bgiere

Can I run 225/40 18 fronts and 245/40 18 rears on a 964? I am tire size illiterate.....

CWay27

Why 245 at the rear?? A 245 in 18 is pretty much a 225 - 235 in 17". Go with 265 and that fits perfectly on a 9" wheel.

sleder

I have een using 275 x35x18 hoosiers rear and the 225x40x18 front. Who makes a 265?

MarkD

Kumho, Yokohama, etc...

See tirerack.com for more...

Bill Verburg

You could but why would you?

assuming you have at least 8" & 9" wheels 225/45 & 255/40 or 225/40 & 265/35 or 235/40 & 265/35 or 235/40 & 275/35 are some of the usual combos, not all brands are available in all sizes.

The f/r tire sizes can be juggled to enhance or eliminate handling characteristics that you want or don't want.

The rear tire size has a direct influence on gearing

So you need to consider what sizes are available in the brand you want, then the f/r differential of sizes and gearing consequenses

CWay27

My tougth exactly...... Couldn't of said it better

To sleder;

265 is (in my book) the most comon size for 18" wheels. Tire height varies alot but 265 came stock on alot of P-cars..... 996, cayman S......

bgiere

well....here's the situation...I have a brand new pair of Hoosier 245/40 18's...tried to get them on the front and they rub just a tad too much...hate to throw them out so I was going to use them for practice/DE in combo with a 225/40 18 front....

Bill Verburg

Maybe sell them?

Where is the rub?

Gary R.

I run 235's and 265's Michelin Pilot Sport 2's on 8" and 9.5" Fikse 18's and they just fit.

bgiere

Bill, rub is on the fenderwalls on both sides at full lock turn...I have had them adverstised in Pano and Rennlist classifieds for 2 months so I figured noone wants 'em....

2Brak

Brant, these guys are right in that 225/40/18 and 265/35/18 is the most common combination but there are others that are closer to your stock diameter. Your tire choices will be less though. Let's looks at the choices.
Stock diameters front to back is 24.9"

The closest size 18's to stock is 215/40/18 - 24.8" and 245/35/18 - 24.8".
Absolutely no rubbing isues what so ever. so using 245's is a valid question. Someone asks why, the answer is it is closer to stock than a 265.

Another combo is 225/40/18 - 25.1" and 255/35/18 - 25.0".

225/40/18 and 265/35/18 is the most common but the diameters are 25.1" and 25.3"
265's are 1.8% larger diameter. So yes they'll fit but they aren't the closest size to your stock.

Bill Verburg

If it's like mine(look just to the right of the rotor), I wouldn't worry about it. If you want you can attach some ss rub strips to the chassis.

964 Cup cars used 245/620x17 & 265/630x17 on 8 & 9.5 wheels, rains were 235/17 & 255/17

It' very difficult to come up w/a modern equivalent in 18" sizes from a single manufacturer.

Ideally the 245/40 x18 would want a 265/35 or 275/35 x18 rear but it depends on the manufacturer. Hoosier for instance doesn't have the R6 in 265 so you would go to 275 which presents it's own issues wrt width. It can be done many use the 245 & 275 combo but you gave to have the right wheel widths and o/s.

generally for a track only car, which I am assuming your Cup is, the wider tire is the more desireable(up to a point of course)

Larry Herman

I am running 245/35 18s on 9" wheels and 285/30 18s on 10" wheels. Everything rubs a little on the inside and is very close on the outside, and I have to run steering stops on the front to keep from ripping off the brake ducts in the pits. Such is the price of grip.

PWW

Ok so if putting 8 x 18's and 10 x 18's on a C4 what would the ideal tyre size combo be based on avaiable tyres?

CWay27

Besides getting in and out of the pits, I don't think you'll ever have to full lock on a circuit. Depending on your offset, you could use a 3 to 5 mm spacer just to ease your mind.

To PWW;

best fit and most accessible with tire brands are
225/40/18 front and 265/35/18 rear.