Old 07-29-20, 04:40 AM
  #49  
BromptonINrio
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Join Date: Apr 2017
Location: Rio de Janeiro
Posts: 377

Bikes: Dahon Curve Sturmey Archer Srf8; Brompton Sturmey Archer Srf8; Brompton M6r

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Originally Posted by tomtomtom123
Is the Rd total chain wrap capacity 41t? You could exceed it as long as you make the chain long enough to get to big-big, and allow the small-small to drag. This means you won't be using the outermost small-small combinations. You can calculate how many gears will drag by comparing the chain wrap capacity to the real wrap. It's ok not to use the outmost combinations since they overlap with some of the big-big.

I have 12-34t 10 speed cassette with 24/44t chainrings. It gives me 519% range with 14-72.6 gear inches on 406x2.1 tires. I mixed my cassette to get 12,13,14,15,17,19,21,24,28,34. This gives me preferred closer stepping at the top and much wider at the bottom. The 20t jump at the front is fine as long as I use a chain catcher. SRAM yaw FD comes with one. The yaw design also makes it so that trim is not necessary but you may need to widen the cage, I had a thread explaining how to do this.
Wow!
this gearing is very low!
you probably spin out on flats and spin ou on any incline!
if you find a hill for that low speeds you would probably best pushing the bike, it eill be faster!
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