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TH bottom bracket compatibility

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TH bottom bracket compatibility

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Old 08-15-10, 04:11 PM
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Slodad
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TH bottom bracket compatibility

The crank flops about in my bottom bracket. The BB is a TH BB-7700 68x116. Based on the price I've seen online, it must be a pretty lowend product. Is there something similar that is more robust or lighter for not a whole lot of money? The bike is a Fuji Finest AL, so I don't want to go wild with an upgrade, but I figure that a $14 alternative might be superior to the $4 TH.

Is there some way to tighten the crank in the cartridge? There is a 8 sided nut on the drive side that looks like it might be used for adjustment. Not having an 8 sided socket, I'm not sure how I'd go about adjusting it, and I'm certainly not going to spend much on a tool to fix a $4 product. Mostly, I'm just curious.
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Old 08-16-10, 10:58 AM
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Looks like it's a regular square taper BB so finding an upgrade will be easy. A Shimano UN54 BB (around $25)would be a good, inexpensive option but there are plenty of other options out there. You'll need a crank puller as well as a tool to remove and intall the BB. Not sure what the 8 sided nut is. There should be either an allen or nut holding each crank arm in place and they should be 6 sided. If the problem is loose crank arms (as opposed to a worn BB), you can try tightening them up but they usually can't be saved if ridden very far when loose.
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Old 08-16-10, 11:05 AM
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The only BB the OP needs to consider for a replacement is a shimano cart. MSRP $20. And it'll be a 68 (english) model with a 115/118 spindle length. The OP also needs to determine the effective chainline for that TH bb. For example is it asymmetrical? Will it match up with the same length shimano bb or will you have to account for the difference?
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Old 08-16-10, 11:14 AM
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'Flops about' sounds like arm damage.
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Old 08-16-10, 01:30 PM
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Problem is definitely a loose spindle. After removing the cartridge, I'm able to wiggle the spindle inside the cartridge. Looks like a visit to LBS to pick up a new Shimano. Thanks for the help.
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