will a stock 250r axle fit my 300ex? Is it wider than a stock 300ex axle?

 

I don't think an R axle will fit in a 300EX carier. It should be wider than the 300's.
ERIC

 

Yes it's wider, no it won't work....

Two reasons:

1.) Different splines - no big deal, just use 250R hubs, sprocket and possiby brake assy....

2.) The 250R is wider at the axle carrier - you'd have to change swingarms, opening a whole new can of worms....