willr

I see that Michelin now produce both 225/40ZR18 and 235/40ZR18. Only the 235 size tyre is "N-rated".

Several people posted that they use 235/40 fronts. But since the OEM front tyre size for a 996tt is 225/40 and since this matches the rear (295/30) PS2 revs/mile better, should I go for that instead?

wross996tt

You need to match the diameters as best you can, so if you go 235/40 you should get 315/30.

Spec Sidewall Radius Diameter Circum Revs/Mile Difference
225/40-18 3.5in 12.5in 25.1in 78.8in 804 0.0%
235/40-18 3.7in 12.7in 25.4in 79.8in 794 1.3%
295/30-18 3.5in 12.5in 25.0in 78.4in 808 0.0%
315/30-18 3.7in 12.7in 25.4in 79.9in 793 1.9%

willr

Has anyone actually used the 225/40-18 PS2 on their 996tt, in combination with the 295/30?
As it's not "N-rated", I'd like to hear some positive feedback before buying!

Kiko

I did and actually have a set of n-rated PS2 235's with 600miles on them sitting in the garage. Although they're within the 3% (PNA says so...) I found but PSM and ABS became ALOT more sensitive and edgy so I took them of and went back to 225 but (as in many other mods like 2WD, etc) I'm the exception since there are many please 235 users.

willr

Good to hear, Kiko.
My car is totally unmodified, but after a few years running Pzeros I've decided to change and would prefer PS2s over the other options. It seems that Michelin do two versions of the 225/40-18 PS2: One is OEM for Audi and Daimler, the other OEM for Mercedes. They have different part numbers and one is slightly wider than the other. Which did you get?

Kiko

I didn't know that...how do you tell them apart?

Please beware that you're bothered with softside walls just pick another tire like Bridgestone SO-2A's, PS2 are extremely good tires on the wet and dry but make this wallow at speed specially in the first 1000miles.