Sorry, you can't keep up with the roadies on the downhills because of the gearing on your bike is too low?
There's only so big a chainring you can install on a 406er before the ring is too big for the chainstay, it leaves you with gearing too tall for the hills, or it just looks incongrously big.
An great option for wide-range gearing on a small-wheel bike is the SRAM Dual Drive hub. I've got one with a 47T single ring which, coupled with the SDD hub, is as if I were carrying a 64/47/34T triple crankset. 64/11 gives about 108GI. Couple it with a 53T and an 11-36T cogset, and you've got a 72/53/39T triple with 20-121GI. Another advantage of the SRDD is little cross-chaining on the single-ring drivetrain; instantaneous, no-clunk shifts; and ability to shift at a standstill.
Originally Posted by
Hinge
I think your gearing is larger than the X20. As far as I know, the X20's largest gear is 55/11.
I have a heavily modified P18 (w/ 20 speeds)
I do a fair amount of riding with fairly decent riders on full size CF bikes w/ 700c wheels. On flats and hills I'm right there with them and often ahead of them on hills. However, on descents, I don't have a chance. It's simply impossible to keep up. They lose me every time.
I agree that it largely comes down to gearing. My largest chainring is 56 and smallest cog is 11.