ckkrause

I've been searching in vain for info on the best tire size for a C2. I have 7 & 8 x 16 Design 90 wheels, (I don't care, I like them!!!), and I do autocross, some driver's ed & SCCA HP @ Thunderhill, as well as some commuting in the car. I currently have the original 205/55 & 225/50 on it. I am planning on going to 225/50 & 245/45 tires for more grip and the 225 for reducing understeer. What are some of the +/- 's of going to the wider set of tires. Will they accomplish my goals? Thanks for your reply!!!

-CKKrause

Adrian

You mean 6X16 on the front. This makes a huge difference because you can put a 225 on a 7X16 but not on a 6X16.
The 245 is fine for the rear.
I would advise with a C2 to try 205/245. 225/245 I know work really well on 16 inch wheels for a C4 to reduce the understeer. I know this combination has worked well on a the Carrera 3.2 and 911SC but I do no know about the 964 C2.
However as I said I would check those fronts to see if they are really 7 or 6 inch wheels. Standard was 6 inches.
Ciao,
Adrian
964C4

ckkrause

Adrian-

The fronts are off a 944 S2 (?) and are indeed 7 x 16's. So, with that in mind, I hear that your saying for understeer, (yes, the C2 have quite a lot as well!) 225/50's are a good thing? Also, I guess it goes without saying that grip is increased? Thanks for your response!

-CKKrause

Adrian

The 944 version of the D90s is slightly different in internal dimensions but this will not be a problem.
Grip increased depends entirely on the tyres you purchase. If you purchase tyres which have at least been tested and proven on a 964 then you should get more grip. If you purchase unproven tyres then you could end up with some troubles.
Ciao,
Adrian
964C4

ckkrause

Sorry, I didn't finish my thought above. I assume grip will be increased over the original size wheels/tires, given that the same tires are used, just in the larger sizes...

-CKKrause

Adrian

Yes that is basically correct. My comment was a general one because this tyre issue is one that whilst it seems simple gets complicated because people are budget conscious especially when purchasing tyres.
964 ownership requires a more open wallet policy. Cost of ownership of a fine sports car is something that people have to understand is not cheap. Hence my comments.
Ciao,
Adrian
964C4

jimq

Will the 245/45 tire on the rear of a C2 cause any rubbing issues or is a offset spacer also needed to clear oil lines and such? my car sits at the US stock height. Also will this tire circumferance be comparable to the 225/50 so as not to throw off the speedometer to much? I guess as I have the stock D90's I will need to keep 205's on the front. anybody tried this set up and your thoughts?
Thanks

MelissaM

Jimq,

I had the 245/45 on the rear and 205/55 on the front of my D90's (before I went to 17's.)

The 245's didn't rub in the back, and I didn't have any spacers back there. With the 205's I didn't notice the understeer, but I was driving on the street and wasn't pushing the envelope enough to notice understeer.

-- Melissa

ckkrause

Jim-

My research showed that the 245/45, 225/50, and 205/55 tires all have a circumference within 3% of each other. No problem for me...

-CKKrause

BaysideC4

I just called tirerack (I am in the market for new tires too). I am looking at the Kumho VictoRacer. He said the 245 45 on the rear is no problem and the 225 50 in the front will fit (they are rated for 6-7.5 rims). The only problem could be that the tires may be too wide for the front fenders. But they will fit and are recommended by Kumho for 6” rims.

Is anyone using 225 50 16 in the front with a stock suspension?

Adrian

I would never put 225s on a 6 inch wide rim. Yes they will fit easily inside the wheel arch at standard ride height on standard suspension. I would just not recommend it. The tyres will bulge. It is funny how different tyre companies act and what they say. However it is your money.
Ciao,
Adrian
964C4

BGLeduc

Yes. That is my track set-up (225/245 Victoracers).

In fact, I have now lowered the car with H&R springs, and it still works fine. I do get a very small amount of rub on the inner wheel well at full lock, but thats it.

I would agree with Adrian in terms of the tire bulging, but a 225 on a 6" rim is a very common set-up in autocross circles. I also ran them on my Integra Type R when I had it.

Are you saying you plan to run Victoracers on the street?

FWIW, they are a very streetable race tire (although I would stay away from standing water). In fact, my C2 with Victoracers on Design 90's rides better on the road than my street set up (Cup 1 replicas with Kumho 712's).

BGL

BaysideC4

Thanks BGL.
They will be used for Autocross and DE events only. Well, maybe getting to those event too.