Biggles

Purchased my 2004 XR6T 3mths ago & driven less than 2,000 kms since then. It has only 51,000 k's on it now. RH front caliper has a definite rattle to it when driving over bumps & mechanic blames it on the 19" rims & 35 profile tyres. LH caliper is fine. This rim/tyre combo was brand spankers @ time of purchase. I know this combination will be rougher but would that be the cause of what appears to be slide problems or is it just BS from the mechanic. Has any1 else encountered similar issues?

Picked up my first XR6T about a month ago (2004 model, no mods, stock standard). Owners handbook recommends 95RON minimum. Chatting to another XR6T owner last weekend & he reckons his runs AOK on 91RON. Whats the general consensus on this?