Kdx Kx hybrid,,,, rim question

ok

im currently building a hybride enduro bike

a 1999 kx125 with a 1990 kdx200 engine.

my question concerns the rear rim.

i want to fit an 18inch rear wheel and i can get a good deal on a set of excel rims

front 21x1.60

rear 18 x 2.15

is the rear rim going to be ok? i know its a little wider then standard?


any advice would be good

thanks

Mark