I have the same prob... I am running 31's on my tacoma and my spare is a STOCK 225... should I get a 31" for my spare?

I have 4 31 BFG Muds sitting around I could give you one for a spare for free. But shipping would be killer. Well let see here on the approx (APPROX) height chart:

215=27"
225=28"
235=29"
30x9.5
31x10.5

I have used a 225 spare with 215's and 235's no problem. But using a 225 with 31"s is the same principal as using a 31" with 33"s. Maybe she is willing to part with her old 31" spare for a good price? Something you might want to ask. But yeah not a good idea to try to run a 225 with 31's. At very least go for a 30x9.5. <img src="/forums/images/graemlins/kewl.gif" alt="" />

then i guess a bald 35" tire for a spare wont be good if i have to run it with my 38's <img src="/forums/images/graemlins/notooth.gif" alt="" />

I wheeled alot with an undersized spare. But, it is definately out of the question with any new traction control system, as the binding just multiplys.

Also depends on the wheeling. For the long, Sierra Challenge you are planning to attend a full size spare makes far more sense due to likely hood of tire failure.

Also, if you wheel the Sierras alot, buy that free replacement warranty as it will pay dividends!