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I've been on Sheldon Brown site and although I ended up with some number comparrisons, I'm not really sure what I'm lookig at or what the real world implicatiuons are.
Currently ride a 26" bike with a 24T x 36T granny
How would a 29" bike with a 32T x 42T (X01) granny compare
Much harder? How would it stack up if it was changed to 30T x 42T granny
Finally, can a Hope retainer (narrow wide thing) be used instead of the X-Sync SRAM chainrings on an X01 chainset without messing up chainline or clearance issues?
Thanks
26*24/36 = 17.33
29*32/42 = 22.10
29*30/42 = 20.71
So a 30/42 combo on a 29er would be approx 20% harder than your current setup. 32/42 would be 28% harder. Quite a bit harder either way.
A 29er wheel is roughly 10% bigger than a 26er wheel for the same profile tyre. In ratios:
24/36 = 0.6667
32/42 = 0.761, multiplied by 1.1 = 0.838, which is about 25% higher than your 26er, or 2 gears off the bottom
30/42 = 0.714, multiplied by 1.1 = 0.786 (18%, one gear less at the bottom end).
Andy
The missus did the same, started with 34t X01 and dropped it to 23t for more all round riding.
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This was a good table for a quick comparison, the feel was 34/42 was low, 32/42 was really low! She has been going well on it and is happy on the real hilly stuff. The proviso would be it depends on your pedalling style and the hills round your way.
Ah, this is very helpful, pretty sure I understand now...best head out to buy a 30T ring 🙂