Bicycle Mechanics - Shimano BB 6500 BC 1x37 68 CB

Hello, I'm looking to buy a replacement for the aforementioned Bottom Bracket, any one know where I can still buy this item?

The "BC 1.37" is the threading designation and is the very common English threading. The "68" is the bottom bracket shell width in mm and is the standard for English threading too. I presume the "CB" stands for cartridge bottombracket. Your crank has a JIS taper but these are very common also.

So any English threaded square taper bottom bracket of the proper spindle length is what you need. IIRC, the Ultegra 6500 double crank required a 115 mm spindle length but a 118 mm will also work without compromising the chainline too much. Check with any LBS or Loose Screws has Shimano UN 54 bottom brackets for only $20.

The "BC 1.37" is the threading designation and is the very common English threading. The "68" is the bottom bracket shell width in mm and is the standard for English threading too. I presume the "CB" stands for cartridge bottombracket. Your crank has a JIS taper but these are very common also.

So any English threaded square taper bottom bracket of the proper spindle length is what you need. IIRC, the Ultegra 6500 double crank required a 115 mm spindle length but a 118 mm will also work without compromising the chainline too much. Check with any LBS or Loose Screws has Shimano UN 54 bottom brackets for only $20.

The 6500 is Octalink, not square taper, and the double is 109mm. The UN54 (square taper) won't work.

Shimano quit making the BB-6500 when they went to 10-speed with the external bearings. The 105 (BB-5500??) is still available and will work just as well. You could also go to the Dura Ace (7700 series), but it has roller bearings that require closer tolerances and more maintenance.

TF

The 6500 is Octalink, not square taper, and the double is 109mm. The UN54 (square taper) won't work.
Whoops again. :( You're right and I got lost in Shimano's numbering system. The 6500 series is the 9-speed and is Octalink. I was thinking of the 6400 series which was square taper.

The threading is English on the OP's bottom bracket so I at least had that right.

Thanks, I ordered the D.A. BSC68x109 replacement from Excel Sports...

Thanks, I ordered the D.A. BSC68x109 replacement from Excel Sports...
As TurboTurtle noted, the DA Octalink bb is not a set-and-forget sealed unit like the Ultegra and 105 level bbs. It will require both adjustment and relubricating at reasonable intervals to keep it going, particularly if you ride in any other than ideal dry, clean conditions. I recommend you read the installation instructions to be sure you know how to take care of it.

Thanks, I ordered the D.A. BSC68x109 replacement from Excel Sports...

Unless your bottom bracket shell is precisely machined, both the threads and the end faces, and preferably with the Campagnolo cutters, the Dura Ace bottom bracket WILL NOT run smooth and will fail after very few miles. It is probably the most finicky bottom bracket that has ever been made. Very few frames come from the factory with the BB shell machined to close enough tolerances for that particular Dura Ace bottom bracket. If your frame is from a top American builder like Richard Sachs or Peter Mooney (there are quite a few others too) the shell will be properly machined and you can just go ahead and install it with no worries. Otherwise, be forewarned. For most frames, the 105 is a much better option. If you have a shop nearby with the Campy cutters, bring the frame in and ask them to install the thread guides. If the thread guides don't BOTH go in together, the shell needs work.

Thanks, I'll take that into consideration.

If your frame is from a top American builder like Richard Sachs or Peter Mooney (there are quite a few others too) the shell will be properly machined and you can just go ahead and install it with no worries.

My frameset is custom built by Joe Williams of Williams American Cycles (formerly based near Glens Falls NY) in 1990. Anyone know if he's still in business?