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I'll 2nd the recommendation of 285 Sumi's. Great street tires that perform well and considering how cost effective they are, you should buy new fronts too. Mismatched front & rear is not optimal.
Sumitomos are really good for the money.
As op said, buy all four, never mismatch tread.
I track my car a few times a year in addition to dialy driving in summer months.
Be careful you don't purchase a tire that will not withstand cold ambient temperatures if you live in four season area.
In Upstate New York, my car sits during the winter and garage is not heated. So my selection choices are limited
I'd still like to know if 315's can be used...as far as matched sets, I don't think that fronts and rears need be the same, I have had mixed brands on a number of my cars as long as they are NOT 4 WD VEHICLES and the AXLE sets are the same.
IF I was a RACER I would NOT mismatch, but then again I have seen mismatched tires (in axle sets) on auto cross cars!!
When you consider that the front tires and the rear tires are such a mismatch in PATCH size...why do YOU not recommend it?
It is good to have similar friction coeficiants, how it sticks to the road, for all 4 tires. The factory sizes r different because u have different weight applied to the tires between the front and back. What u will find is the engineers have designed the factory sizes so that the car puts down a lb/sq-in that meets porsche performance specs. Not sure if u r new to the 911 or maybe u dont drive the car hard enough to notice, but the quircks of a high power rear engine car r unique. The thing is u can go from good to dead in these cars quickly and u dont want your tires to exagerate the issue. Also autocross cars r designed for a specific purpose and i would use very little on how they r built toward a street car.
one thing that is important even if its not a 4s is that the tires r within 2-3% in circumfrence, idealy exact. These cars get weird in the corners when the wheels dont spin at the same speead even in a 2 wheel drive car.
all this being said its your car, do what u want. There r many different tires to match your style and road conditions.
the answer to your 315s question is not that simple. We need to if your suspension is lowered, what size wheel and offset u have, year of car to see if u have to roll the fenders and if u r willing to put 2-3* of camber on the rear alignment. This will shorten the tire lifespan.
I widened my fenders by 2.5 inches .. or maybe it was 1.5 .... (would need to check my thread to confirm) and I swapped for hsr coilovers and I have about 1" of space between my inner tire and my coil spring. so 315's I think would be a rubbing issue with out rolling the fender.
I just bought Kumho Ecsta PS91. Very reasonable and they get good reviews. I got all four installed for about 1K. I can't tell you how they drive because we just got socked with $#%$%#^ snow.
It is good to have similar friction coeficiants, how it sticks to the road, for all 4 tires. The factory sizes r different because u have different weight applied to the tires between the front and back. What u will find is the engineers have designed the factory sizes so that the car puts down a lb/sq-in that meets porsche performance specs. Not sure if u r new to the 911 or maybe u dont drive the car hard enough to notice, but the quircks of a high power rear engine car r unique. The thing is u can go from good to dead in these cars quickly and u dont want your tires to exagerate the issue. Also autocross cars r designed for a specific purpose and i would use very little on how they r built toward a street car.
one thing that is important even if its not a 4s is that the tires r within 2-3% in circumfrence, idealy exact. These cars get weird in the corners when the wheels dont spin at the same speead even in a 2 wheel drive car.
all this being said its your car, do what u want. There r many different tires to match your style and road conditions.
the answer to your 315s question is not that simple. We need to if your suspension is lowered, what size wheel and offset u have, year of car to see if u have to roll the fenders and if u r willing to put 2-3* of camber on the rear alignment. This will shorten the tire lifespan.
^THIS^
Well said, if you were to do a PCA HPDE, your tires treads need to match to pass Tech
As op said, do what you want, but these rear engine Porsches are a different beast when performance driving.
Back in the 80's I imported a 78/79 Turbo...tell me about "funky" handling....then again I only use the 996 for top down cruises ... and Porsche social events...
03-04-2019, 01:01 PM
