Originally Posted by One Less Harley
are all upside down forks from KTM 250 and up all 4860's?? What about spring rates, caliper mounts and axles? I assume they are different? Would it be better for the front end to come from a 250cc or larger and 2000 and newer? I haven't seen where this has been discussed w/ the 4860's. Just thinking of picking up a set for possible future use.
What's written below is MY UNDERSTANDING
and should not be taken as fact. Do your own research. That said:
They started using 4860s in 2001(?) I believe and not on all models, some got the 4357s. In 2003 they did away with the 4357s and changed the axle size on the 4860s from 20mm to 26mm. In 2007 they switched from what they call a single chamber design to a dual chamber (what the rest of the world calls cartridge forks). I can't remember which models from 2007 on got the closed damping cartridge (only SX models?). As far as I know all the 2003+ 4860s use the same 26mm axle except for the 950/990 adventures which use a 30mm axle. From everything I've read all the 4860s have the same caliper mounting arrangement. Steer clear of the supermoto models as they appear to be unique in a lot of ways and are incompatible with a lot of parts that all the other models share. Also, the 950/990 adventure models have longer uppers and shorter travel than the dirt bike models. The 640 adventure had forks that as far as I can tell are identical to the dirt models with the exception of optional dual discs.
In short, the 125-525 SX, XC, EXC, models 2003-2011 are identical externally (length, travel, caliper mounts, axle). The SX models (I think) from 2007 on have closed cartridge internals.