you dont happen to know about the axles on a 99' 750 do you?
If you mean 99 Monster, then it will have the smaller axle size(s) you're looking for. If you mean 99 SS then I think that's the year the SS's switched to the larger 25mm front axle.
(Either way the rear will fit, just make sure you get the conical spacer and cush assembly just to be safe)Monster wheel sizes
1993-1999 20mm front | 17mm rear
2000-2001 25mm front | 17mm rear
2002-current 25mm front | 25mm rear (for dual sized swingarms)
SS wheel sizes
1992-1998 20mm front | 17mm rear
1999-2002 25mm front | 17mm rear
(I think that all the SS's from beginning to current use(d) the 17mm rear, but I'm not 100% sure)The below is for either/both SS and Monsters
All front wheels are 3.5" inches
All rear wheels for any SS or Monster
except 900's are 4.5" inches
"Most" rear wheels for 900's are 5.5" inches, but sometimes got stuck with 4.5's <-- most are 5.5's
and yes, you can swap in a larger (5.5") wheel, just make sure you get the conical spacer and cush drive assembly too as they're different widths between the larger 5.5" and smaller 4.5" wheels. And if you have to ask about bearing size differences, then just get the right size and be done with it.
