Originally Posted by naginalf
Does 4860 mean 48mm top diameter, 60mm bottom? Just wondering because I'm considering getting a set of HPMguy triples, and it looks like he's doing a run of both 50s and 4860s. I prefer the 50s and have a line on some
, however the 4860s are much more common and modern. So my crazy brain is thinking, why not get a 4860 bottom clamp and a 50 top clamp, machine up a 5mm aluminum collar for the 50s to fit the bottom clamp, and if I ever get a set of 4860s, I can simply use a 1mm shim on the top clamp. Feel free to tell me I'm a crazy idiot , but at least assuage my ignorance in the matter .
That's not how it works.
You need to differentiate between upside down and conventional forks:
50mm Extremes are conventional, so both upper and lower triple clamps clamp to the 50mm slider/stanchion (the chrome part on top).
The 4860 are USDs that use a 48mm slider (the chrome part on the bottom). Their upper tube/stanchion measures 60mm where the bottom triple clamp clamps to and 54mm on top.
Clear as mud?