12" motard rim issue

[twiztid]

I have a 125cc with 14" front and 12" rear and wanted to put a 12" rim on the front, but I was told a 12" won't go on, I would have to change the front end.
Any info on this would be great.

 

[my67xr]

why won't it go on ?
it should be the same if you find one with the same sized disc and same size axle
it will drop the front end height a bit though with a 12" front

 

[twiztid]

That's what I thought but been told otherwise.