Originally Posted by
Hinge
Exactly which Sram hub do you have? I'd like to check it out.
I am using the
SRAM Dual Drive hub (v.2) which, in addition to taking a regular cogset, provides for three drive bands. Over-drive at 1.36x, Drive at 1x, and Under-drive at 0.73x. You can think of it as a multiplier on your chainring, or a multiplier on your effective wheelsize.
The advantages? Wide gear range, plus the three advantages I listed in the earlier post. Another advantage is that the hub, clickbox and needle (the interface between the hub innards and clickbox) costs
only $150.
The disadvantages? As I see them, and for my use and experience in two years, there is only one minor disadvantage, the weight. The hub alone weighs 960grams, which is about 2.5x the weight of a normal freehub. Others will say the
allegedly fragile clickbox is a disadvantage. In two years of riding, and riding hard at times, the clickbox has never come off once, and it is intact with no damage at all. The clickbox, imo, is a non-issue. Still worried? Carry a spare. It costs a whole $10, weighs 90 grams, and is easily available at Amazon. Ditto for the needle; five grams, five bucks. In the event, catastrophic failure of the clickbox still leaves you with the entire range of the cogset in Under-drive (18-59GI) at your disposal. It does not mean you will be walking back.
Another disadvantage is that v.3 of the hub comes only in 36H, and that is overkill for 20" wheels. Good thing I have the v.2 hub with 28H. Finally some will say that there is some drag or loss of efficiency in Over-drive. I haven't noticed it. Perhaps because my hub is still in tip-top working condition.
You want the top range of a 55T ring on a 622 wheel? Easy peasy. 57T ring with the SDD hub on Over-drive. Worth the price of admission for people's reaction as this seemingly docile pony hauls @zz.
What does it look like on the bike? It looks like a regular derailleur drivetrain, plus the clickbox.
18-108GI on tap!
