louie007

Hi guys i want to change my rims on a 06 C4S right now i have the stock lobster 19x8.5 front and 19x11 rear , now i like the big azz what would be the biggest i can go 20x12 duable on the rear this is just for pleasure driving no track , and without damaging the big beautifull azz , thank you

gota911

Stay with 19" as the 20" will be a very harsh ride because of less tire between the wheel and the road. You could probably go 12" wide with the correct offset.

Check out this tool: Wheel Width & Offset calculator

louie007

thank you , great tool but if i stay with the 19 x 11 in the rear and 19x8.5 in the front ,i like the look of the tire beeing flush with the body as it is a wide body can you recomend what size of spacers maybe you have had experince with this , thank you very much

kosmo

you can def go 11.5 wide on the rears. Unsure about 12s tho.

Farfelc2s

I have 20 x 12s w No problems at all, flush as well.

sandwedge

My rear Champion RG5's are 19x11.5 and 7mm spacers bring the tire exactly flush with the fenders. Actually, the lip on the Bridgestones goes slightly outside flush. Close enough. For the 19x8.5 fronts, 5mm spacers do the same thing. You can't apply this to any wheel though since the offsets vary. Buy the wheels you want, mount them and measure the void. Those are the spacers you need.

For 997 wide bodies I've seen others with different wheels getting the same result with 7mm rear and 5mm front so that setup seems to work with a variety of wheels on this car.

mdrums

8.5x19 front and 12x19 rear work great. Don't do the 20" wheels on this car. You can get the flush look with the wheel offset.

Your C4S is a widebody so you need the following offset and the wheels will sit right and be flush and safe to drive on the street.

8.5x19 et53 offset 235/35/19 tire
12x19 et48 offset 305/30/19 tire

louie007

thanks for the info, great forum

Edgy01

Largest OEM wheels would be the 19x12 rears from the GT3.

TJ Elliott

Like most things with our cars aesthetics and ride are subjective so you need to make your own assessment. For the street I run 20X9 front and 20X12 rear Techart Formulas on my 07 C4S (19" for the track) and I think they look awesome. My tires are 245/30 on the front and 325/25 on the rear. I also have H&R lowering springs. The wheel wells are filled out very nicely and I have no rubbing issues.

In my opinion, the ride with the 20's and lowerings springs is totally suitable for street. My wife approves of the ride and we have no problem doing 8 hour drives without complaint.

As I said, it's totally subjective. However, don't let anyone tell you it shouldn't be done.

Enjoy your ride!

gota911

Actually, he would want GT3 RS wheels because, like his C4S, the RS is a wide body and the offsets are appropriate for a wide body.

Ynot

I have the same setup and it rides fine wrapped with PS2. I had 19" wrapped in toyo's before that and can't say I notice any difference. Tires and road conditions makes a huge difference. The only problem with 20" are tire choices, you have 3.

GentlemanRacer

I am considering adding either HR springs or Bilstein PSS10 to my 2010 C4S.
How different is the ride height from stock and does the springs affect PASM?

Thanks

pissedpuppy

FALSE. and I mean totally false (no offense). I moved to 20s because they just looked beeter in the wheel well. It had NO bearing on ride quality (a few years back they were saying the same about going to 19s). It just had NO bearing on the quality of the ride at all. pic attached

gota911

No offense taken and I am glad your ride didn't change. However, one example doesn't make my statement false.

I have ridden in a few cars (both 911 and non-Porsche cars) that had "upsized" wheels and most, if not all, of them rode harsher than the stock wheels.

I also think tire pressure has a lot to do with the ride. Many guys who "upsize" their wheels will keep the pressure high to give them "enough air and firmness" (quote from on ower) in an attempt to protect the wheels from pot holes. Tires with maximum inflation ride harsher that those inflated in the normal PSI range.