Depends on the route.
I went up over Mullach Nan Coirean over Stob Ban and back into Glen Nevis at the bridge.
This is a waste of time. Huge carry up, the top section of SB is too rocky to ride and the bit I thought would be awesome from the bealach to Glen Nevis is really disappointing. This is mainly because the path runs through such a deep and narrow rut that it is impossible to fit your bike through parts of it.
Mind you, I had fallen off and hurt my arm to the extent that I was basically riding one handed so perhaps it isn’t quite as bad as I remember.
Other routes are available.