SwedeCT

Hi,
I just bought a set of Hollow Spoke wheels and brand new tires came with them:

Michelin PS2
Rear: 295/30-18 98Y XL N2
Front: 225/40-18 92Y XL no N-marking

Should I just:
a) mount it all and be happy, or
b) ensure I get N2 tires for front as well (and maybe 235's to 'match' the wider 295's in rear), or
c) use my current front tires (N1 marked and tread left) and mount the new 295 N2's in rear.

I've read about the importance of having same N numbers all around, but wonder how critical it is and if anyone has had good/bad experience with combining N and non-N extra load tires ?

Thanks!
Peter

kjr914

Search a bit for "N rated tires". This has been discussed many, many times. You'll find opinions on both sides...

cgfen

i choose A, but going to 235's is a good path if you do decide to keep your N's together

be happy

flatsixforme

This is of course my unscientific opinion but I think the "N" rating boils down to max load and sidewall stiffness...all that extra weight in the back of a 911 really induces a lot of rollover/sidewall flex. To counteract this one has to add more pressure to a non-N rated tire during track/spirited driving to reduce excessive rollover...which in turn reduces the contact patch and thus overall mechanical grip. So, N-rated tires (IMO) have stiffer sidewalls to allow the spirited driver to run optimal tire pressures to maximize the contact patch and not get excessive rollover.

Bottom line for you, I would just run the mixed set if it were me, especially because the non-N rated tires are the front. I would just keep in mind that the softer sidewall in the front will act like a softer "spring" in the front giving additional grip relative to the rear. You could run a bit higher pressure than normal in the front to counteract any sidewall flex and at the same time dial out any oversteer you might have entered into the equation. Note, the shift in balance of the car really won't be noticed unless you are at the absolute limit with the car. Find a little "skidpad" safe parking lot and test it out to be sure.

Hope that helps!

SwedeCT

Thanks guys for valueable input.
Im sure it'll work with the new set I got (option A) but will sleep on it over the weekend.
Called a few Porsche specialized tire dealers here in Sweden and surprise - they all said different things...from dont worry, to make sure front/back have N marking (even if they are different..), to only go with same N markings... Then the fact that the new rubber is 295 rears but still 225 front (Ive read some move up to 235 when going 295 rear..). Oh well, I'll let you know if it doesn't work out for info sake. cheers