Singlespeed & Fixed Gear - Chainring problem
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10-11-10, 11:15 PM
10-11-10, 11:31 PM
I'll pretend I know what's happening.
10-11-10, 11:54 PM
I feel like I'm stuck in a digital game of Snaps...
Snaps is the name of the game. The name of the game is snaps. For crying out loud, take a guess. *five snaps* C'mon, you got it, right? Kidding around won't help you get this one.
10-12-10, 07:43 AM
Unfortunately what you're experiencing is one of the common pitfalls of converting a geared road bike frame to single speed. Because of the wider rear dropouts, the angle of the driveside chainstay relative to the centerline of the BB is greater, meaning that clearance for larger chainrings is reduced. This problem is compounded when using the shorter spindle required to achieve a proper chainline; while many geared frames have dimples in the driveside chainstay to allow clearance for the inner ring of a double, these dimples are often placed and sized to accommodate a 42 tooth chainring at most, while a typical fixed gear application uses 46T chainrings or larger.
One solution is to move the chainring to the outside of the crank arms and find a 130mm track hub to give you a more appropriate chainline. Alternatively (but less desirably), you could use spacers to move the 120mm hub more towards the drive side, and then re-dish the wheel.
Probably the cheapest solution is to use the largest chainring that will clear the stay, and then size a rear cog appropriately. After all, 40x14 is just about the same gearing as 46x16.
Hope this helps.
10-12-10, 02:28 PM
10-12-10, 02:31 PM
10-12-10, 10:47 PM
I took a 5lb hand sledge and a piece of 1/2" rod and pounded the side of my chainstay the other night - it gave me the couple extra millimeters clearance that I needed. It doesn't look pretty, but it works. Of course, some touch up paint is needed before the roads get salted.
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