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How well do dinglespeed set-ups work? Particularly with respect to a ss cyclocross bike where you'd be running 2 40-somethings up front.
Can you get the double cog at the back on a freewheel, or is it something you'd need to run fixed?
Is there much spread between the two gears you can run, or is there really not a great deal in it? The surly website is talking about a diff of 2 teeth either end. I can see a bike with horizontal drop-outs working ok to take up any potential slack in the chain when you changed over.
Finally, does it actually work reliably or is it a PITA with chain lines, only working for a few select ratios etc?
i did it for a while can't remember the exact ratios but it was something like 32/17 and 38/13 so 1 cog from being equal but the difference in chain wrap made that of little consequence. this was with a dialled ebb love/hate so switching was hassle free, i used mine in a commuting weekday and off-road weekend guise.
hub was a profile 6-speed cassette hub so room for 2 cogs and good chainline, the surly wide based cogs gave you perfect spacing (single cogs not the double ones)
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genesis io
inner set is 32/18 outer 34/16, the 11t cog is for the lockring for the freehub.
32 is in middle ring posn, 34 in big. no reason why you could not fit different ratios.
Thanks. I have a pompino in mind so with the track spacing I was wondering if there was space for the double cog - I see that you can get double freewheels and they look similar in size to a single. Pricey though.
white industries do one i think. can you not use a freehub wheel instead, and a couple of the sulry rear cogs, as i did?
Don't think so - the frame is too narrow (120 mm spaced) to take a freehub wheel. The double cog freewheel thing does look like it would work though.