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handfab
09-04-2009, 10:34 AM
Hello all,
I switching over an old mountain bike to a single speed street communter set-up. The online recommendations I've read for off-road riding is a 2:1 chainring to cog ratio ( ex. 38t chainring and a 16t rear cog). Does anyone ride anything different? My commute is only about 6 miles from NE to downtown, relatively flat.

appreciate any input.

bubbaPDX
09-09-2009, 04:20 PM
I followed Sheldon's advice (http://www.sheldonbrown.com/singlespeed.html) with excellent results:

"Generally, for street use, with a freewheel, I would recommend a gain ratio of around 5-5.3, for instance, a 42 tooth chainring with a 16 or 17 tooth sprocket.
You'll see other sites recommending '2:1' gearing, which typically gives a gain ratio of about 3.7. That's good if you are going to be riding off road on steep mountain trails, but a gear that low is maddening on the flats and particularly on pavement, because your speed will be limited by the tendency to 'spin out.'"

You can plug your chainring and sprocket data into Sheldon's online gear calculator (http://www.sheldonbrown.com/gears/) and see what kind of gain ratios you can come up with. I've been commuting with an approx. 5.4 gain ratio setup, which serves me well (in street clothes, with a couple of moderate hills). Good luck!