Old 01-14-17, 10:49 PM
rm -rf
don't try this at home.
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Originally Posted by DougG View Post
Since I doubt that I'll be able to get the 46/30 crank that I was hoping for, I'm thinking now that instead I'll swap the OEM Shimano 11-32 (11-speed) cassette for an IRD 12-34. With my 48/32 crank, that gives me close to an identical granny ratio (32x34 instead of 30x32), and I don't think I'd ever be on that 11-tooth cog either.

The cogs I'll use most would have a 2-tooth spacing (13-15-17-19-21-23-25-27), making it easy to find the right gear for any occasion. I've found that a spacing of three teeth is often a case of one feeling a bit to high and the other just a bit too low; two is just about right.
That's a nice low gear. But I don't like the IRD cog spacing choices. Their 21-23-25-27-30 is a lot closer together than their 12-13-15-17-19, so there's fairly big shifts past 15 mph.

See this setup in Mike Sherman's gear calculator, and a chart attached below.

Compare to a (non-existent) custom 12-13-14-15-16-18-20-23-26-30-34 here. (But they don't make a 26 cog, or even a 16 cog!)

I thought the IRD 12-32 might be good for me, but I don't see much advantage over the Sram 11-32.

11-12-13-14-15-17-19-22-25-28-32 Sram 11 speed
12-13-14-15-17-19-21-23-25-28-32 IRD 11 speed, this adds the 21 (and 23 vs 22) instead of the 11.

Attached: 32/48 and 12-34
Attached Images
File Type: jpg
ird12-34.JPG (89.3 KB, 507 views)

Last edited by rm -rf; 01-14-17 at 11:10 PM.
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