Tyres on turbo cups

[neon_fox]

Quick question for you guys, I have a set of 17" turbo cups on my 964C2, and I would expect those o be 7J and 9J fornt and back respectively.

When I bought the car it has 205/50 on the front and 255/40 on the back.

When I look at a tyre chart it says that 205/50 is a 6.5J tyre, not a 7J, does this mean that turbo cups are a 6.5J front (I thought that they were 7J) or that I should be using a 215/45 or a 225/45 on the front...

Answers from someone more rubbered up than me appreciated.

Fox
---

[ian964]

The original factory Cup 1 optional wheels on a 964 were 7Jx17 with 205/50 front and 8Jx17 with 255/40 rear - seems a bit odd, but that's what the factory supplied. Most people now fit 9J rears, but with the same rubber.

So you probably do have 7J fronts. I've heard of some people fitting 225/45, but you may get some rubbing - have a look on Rennlist, there's always loads of tyre threads there.

cheers
Ian

[ian964]

Oh I forgot, if they're genuine Porsche wheels, they'll have the rim width and offset embossed either side of the valve stem. Should be something like 7 and 55 for a cup front.

cheers,
Ian

[oldtimer]

your tyre sizes are fine. for reference, the 964RS cars were fitted with 17 inch x7.5J front wheels and 205/50 ZR17 tyres ( tyre width about 8 in), and 17 inch X9J rear wheels and 255/40 ZR17 tyres ( tyre width about 10 in).