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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 05-19-07, 10:02 PM   #1
Jagee
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Single Speed Problem

I've converted an old peugeot to singlespeed--eventually it'll be fixed, when I can afford a new wheel, etc. Until then, I've taken off the freewheel w/cogs and replaced it with a 16t BMX freewheel. I shortened the chain and, using the original outer cog on the crankset, put together what looked like a beautiful 52-16 (16-52?). I was so psyched. I took it out to test ride immediately.

With each downstroke on the cranks, the rear wheel was somehow pushed out of whack. The whole wheel was pushed into the left rear fork with the pressure on the pedals and with the wheel at that angle, the chain even seemed to skip teeth on the rear cog.

When not pedaling, the rear wheel is good. The chainline is straight and the chain sits well on the teeth of the BMX freewheel. Is there any way to stabilize the rear wheel? Is something else going on? Let me know what you think/what I'm doing wrong or if this has happened to anyone else. Thanks for any suggestions or ideas.
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Old 05-19-07, 10:05 PM   #2
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I might be reading this wrong, but is your rear wheel fully tightened down?
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Old 05-19-07, 10:06 PM   #3
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Yeah. Your wheel obviously isn't digging into the dropouts enough to stay put. How tight do you have the quick release?
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Old 05-19-07, 10:11 PM   #4
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maybe you are genetically gifted and should go pro
?
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Old 05-19-07, 10:11 PM   #5
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I had the same thing happen to me when I first converted my Univega to a SS. The problem I had was that I left the freewheel on the rear wheel, just left the chain on the 16t cog and shortened it accordingly. As I was riding around just afterwards, the chain jumped to the next biggest cog, and since it was a larger gear, it pulled that side of the axle towards the front and I pedaled, and the wheel did what yours is doing now. It happened a couple more times when I was riding the next day, and I ended up bending the rear axle.

It sounds to me that you arent tightening the rear axle enough. Do you have a quick release rear axle? I had those cheapo locking type skewer things which are hard to get tight enough. You can always rebuild the rear hub with a solid axle which are like 10 bucks, along with track nuts which will allow you to get the rear axle really tight.
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Old 05-19-07, 10:13 PM   #6
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Ehh........get some knurled "track" washers
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Old 05-19-07, 10:49 PM   #7
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will do. Thanks.
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Old 05-19-07, 10:50 PM   #8
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no problem dude

wave to us from the podium!
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Old 05-19-07, 10:56 PM   #9
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I do have a quick release--I had kind of cranked on it to tighten it down as much as possible but will try to squeeze more out of it to see if that's the problem--I guess it must be. I think I do have one of those skewer deals and will take your advice and check out a more solid axle and track nuts so I can get it real tight. Thanks so much for your suggestions.
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Old 05-20-07, 04:48 AM   #10
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did u redish the rear wheel??? that could be your problem... make sure the chainline is straing
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Old 05-20-07, 11:22 AM   #11
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ditch the QR and get one of those hex axles. I got one at my LBS for $5. You can tighten those things down waaaaay more than a QR.
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Old 05-20-07, 11:31 AM   #12
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Or make sure you have a good QR. The shimano QR are usually good.

Also, you may have a dropout that is really hard steel. This will lead to slipping. The allen key QR replacements will work well for those.
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Old 05-20-07, 11:34 AM   #13
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just a shot in the dark, but if you used the old chain it may be the wrong size for the bmx freewheel? also, i've heard of problems arising from switching a well worn in chain from its original cog to a brand new one, the chain and small cog wear together and can be tempermental when you take away its 'mate'
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Old 05-20-07, 11:56 AM   #14
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If the problem persists you can always mod a bmx chain tensioner to work with your horizontal dropouts.
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