dcsjc

I need new rear tires for my 2004 C4S and plan to replace them with the same tires I've always used and been happy with: Michelin Pilot Sport PS2's. So I'm surfing the internet and comparing the various prices and noticed on costco's website they had two different choices for the same size tire 295/30ZR18/XL (98Y). Drilling down a bit I found there were two different Mfr P/N's, 39489 and 24923, and two different tread depths: 9.5 and 8.5 respectively. Surfing the internet a bit more brought up this document from Michelin:All specifications for the two P/N's except for the tread depth are identical, incl. the tire weight down to 4 significant figures: 26.57lbs (despite the tread depth being different!).

I couldn't find Mfg P/N's listed for the same tires from any other distributor (america's/discount tire, tire rack, etc.)

I found all of this curious and thought I'd share it with you.

Mbren1979

The only differences i found were the tire with 9.5 as the tread depth is porsche spec N3 and the tire with 8.5 is porsche spec N4. N4 being the newer spec if you are not familiar. Beyond that may require an email to Michelins tech support for answers. However since they are both porsche approved tires - whichever you can find cheaper sound better!

dcsjc

Ah, interesting that the difference is N3 vs. N4. I wonder why they reduced the tread depth...

Mbren1979

Trurhfully i have no idea. But i have seen before where they change tread depths due to handling issues. Believe it or not, too much tread causes a vehicle to wander at high speeds.

808Bill

Tirerack + Amazon prime = Best value!

9964runner

I think the actual tread pattern is different also, when I replaced a set of rears last year if it wasn't for the PS2 molded into the sidewall I would sworn they were a different tire.

dan_189

I'm about to buy bigger Michelin's for a new set of rims I have coming to replace my current PS2s, I have found the N3 are more expensive than the N4 too

Also don't quote me but in my case the speed index went up on the 3 vs. 4