Did I buy the correct bottom bracket?
 

Hello everyone. My current bike has a square taper BB and I need a Octalink BB since I'm swapping my crankset.

Chin Haur Square Taper is CH52-68 BC 1.37.24T 111L
Shimano Octalink is 68 BC1.37x24 109.5

I have no idea what these specs completely mean but i'm assuming it all matches up except the width on the new one is 1.5mm narrower. Will this still work?

The new bottom bracket has to match the new crank. The required spindle width is defined by the crank, not by what was already there, so make sure thats what the crank requires.

Incidentally, Octalink is long obsolete.

If I understand you correctly, yes the bb and crank matches. I purchased the Octalink bottom bracket along with the Shimano 5500 105 which is Octalink compatible.

BB shell width is the 68, 1.37x24 means its British thread standard (near universal)

the last numbers are the overall lengths of the 2 types of spindles

Shimano's octalink needs a matching shimano crank, a proprietary 8 spline pattern ...

Would the overall lengths be an issue if the newer one is 1.5mm shorter?

I'm not worried about compatibility. The Crank and BB came together as a combo brand new. Both are 105 5500 series.

You should be fine. The 5500 series Octalink V1 (which is different from other Octalinks commonly used on MTB & a few Road cranks) uses a 109.5 for the double and 118.5 for the triple. As long as your frame is quite "standard" there shouldn't be any issues.

Thanks! I'll try installing it tonight

So you have the BB tools/?

Yes, the FC-5500 does use an Octalink (V1) bottom bracket and the 109.5 mm length is correct for the double crank. There was a 118.5 mm version used for the 5503 triple crank.

Whoops, I just noticed KCT1986 provided the same information but got there before me. At least you now have two confirming postings..

Thanks everyone. Just installed it and everything is good. I didn't even have to adjust the FD.

Yes