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Bb help!!!

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Old 10-08-11, 12:21 PM
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Boom13
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Bb help!!!

I am building a fixed gear using a 1986 Univega Custom 10 frame set. I purchased this bike without any components for $10 as I wanted it for a winter project. I have never delt with bottom brackets before so when I initially measure the BB Shell and found it to be 70mm with English thread, I didn't exactly know what I was getting into. I am considering using a 73mm BB with spacers but I am concerned with what spindle length to use. I don't have cranks or hubs yet and have read that spindle length has a lot to do with the chosen crank set. I would just like to be as close to a straight chain line as possible. If anyone has any advice on how I should handle this issue it would be greatly appreciated and I thank you in advance for your help.
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Old 10-08-11, 05:13 PM
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Jeff Wills
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I'm 99.999% certain that your Univega has a standard English-thread bottom-bracket shell: 68mm wide, left thread on the right side. A 70mm wide BB shell would be an extraordinary mutation, something like a cow with 10 legs.

Figure out what cranks you're going to use, then get an English BB to match. It'll fit.
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Old 10-09-11, 10:45 AM
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Boom13
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I appreciate your help. This thing is something like a ten legged cow. 70 mm for sure. Started with a ruler, went on to digital caliper, and then to LBS. Craziness with the Univega Custom 10. Thanks again.
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Old 10-09-11, 12:47 PM
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Regardless of the BB size, would decide what crank (square taper, octalink, ISIS, HT2) you want to use before getting the BB. The type of BB you need (not size) is determined by the crank, so you need to decide this first.
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Old 10-09-11, 02:52 PM
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Jeff Wills
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Originally Posted by Boom13 View Post
I appreciate your help. This thing is something like a ten legged cow. 70 mm for sure. Started with a ruler, went on to digital caliper, and then to LBS. Craziness with the Univega Custom 10. Thanks again.

Pictures or it ain't for real. However, with most "cartridge" type bottom brackets, the width of the BB shell is irrelevant, since the cartridge uses internal stops to fix the BB in place.
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Old 10-10-11, 08:41 AM
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It could be that the bottom bracket shell wasn't faced to 68 mm when it was manufactured. That wasn't so important back when the bike was made since the extra 2 mm could be easily made up using the lockring and screwing the cup in a bit further. If you'r planning on using an external-cup style BB or a cartridge, then I'd go to the LBS and have it faced to 68 mm. If you're going fixed, then the old original cup-and-cone style bottom brackets were reliable and smooth like butter with a little maintenance, and I wouldn't change it. Chainline was controlled by axle length. But I'm a luddite and I like old stuff.
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Old 10-10-11, 10:50 PM
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Originally Posted by cycle_maven View Post
It could be that the bottom bracket shell wasn't faced to 68 mm when it was manufactured. That wasn't so important back when the bike was made since the extra 2 mm could be easily made up using the lockring and screwing the cup in a bit further. If you'r planning on using an external-cup style BB or a cartridge, then I'd go to the LBS and have it faced to 68 mm. If you're going fixed, then the old original cup-and-cone style bottom brackets were reliable and smooth like butter with a little maintenance, and I wouldn't change it. Chainline was controlled by axle length. But I'm a luddite and I like old stuff.
+1
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