19"front with 18" rear?
I have a complete spare 18x2.5 rear wheel/rotor/cush hub/sprocket for my 690 enduro and I have been using it to swap back and forth from trials tire to knobby. I find that I never use the knobby anymore so I could put a 90% onroad type tire (pirelli MT90?) on my spare rear wheel and use it for my short daily commutes and running around. That being said, I've been keeping an eye out for a complete front wheel to put a street tire on and came across a bare front hub. I was originally just going to run street tires on 21/18 wheels but being that I'd have to buy a rim and spokes for the front anyway, is there any onroad benefit to running a 19" front if I still have an 18" rear? Should I just stick to my original plan and lace it up 21"?