What Bottom Bracket Size?

will_85

I'm replacing my bottom bracket, but i'm slightly confused as to what size I need. (Shimano UN55 Square taper)

When I measure the length of the bottom bracket shell on my bike it measures 68mm wide, but when looking at the old BB I removed, when assembled (off the bike) it measure 73mm, face to face. I know the spindle length is 110mm.

So.... do I need a 68x110 or 73x110?

drlodge

According to Sheldon, 68mm is English and 73mm is English Oversized, these measurements refer to the "shell width" if that helps.

supersonic

What chainset do you have? And what frame?

will_85

drlodge wrote:

According to Sheldon, 68mm is English and 73mm is English Oversized, these measurements refer to the "shell width" if that helps.

Thanks!

supersonic wrote:

What chainset do you have? And what frame?

Frame is a 2004 Kona Cindercone, Shimano Deore triple, but converting to single.

BB removed was a UN25, but looking to upgrade to UN55

http://www.chainreactioncycles.com/shim ... -prod71369

supersonic

Need the exact model number of chainset. Should be written on back of crank arm.

will_85

supersonic wrote:

Need the exact model number of chainset. Should be written on back of crank arm.

FC-M440

supersonic

110mm is correct - double check the shell width of the frame, and go for whatever it measures.

will_85

Thanks for your help