Originally Posted by
Sheldon Brown
OK, so low gear is 100%, high gear is 350%.
350% - 100% = 250%. That's the _range_.
See also
http://sheldonbrown.com/gears/internal
I just got one on my Greenspeed trike, but I've only had opportunity to ride it for a couple of miles so far. So far, I like it a LOT!
Sheldon "Digital Isn't Always Best" Brown
Hi Sheldon - I think the hub itself has a range of 350%. If you include the sprockets in the equation it changes everything. For instance a 34 ring with a 17 freewheel: then in low you get .5 (hub) x 2 (sprockets) = 1 (one rev of the crank = 1 rev of the wheel, or 100%) and in high 1.75 (hub) x 2 (sprockets) = 3.5 (one rev of the crank = 3.5 revs of the wheel, or 350%). That is a total effective range of 350% - 100% = 250%.
Now lets say you choose a go-fast ring with 52 teeth and the same 17 tooth freewheel. In low you get .5 (hub) x 3 (ish, sprockets) = 1.5 (one rev of the crank = 1.5 revs of the wheel, or 150%) and in high 1.75 (hub) x 3 (ish, sprockets) = 5.25 (one rev of the crank = 5.25 revs of the wheel, or 525%). That's a total effective range of 525% - 150% = 375%.