Long story short: I called TireRack for snows for the 2007 C4S. They recommended 265/40R18's for the rear.

Today I was reading in the car's manual for something else when I stumbled on p. 332 where it says that Porsche only recommends 295/35R18s for the rear on the C4S (in an 18 in fitment). The 265/40R18 is only for the C2S.

Unless I'm missing something, I take this to be a tirerack screw up. Anyone able to make sense of this or are the tires going back?

Thanks...

 

call Damon and ask him...

 

Indeed. I actually ordered them from him!

 

A C4S that parks in the same parkade as I use at work has 265-18's (10" wide rims) for winter use. A narrow tire will generally give better grip in snow than a wide one. Its certainly not a weight limit issue (~100lb difference in max loading depending on brand/tire).

 

Good to know that that combo has blown up the center diff yet

 

I guess it would depend on the actual make of tire, but as an example the Michelin Pilot Alpin winters are:
265/40-18: 790 revs per mile
295/35-18: 797 revs per mile, not much difference. (Actually is the same revs per mile as the summer PS2's in the same sizes). What really matters as you know is the revs per mile between front and back - not sure what the max % difference is on a 4.

 

I have Michelin Pilot Alpin 265s on 18" Carrera III wheels on my 2007 C4. This is my second winter on them and I have had no problems. They don't look as good since they are stretched more than the wider tires, but are fine functionally. You can always buy the 295s if you prefer, but narrower is better for snow. During the summer, I run PS2 305s on 19" Turbo wheels.

 

I am running the Conti ts810s in 295 rear and love them. I drive in snow alot here in Colorado and they are very predictable. I got them from tire rack last year, but noticed people were having a hard time getting them this Fall.