Supagoat

Why would anyone want to do that?

I'm considering going to race tires for autocross next year, and one of the local active autocrossers races his GT3 RS and is willing to sell his cast-offs cheap (with enough tread for maybe 8 days - 4 since I'd be dual driving)

His are on 18s, and the fronts are 255 which is no problem, but the rears are of course 315s. I don't even know what that would do to the balance of the Spyder. It might be terrible. But first I figured it'd be good to find out if it's even possible.

Marine Blue

More weight which could throw off the cars balance and overall stability. Then again it's much more tire too.

I would be curious to get your impressions if you follow through.

orthojoe

I don't think it's possible, nor would you want to. Bigger is not always better. You'll induce understeer and add a lot of weight. I'll bet you would be slower

mooty

it will not fit
and if it did fit with 255 front, your car will push way too much for auto cross
for AX i would run 255/275 if you are really good with fast hands. else 245/275 would do.

2XIPA

Yes, That. ^

BGB Motorsports

We sell our 245/275 18" Continental Take-Offs for $50 each. They're good for 1-2 weekends minimum as they were retired by "pro" drivers that needed stickers every other session to feel good.