Road Cycling - Difference between 3 bottom brackets???

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zman92atl
10-01-03, 09:59 AM
I need to order a bottom bracket for the Shimano 105 double crank I just bought. I see there are 3 different models to choose from, ES51, ES71 and a 5500. What is the difference between these models and how do you determine the proper length??? Although this probably won't help, I have a 50cm frame and I will be using a 170mm crank arm. The tooth count is 53t-39t and it is the newer 105 crank. Thanks in advance:)

mrfix
10-01-03, 10:25 AM
If you bought a 5500, 105 shimano with the octalink spline, you will nee a BB5500, or BB6500 109.5mm, you need to measure your frame width at the bottom bracket shell to see if you need a 73mm or a 68mm . So a 68X 109.5 or a 73X109.5. The ES 51 or ES71 will not work with the 105 because it has a V2 spline, the 105 uses the V1 spline, it has a shorter engagement spline then the V2.
TimB
10-01-03, 10:27 AM
ES = Extended spline and is mainly for MTB's

all the road cranks use BB5500 (105) or BB6500(ultegra) or BB7500 (Dura Ace)

zman92atl
10-01-03, 10:28 AM
Thanks for the quick response, yes I already know I have a 68 and forgot to mention that. I was mainly interested in the length. Thanks again.