Tyre Sizes;Max size in a rocky mountain fusion 1995

[rocky mountain]

hi,
how reliable are tyre sizes against reality

i want to put some 2.35- 2.5 tyres into my frame, the rear is the problem, i have pace carbon forks up front.

any thoughts/help,

simon

 

[gump]

hmmm not go above an average 2.1 in the back of my old rockies..