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I have just finished my first fixed gear based on an old Raleigh Rapide frame. But the chain line is off and I hear a crackling/ticking noise when I pedal.

The wheels are replace with a gipiemme wheelset and I kept the old bottom bracket and crank/chainring combo. The chainline is off by a few milimeters.

I have created an image that shows the issue: Chainline

My first guess is to replace the spindle/axle. Are they sold seperatly from the cups? The current spindle is asymetric (longer on the driver side), but for a single speed bicycle I could probably buy a symetrical one right?

How can I find out which spindle I should get?

What other options do I have?

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With some of the older BB designs you'd be able to adjust the cups to a degree, but only if the "fixed" cup has a lockring rather than being a single piece. You'd probably have to discard the lockring and rely on thread lock compound on that side, to run the cup in a couple more mm. (Note that a symmetrical BB would move your chainring to the left, so something is odd about your setup -- possibly the crank arm.) –  Daniel R Hicks Dec 13 '11 at 13:12
    
Unfortunately, the fixed cup does not have a lock ring. You are right that a shorter spindle would make the chainring move to the left. But, I am currently using the inner spider/chainring, and could use the outer spider/chainring instead, which might get in line with the rear cog by using a shorter spindle. What are your thoughts on that? –  Koen Dec 13 '11 at 13:31

3 Answers 3

I would surely go by changing the bottom-bracket for a longer one (be it changing the spindle as you said, or installing a sealed Shimano-type one).

If you don't want too much to keep your current bottom bracket with separate spindle and cups, the sealed one is much more reliable, long-lasting, play-free and water-resistant.

To find out the correct size is not a trivial task, I think you should go talk to some friendly and experient bike mechanic, since there are some subtle factors involved in bottom-bracket crankset interaction, that determine the final position of the chainring.

If your spindle looks long, get a shorter one and move the ring to the outer side of crank spider. If your crank is already very close to the frame, find a longer bottom bracket.

OR

You could play with the wheel/cog position,sometimes there are washers and nuts around the bearings that can be moved, swapped, changed for thinner/thicker ones, etc. I have a fixie with a very cheap rear hub, and there is a lot of dishing, but I don't care, I've ridden dished wheels my whole life and they worked. It is not prettiest, but it is a minimal problem compared to twisted chainline on fixies/singles.

Hope it helps!

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Your other option is to move the chainring. I don't know what your cranks look like, so it may not be practical, but maybe you can add some spacers underneath the chainring mounting bolts. This may also require longer bolts.

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if you have a double chainring crankset, and are just running one ring, on the inside of the crank, you could try moving the chainring to the outside of the crank (where the big chainring would have been). Also - what is your chain tension like? The noises could also be attributed to a very tight, very cheap KMC chain. you should have about 1/4" "sag" or "vertical play" in your chain at the tightest point. It also helps to have a single speed chainring, as it is made to fit with a single speed chain (which is wider than a 6,7,8 spd or 5 speed chain). That might resolve the misaligned chain.

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