Originally Posted by
Sammyboy
Actually, 20's came with 451's to begin with. Sounds like a cool project, I've not seen many derailleur geared 20 upgrades.
R20s in North America came with 406mm, in the UK they came with 451's... A lot of the R20 projects I've seen use geared hubs, and at first was considering a geared hub, BUT, in order to keep costs lower (decent geared hubs can cost a lot), I decided on a derailleur system with the added benefit that if it breaks down, I can fix it/replace it easily anywhere I am.