mdrums

Gawd, I need some education and serious help really fast. I have to make a decesion by this weekend for an upcoming DE. I thought I had it all figured out but I really do not. Seems when I call wheel shops they are even confused and I get a lot of conflicting information! I need help in picking the proper tire size for my DE track events and autoX's.

Car:2006 Carrera S (997S)

Stock wheels Tire sizes I have been using:
Carrera Sport Wheels
8.5x19 55mm offset
11.5x19 67mm offset
Michelin Pilot Sport 2
235/35/19
305/30/19

The car has been aligned to -1 camber front / -1.5 camber rear. The car understeers but my local Porsche race shop, Dave White Racing now called Vortex says they can fix up my sort of stock alignment a little for me.

I want to change to 18" wheels and Michelin Pilot Sport Cup tires for DE and autoX. I will swap out the wheels in my garage before each event and drive to the event with my track wheels/tires set up.

I am looking at either Volk TE37 (forged) $2656 or OEM Carrera III (cast wheels) for $1800. the offsets are really confusing me.

Volks @tire rack:
8.5x18 49mm offset
11x8 60mm offset

Carrera III @wheel enhancement:
8x18 57mm offset
11x18 51mm offset

Which Tire size should I get for the rears??? The Sport Cups do not come in a 305 size.
305/30/18 or 295/30/18????


HELP! Mike

NJcroc

the offset on the carrera III wheel is a wide body offset it will stick a bit out of the fenders of your car. the offset refers to how far off center the whhel meets the rotor. higher numbers go further in, lower numbers stick further out. since you wrote it i assume you mean a 315 not a 305 in your question and that is a great choice with the 235/40/18 fronts

GT3CAR

Mike
I thought you just got a new set that I saw on your car last weekend (see below)?




Just bustin your chops man!!!!!! Good question. I am glad you asked it as I am confused by the off set as well.

See you in sebring on 9/7 & 9/8?
I will be there the next weekend too.

Lindsey

mdrums

Lindsey, I wish I was at Sebring Sept 7-8th but I am out of town on business on the 7th and probably will not have my new wheels and tires by then. My stock tires are now corded and hopefully I will have a complete new set end of this week or next. The go cart deal looks like fun and something I could really afford! HA HA!

NJcroc, thanks, so the Carrera III are for the wide body Carrera 4 car? The think that keep confusing me is that my stock wheels are 11.5" wide with a 67mm offset but the Carrera III wheels are only 11" wide and I have been told that effect the offset but I do not know the math used to figure all this out. I believe 6mm is around 1/2 and inch, correct? So would 11.5x19 wheels with a 67mm offset be around the same as a 11x18 with 60mm offset?

Also some people told me today that 315/30/18 will fit and some say they will not fit and I need 295/30/18's since Michelin Sport Cups do not come in a 305/30 size. Correct?

mdrums

TTT..anyone? I know there are some very smart guys here with a ton of knowledge on this subject that can lead me to the correct choice.

Thanks, Mike

LVDell

Mike, I don't think you have near enough camber for the cups to work effectively. That would be a waste of money IMHO. Personally, if I couldn't get any more camber out of the car I would run PS2's or RA-1's depending on size availability. I ran PS2's on my GT3 for some time before I moved to R-comps and they were fantastic on the track and really "talked" in a way that I was able to really learn the car AND STILL GO FAST! Can the cups be run with your camber settings? Of course. Optimal? Not even close.

RonCT

Stick with the Volks as they are the correct widths and offsets for what you want (8.5" and 11" respectively) vs. oem at 8" and 10" (correct offset) or 8" and 11" (incorrect widebody offsets). The only tires for you are 235/295 PSC based on what you wrote. If you go with RA1s (what I'm driving now, but will go back to PSC next time) sizes are 245/305.

Gary R.

Are "Volks" a good quality wheel? Everything I have gotten for tire rack has bent (2 sets of winter wheels for my BMW), never looked at the brand. Why not take a look at CCW, for approx the same cost you will get a forged wheel with custom offsets for your car.

RonCT

Volks are made by Rays wheels -- perhaps some of the best wheels out there. Very strong, very light, warranty, etc. Only have heard great things about them. I thought turn-around was key -- he wants the wheels and tires ASAP. Last I asked, the wait time for CCW was pretty long.

Gary R.

Thanks for the info Ron, was just my ignorance of the branding... I hope CCW's wait for reconditioning isn't as long, just sent two wheels to them!

racewheel

turn-a-round is 2 weeks or less on the ccw's
john

Gary R.

Thanks John, hopefully you can find out what's up with the two I rebuilt, (my guess is the center section got whacked out) they went out UPS ground yesterday.

mdrums

1 thing is am concerned about with the Michelin Sport Cups is the rolling diameter comapred to stock.

stock is..............25.5 front
.........................26.3 rear
MPSC 235/40/18 is 25.4 front
MPSC 315/30/18 is 25.5" rear


I did look at CCW and I like them but turn around time is to long and price is getting out of my budget. I looked at BBS and Fikes too and they were way to expensive for what I need.

mdrums

Dell, yes I saw the camber "recomendations" and that has concerned me. Toyo RA1 and R888 camber recomendations are the same as the Cups. So I'm screwed either way. Problem is PS2's are more expensive than Cups or RA1's in the 18" sizes $293 fronts $416 rears EACH

NJcroc

the carrea III wheel comes in 2 sizes. a 10x18 58 offset standard on the carrear and a 11x 18 51 offset standard on the carrera 4. if using a 18 or a 19 inch wheel the offset is the same and should be a 67 offset. your standard 19 inch wheel is the largest available and sits 1/2 inch closer to fenderwell as it has the correct offset