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Chainline help with fixed cog I just added to my singlespeed(5 posts)

Chainline help with fixed cog I just added to my singlespeedjustina
Feb 11, 2003 10:43 AM
I installed it only to find the chainline is off (fixed cog is about 1.5mm closer to the wheel than the free was, thus the narrow link rubs the inside of the teeth and "pops" off the cog. Figured I'd just move the chainring to line up with the fixed as I prefer fixed and ditch the free altogether. Problem is the chainring needs to move in and it can't, moving to the inside of the spider puts me too far the other way. It's a dura ace Octalink so I can't tighten the crankarm a little deeper onto the spindle either. I've been told not to put a shim between the fixed sprocket and the hub, but can't think of a good reason why it's OK to do it with a freewheel, but not the fixed cog. The other option is to mess with spacers on the axle, but this means redishing the wheel. What's the solution here, help? Thanks,

Justin
Aw, just slap a washer or spacer on the axel and see ...Humma Hah
Feb 11, 2003 3:29 PM
... what happens. 1.5 mm is about the thickness of a heavy duty steel washer. Depending on the spring of your stays, 1 or 2 such washer thicknesses should nudge it over just enough.

And 1.5mm should not be enough to require a redish, unless you have rear brakes and want 'em REALLY close. On a fixie setup you can leave the rear brakes set wide, as you probably won't use them much.
re: Chainline help with fixed cog I just added to my singlespeedDave Hickey
Feb 11, 2003 5:15 PM
Have you tried a shim? Better yet, do you have an old bottom bracket lock ring? It's threads are the same as the hub. Screw it on and then the cog and your chain line should be better.
Have you checked the LBS?Straightblock
Feb 12, 2003 8:50 AM
Older LBSs or ones that deal in BMX may have spacers to put behind your cog. Back in the days before cassettes, shops used the spacers to adjust chain line issues or to move freewheels out to keep the rear derailler out of the spokes. BMX shops might still use these to set chainline with single freewheels. As long as the cog fully engages on the hub threads you shouldn't have a problem, unless you use a lockring. If you don't have enough threads exposed to install a lockring you can use loctite on the cog. Someone else here can tell you the correct type. I don't use loctite or a lockring and never break the cog loose, but I use 2 brakes, too.
re: Chainline help with fixed cog I just added to my singlespeedxxl
Feb 13, 2003 5:56 AM
I think you can use spacers just fine, especially a 1.5mm one. I'm surprised that the chainline's being off by that is making your chain pop, really; it's just not that much.

Are you using derailleur (3/32") chain, and is it possible that you've got a 1/8" track cog giving you compatibility issues? Just a thought.