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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 02-21-08, 08:40 PM   #1
savestheday
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Truvativ BB and Bulletproof crank problems!

Well, I've been riding my recently put together fixie for about six months now and have been dealing with a chainline issue. But the noise finally got to me and I switched the bottom bracket today.

original specs.
Bullet proof crank set with the chainring on the inner spider
According to Sheldon Browns (RIP) site I would have a chainline of 39.7mm with a 107mm BB.
So I used a 108mm truvativ one and the chainline came out real close to the calculated 40.2mm. 40mm by my ruler.

So I went in search of a 112mm BB at the LBS and they gave me a 113mm Truvativ. Well i threw it in and voila. No change in the chainline! That I can tell at least.

But the non drive side seems further out. I'm assuming that this is some mountain bike application and not what I need.

So my questions are.

Should I just try to make a 2mm spacer to put on the drive side cup?

Or should I get a new BB? If so what are you guys using with bulletproofs to get a 42mm chainline?

Thanks a lot.
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Old 02-21-08, 10:11 PM   #2
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You didn't, like, put the BB in backwards, did you? They're asymmetrical - the drive side is longer.
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Old 02-22-08, 12:40 AM   #3
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Quote:
Originally Posted by dmg View Post
You didn't, like, put the BB in backwards, did you? They're asymmetrical - the drive side is longer.
+1
there should be an "L" and "R" marked on the bottom bracket to show which side it should face.
It might just be the longer spindle that makes the non-driveside crank arm stick out some, is it causing any problems other than aesthetics?
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Old 02-24-08, 12:19 PM   #4
savestheday
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The drive side cup is made onto the BB itself. i assumed you couldn't put it in backwards. I did put 2mm worth of spacers on the drive side today and it helped a lot.
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Old 04-18-08, 08:55 AM   #5
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where did you get those spacers I want a decent chainline with a set of bulletproofs that I am going to get. Also how is the bottom bracket working out after a few months.
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Old 04-18-08, 08:57 AM   #6
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i don't think you can put that bb in backwards; it's english threaded, and the drive side cup isn't removable.
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Old 04-18-08, 09:20 AM   #7
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Bulletproof+sugino103 with 3/32ring on the outside(45mmCL)+1/8 chain and cog =non noisy drivetrain
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Old 11-17-08, 11:14 AM   #8
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wow this thread helped alot. i've just encountered the same problem. i thought when i switched from a 107mm shimano to a 113mm truvativ, my chainline problems had been solved (using bulletproof cranks). however, it looks like the 113mm is truvativ is actually a 108mm truvativ (or a 107mm shimano) with 5mm more on the non-drive side. my chainline is exactly the same as with a 107mm shimano.

guess i'm off to get some spacers myself.
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