my mom has 1.25 on her '02 sxr and they are great no rubbing at all!!!

It all depends on your clearance at your smallest clearance point, that being at the front heat exchanger mounted to the front bulkhead. To run a larger lug track, you would need to reduce the size of the sprocket, like going from an 8 tooth driver to a 7 tooth to provide more clearance from the top of the lug to the heat exchanger.

Also, if you plan to stud a track with more lug height than 1.5", your stud options are very limited as the only ones you could use are snowcross studs.