Race Tire Fitment

[dr.evil]

I have an 04 S4 Avant that I am hopefully going to be able to get some track time in the week. Customers are renting the Moroso for a few days next week to do some shakedowns/testing on the FR500S's we are running for them in the Miller Cup/Mustang Challenge. Hopefully they won't mind if I take my Audi out for a while after they are done for the day. Anyway the tires on the Mustangs are 245/40ZR18 BFG G-Force R1 DOT full race tires. We usually run a set on the mustangs for about a total of an hour track time before putting on a new set. Now these tires still have plenty of life left in them, its just not a new tires and the customers want new tires for every race. So that leaves me with a nice supply (we are running 4 cars in this series) of these tires. I'm just wondering if they will fit on my stock suspension S4 with the factory 18" wheels. The factory size is 235/40-18, just wondering if that extra width will pose a problem for me. I have all the tools at the shop to swap them over to my wheels, just dont want to go through the trouble if they won't fit.

Thoughts/experiences would be great.

[B18b1ex]

Stock tire

Sidewall 3.7
Diameter 25.4

245's

Sidewall 3.9
Diameter 25.7


And with the 10mm extra width about 5mm on each side I think it should fit. If not you could always run a 5mm spacer.

If you can get another set I'd love to have some to try on an autocross. That is if they are just throwing these away I'll come pick up.

[dr.evil]

went to swap these tires onto the stock wheels today. Had problems getting them mounted, possibly because of the extra width...? I'm not a professional tire jockey so that might be the problem too, but I usually have no issues mounting/balancing tires. I've read some threads of people running 255's on the stock wheel, so Im sure the 245's will fit. Just need to figure out how to persuade them to mount onto the rim.

[91gl]

You shouldn't have a problem mounting tires with larger width's onto your stockers since I know quite a few people who have don't this. My guess is that since they are race tire that they have much stiffer sidewalls for the extreme cornering they face during a race and need alittle more persuasion to get on.

[Cargo8]

could be the offset. may need spacers to bring it out towards the fender away from internals.