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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 10-28-02, 10:33 AM   #1
Brian_T
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Adjusting fixed-gear chainline

I've started turning my own wrenches on this old fixed gear and after overhauling the rear hub this weekend I noticed the chainline is far from optimal.

Sheldon Brown talks about adjusting the chainline with axle spacers but I don't fully understand what he means.

I am running a Suzue track hub (high flanges) with a Mavic rim that has virtually no dish. I tried moving the entire axle farther to the left but that did little to give me the line I wanted.

Any advice?

Thanks in advance,
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Old 10-28-02, 01:46 PM   #2
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Which way does the the chainline need to move? That is, which way is it out of line? Sprocke inboard of chainring or vice versa? The spacer method will allow you to move the sprocket more toward the non drive side, ie sprocket more inboard. Moving the axle back and forth doesn't seem like it would do anything. The hub will still be in the same position relative to the dropouts. Are you using a true single crank or a double crank with one chainring? If a double, do you have the chainring on the outside or inside of the spider? I put mine on the inside of a double crank and got a pretty straight chainline even with a 113 mm bb spindle. What about the bb? Was this bike originally a road bike set up for double cranks? If so your bb spindle may be too long.

If I could see your setup I might have some ideas. Hope some of this helps.
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Old 10-28-02, 02:40 PM   #3
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Your problem is probably with the crankset instead of the hub. If your using track hubs, your limited in adjustment. Are you using a double crankset with the chainring on the front of the spider? If so, move it behind the spider(where the small ring usually goes). If you're already on the small ring side, you might have to change BB length. hIf you're using a track crankset, you should be using a 109mm bottom bracket.
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Old 10-28-02, 03:12 PM   #4
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Thanks guys. This is an old Trek 330 road bike converted to fixie.

The chainline may be in the acceptable range (now that I've done some more reading on the subject) but the cog ideally would move more to the drive side to straighten out the line.

I have the 48 chainring on the outside setting of a double Ultegra crank and I expect the BB is also too wide.

I know the bike's not perfect but I'd like to get it as close as possible mechanically without losing the fun aspect (or the CHEAP aspect--which is nearly lost already.)

I suspect I can ride it with the existing chainline without a problem but, after riding the chain into the rear wheel after leaving one link too many in the chain, it's better safe than sorry. Fortunately I was wearing regular shoes and was riding down the driveway to pick up the paper. What?! Like you've never ridden your bike 20 feet just 'cause you could before?
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Old 10-28-02, 03:15 PM   #5
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Brian, move your chainring to the inner part of the spider and your problem will be solved.
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Old 10-29-02, 08:06 AM   #6
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Brian_T

Sheldon Brown has an awesome article on Fixed Gear conversions. Here’s a direct quote:

"I usually check the chainline by installing the hub in the bike, with no chain installed. By placing my head just in front of the chain wheel, I can sight along the chainwheel and see back to the rear hub, to see if the chainwheel lines up exactly with the rear sprocket. If it doesn't, I re-arrange spacers or change the bottom bracket axle as necessary.

Usually, on a bike that came with double chainwheels, the inner chainwheel will be more in line with the rear sprocket. If you wish to make the bike a pure fixed gear, you can buy a set of shorter "stack bolts" (the 5 bolts that hold the chainwheel(s) to the crank spider). You may find it easier to locate these in a shop that deals in BMX bikes."

Please review Sheldon’s article in its entirety at:

http://www.sheldonbrown.com/fixed-conversion.html
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Old 11-30-06, 11:58 PM   #7
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Nobody will ever read this post. Mwah ha ha--ah whatever.
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Old 05-25-07, 11:25 AM   #8
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Quote:
Originally Posted by cointelpro
Nobody will ever read this post. Mwah ha ha--ah whatever.
Lem's law
Nobody reads anything; even if he reads something, he does not understand it; even if he understands, he immediately forgets.

Last edited by noahjz; 05-25-07 at 11:39 PM.
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Old 09-04-10, 06:22 PM   #9
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I was about to read it, but I realized how old it is and stopped.
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Old 09-04-10, 07:38 PM   #10
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Sick thread bump
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Old 09-04-10, 11:11 PM   #11
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An 8-year old thread???
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Old 09-04-10, 11:19 PM   #12
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I'm posting in an eight year old thread! This was created before I could even type! almost.
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