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Singlespeed & Fixed Gear "I still feel that variable gears are only for people over forty-five. Isn't it better to triumph by the strength of your muscles than by the artifice of a derailer? We are getting soft...As for me, give me a fixed gear!"-- Henri Desgrange (31 January 1865 - 16 August 1940)

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Old 08-12-08, 09:45 PM   #1
powerband
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Converting a Double Chain-ring to a Single - Please Help

I have an old double-chainring crank set (Sugino Super Custom) that I want to use for my fixed-gear bike. I will be using the smaller chainring (42T), but I want to bring it from the inside of the spider arms to the outside. How can I do this and still retain a straight chain line?

So far, I don't have a bottom bracket installed in the frame, but should I bring the crank set (with the small chain ring on the outside of the spider arms) in to an LBS and let them figure which bottom bracket would be appropriate? Can the length of the bottom bracket be chosen to allow a straight chain line?

Any help will be appreciated, since I'm not familiar in this area!

Cheers.
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Old 08-12-08, 09:56 PM   #2
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I'm trying to do the same. Right now I'm either going to use washers to replace to thickness of outer chain ring or just cut off the part that the bolt goes through and use that, which would basically be a square washer.
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Old 08-12-08, 09:59 PM   #3
iwegian
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you could get bmx chainring bolts. i think they're 5mm
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Old 08-12-08, 10:16 PM   #4
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The original chain-ring bolts are short enough that they'll work. The problem is that when I move the chain ring from inside the spider arms to the outside (purely for aesthetics), this moves the chain ring about 5 to 8 millimeters out. Can I compensate for this displacement by selecting an appropriate (shorter) bottom bracket? I would like to retain the optimal chain alignment.

Thanks, again.
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Old 08-12-08, 10:24 PM   #5
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you can only go but so short. similar to issues w/ the RD crankset, the only real way to fix this is by purchasing a rear paul hub. other than that, it's either inside of the spider or a noisy drivetrain.
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Old 08-12-08, 10:28 PM   #6
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Originally Posted by sp00ki View Post
you can only go but so short. similar to issues w/ the RD crankset, the only real way to fix this is by purchasing a rear paul hub. other than that, it's either inside of the spider or a noisy drivetrain.
Thanks, sp00ki. The irony was that I was considering bailing on the old crank set and buy the Sugino RD.

I guess going on the inside might have to do, then.
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