Brake disc Width

what will happen if i use disc with a width which is outside the range of caliper specification?like in wilwood caliper they have specified that it can be used for disc width ranges between .15" to .20".But i want to use it for disc with .10" width.

There is apparently something lost in translation here. I don't think you could possibly be talking about .10 inch width of a disc brake caliper.

-Rod

possibly 15mm 20mm or 10mm?

Best to follow the specs. 15 to 20 would be fine. A minimum of 15 won't hurt either.