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Old 02-03-06, 04:32 PM
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11.4
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You may have a couple different things going on here.

First, about the BB length. It's actually pretty difficult to deform the cranks enough so they actually move farther onto the bottom bracket (more common is that they don't sit square any longer, so the chainring veers in and out as you rotate the cranks). You may have a mismatch between axle and crank. These cranks were made in both ISO and JIS standards (which differed in the angle and precise dimensions of the taper on the spline). The cranks weren't marked as to the correct taper and most bottom bracket axles weren't either (you usually had to depend on the brand to tell you, but even that didn't often work). Anyway, if your cranks are sitting straight so the chainring runs in a straight line, it's easily fixed. You can get a bottom bracket spacer ring in various thicknesses (0.5 mm up to 3 or 5 mm) from a bike shop (it happens to be the same diameter as spacers for your rear hub cog, so a couple extras in your bag will always help with fixing chain line on a new hub). You'll remove the right bottom bracket cup and reinstall it with the spacer in place. The left cup will typically have several millimeters of extra threading beyond the lockring, so you can add spacers up to the amount of threading you have available. If you by any chance start having your left crank arm hit the left chainstay, then you will unfortunately have to get a longer bottom bracket, but this isn't normally the case. Do note: If you've pushed your chainring out farther, be sure that your chainline is still good -- you don't want to fix one problem and have your chain want to come off. You might have to use another spacer between your rear cog and your hub to keep the chain running straight.

In the off-chance you need a new bottom bracket, you'll have to identify whether your crankarms are in fact ISO or JIS, and whether your bottom bracket axle was mismatched. A good machine shop will have templates for measuring which angle of taper you have, but don't expect a bike shop to do it. The simplest way to get a JIS bottom bracket in a longer length, if you need one, is to call Phil Wood and talk to Brent. He can give you just about anything you need. They aren't cheap, but they're guaranteed to be the last bottom bracket you ever need, and indeed the last one you'll ever have to service again.

About the creaking: Are you standing in trackstands? I ask because this is an odd time to get creaks if you're sitting. As you probably know, creaks can come from all parts of the bike and will often appear to be coming from other places. If you're sitting, I'd focus on your saddle and your seat post-to-saddle clamp (a little grease on the saddle clamp might make it go away). If you're standing, it could be your bars or levers, or even more likely in your cleats (since you're putting more weight on them and probably twisting them just a little bit as you stand). I assume your chain is clean and lubricated, so it isn't just squeaking from accumulated grime and dryness.
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