bottom bracket & crank
04-13-15, 02:26 PM
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bottom bracket & crank sizing
I have found this frame that I am interested in (Fixie/Fixed gear/Single Speed Bike Frame with Fork Matt Black 52cm | eBay), but I have been confused by bottom bracket sizes. The frame says that it needs a 68mm-107mm bottom bracket (which i have found - Shimano BB-UN55 MTB / Road Bike Bottom Bracket 107mm | eBay). The question that i am asking is can i just put any square taper cranks on or do i have to get a set of cranks specific to the bottom bracket dimensions? P.S I know this is probably a really easy to answer question but this is my first foray into anything other than bmx.
04-13-15, 03:23 PM
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Depends on your REAR components. You want the front chain ring in the same plane as the rear cog. In general you can mount any square taper crank on any square taper axle (there are nuances), but the crank will have its own geometry.
So what's on the back?
So what's on the back?
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04-13-15, 03:24 PM
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BTW, is 52cm the right size for you?
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04-13-15, 04:24 PM
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You buy the BB to fit the crank used. Not the other way around.
04-13-15, 05:18 PM
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yes, the vast majority of modern square tapered double or single-speed road crank will fit.
i'm equivocating, but still... don't quote me.
i'm equivocating, but still... don't quote me.
Last edited by hueyhoolihan; 04-13-15 at 05:22 PM.
04-13-15, 05:33 PM
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Here's Sheldon Brown's database on bottom bracket compatibility with cranksets. It's not complete, but it's as good a source as I've found on this subject:
Sheldon Brown's Bottom Bracket Size Database
