Originally Posted by
jeirvine
I assume on these you can't just swap out the freehub with a more compatible model? I've swapped 8 to 7 sp and vice versa many times on old 105 and 600 hubs.
The Dura-Ace 7800 freewheel unit is incompatible with earlier versions in terms of mounting. It is not entirely self contained like earlier units. The freewheel unit contains only the pawls, with the ratchet teeth being part of the hub shell.