Bottom Bracket sizing question.

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mtnbiker7

New Member
I'm looking at buying a new crankset for my dj bike but don't know what size I need. Basically what I'm trying to figure out is how to know the size BB. Here is what I pulled off the old bottom Bracket.

BB-TY30
Shimano
Bc 1.37 x 24(or 137 x x 24 not sure)
VA 68 EC
 
M

mtnbiker7

New Member
I'm going from a square taper to an octalink. Does that matter? Does it matter if I get a bigger bottom bracket then 122 (now 122mm 68mm)? I still need the 68 mm but go up to a 126 possibly.
 
goodvibe

goodvibe

Well-Known Member
the 68 refers to the bottom bracket shell length. the 122 refers to the spindle length. A lot of the newer bottom brackets include spacers to make it fit both 68mm and 73mm shells. This bottom bracket comes in four sizes:
68x115
68x122.5
68x127.5
73x127.5
I am assuming that you have a new crank that is compatible with the Octalink bottom bracket. The octalink bottom bracket will not be compatible with the square taper crank.
 
M

mtnbiker7

New Member
goodvibe said:
the 68 refers to the bottom bracket shell length. the 122 refers to the spindle length. A lot of the newer bottom brackets include spacers to make it fit both 68mm and 73mm shells. This bottom bracket comes in four sizes:
68x115
68x122.5
68x127.5
73x127.5
I am assuming that you have a new crank that is compatible with the Octalink bottom bracket. The octalink bottom bracket will not be compatible with the square taper crank.
Click to expand...

I'm getting a new deore single speed crank with a new bottom bracket but what I'm asking is if I need the new bottom bracket to have the same spindle length? Would 4mm's bigger or smaller be ok for the spindle lenght?
 
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