How much give is there in tire sizing? I have 80/100 and 110/100 tires on the WR400. I have no idea what was stock. These particular sizes appear to be somewhat uncommon. Yes, I know I can change the 2nd number a bit and aside from ride height and the bike tilting fore/aft a little bit, it's no big deal. But what about width? 90 width up front and 120/130 out in the rear seems to be more common. dirt bike rims seem preciously narrow. do the wider tires still use the same bead width?