Tire sizes

[625SXC]

I am gonna be getting some new tires for my wifes Dt175. Original sizes are 3.50-18 & 2.75-21. I am looking at different tires. What sizes compare with the 3.50 & 2.75 sizes? I have a brand new Dunlop D606 front that I will never use on any of my other bikes and was thinking about getting D606 for the rear. I just don't know if the D606's will be too big for the lil' Yammi.

90/90-21 & 120/90-18

[phillybeef]

The 606 is too big and heavy for a 175. It will make the bike feel sluggish and the rear will unnecessarly load the whole drive train. I'd use tires sized for a 125, try a 100x100x18 rear and a 80x100 front.