt something. Would you rather spend $500 on a couple of new front tires you don't need yet (really $250 since the current ones are half worn I assume), or a few thousand to fix a blown diff?

Yes, you can run different, but I just wouldn't recommend it. If you do end up doing it, then pick something with the exact same treadwear index and a similar tread pattern to what you have now.

 

I agree, but again, driving with (matched) front tires with 30% wear and rears with 60% wear will also introduce problems, and I have to believe that my rear is safer with newer unmatched tread than with worn matched tread. I figure that in rain, I always have to be careful no matter what tires I have.

 

You can have different tread patterns from front to rear, just not from right to left.

The only time you'll notice this, is when you lose traction (which doesn't really depend on the tire, as much as it does the conditions). But even then - when I lose traction, it isn't all four tires at the same time, it is usually one or two tires that loses traction, and the then LSD, or differential kicks in anyway.

As long as your rolling diameters are within spec, I see no issue whatsoever.

 

Good reading:

http://www.tirerack.com/tires/tirete....jsp?techid=26

 

Probably going to replace all 4 tires, any thoughts on continental Extreme Contacts?

 

i read somewhere that a new generation of PS (PS3 ?) Michelins is pretty good.

never heard anything about contis in 20". they are not bad I guess.

if you would have 19" I would say - RE11 but in 20" - no idea.

 

Not an expert on tire,but do think keep tire brand and type with constancy is not a bad idea.

I used to run on PS2,but right now i am running on brand new RE11,it's good tire already in Winter(i drove 300km just couple days in sunny Vancouver),and will not doubt its performance in hot summer with more grip. And for Conti's,i have no clue,but i think they will not do you harm.

 

I ordered 4 new tires, better safe than sorry as i didnt think it would be a good idea to chance a problem with a nice car over a little bit of money and also can only imagine how it would affect aftermarket (warranty) service contract eligibility if had to make a claim

 

don't mix and match !!!!!!

 

Another good Tirerack article, this one titled
Matching Tires on Four-Wheel Drive and All-Wheel Drive Vehicles



http://www.tirerack.com/tires/tirete....jsp?techid=18

Bob