Tires:how wide is too wide

[jcbikeboy]

I checked the FAQ for all the suitable tire sizes, But I was wondering if anyone is running 215/40 17's in the rear?? Also, I was wondering is 215's up front might slow the steering response a little, and is so would 205 up front and 215's in the rear be suitable,or dumb?? Any advice,opinions etc appreciated!
Also I'm looking at some 17" ADR rs limited s type wheels and was wondering if anyone has had any experience with them??

[Red & White Cooper 2]

The FAQ only seems to consider tyre diameter. While I have no experience of fitting or running non-standard sizes, I would quote from Robin Ford, the engineer responsible for the front axle.

"We had to re-write the rule book on tyre and component clearances. In fact we threw the rule book away. There's meant to be a 15mm clearance for tyres. Now there's actually a benign foul in extreem circumstances. The 17 inch wheels on the Cooper S were an absolute nightmare to accomodate."

I may be wrong, but from the above I'd think twice before fitting non standard size tyres to the 17" wheels on the Mini.