Riders keeping an older Octalink road bike running, with a 68 mm English-thread shell and a double crankset.
The BB-5500 is the Octalink bottom bracket from Shimano's older 105 road group. It is a sealed cartridge unit with a hollow steel spindle, so the bearings and axle go in as one piece and the splined crank arms locate straight onto the spindle ends.
This is the 68 mm English-thread version with a 109.5 mm axle. It suits the original Octalink (V1) road cranks, such as the 105 FC-5500, Ultegra FC-6500 and Dura-Ace FC-7700 series, so check your crank model, your shell width and your thread before you order.
Hollow Octalink spindle
A hollow steel spindle with splined ends, made for Octalink cranks.
Sealed cartridge unit
The bearings are sealed inside the cartridge, so the whole unit fits and replaces as one part.
68 mm English thread
BC1.37 x 24 threading for 68 mm shells. The 70 mm Italian (M36) version is a separate part.
109.5 mm axle for doubles
Shimano lists 109.5 mm for double cranksets and 118.5 mm for triples.
Fit
Build
Great for
Maybe not for
Check three things: a 68 mm shell, English thread (BC1.37 x 24) and a 109.5 mm axle for a double crankset. Shimano also made the BB-5500 in 70 mm Italian thread and with a 118.5 mm axle for triples, and those are different parts.
Match the spline generation
Octalink came in two versions. The BB-5500 is the V1 road type, which pairs with cranks like the 105 FC-5500, Ultegra FC-6500 and Dura-Ace FC-7700. The V2 spline used on mountain bike Octalink cranks is not the same, so read the model number on your crank arm before you order.
