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10-04-09, 05:24 PM
There must be previous threads about this, but I can't find them. I'm converting a cup and cone bottom bracket from a double to a triple. It's Sugino bb, for a 68 mm shell. The existing spindle is a 30-52-30, overall length 112. To convert to a triple, I would ideally use a 30-52-35 spindle, as I know from taking direct measurements with the crankset I'm going to use.
That's an overall length of 117. But if I go with a cartridge bb instead, a 118 would be too short, yes? Because all cartridge BBs are symmetrical? Am I correct in assuming that in order to get the length I need on the drive side, I would need the equivalent of a 35-52-35, or a cartridge BB with an overall length of 122? That means I have 5 mm more than I need on the drive side, but that's life, right? Or am I misunderstanding how all this works?
I'd prefer to stick with the cup and cone bottom bracket if I can find one the right length. But I may go the cartridge route instead. I recently bought NOS 32-52-35 spindle on ebay, but the guy is taking his sweet time about sending it--I wouldn't be surprised to find myself out both the 13 bucks and the spindle.
That's an overall length of 117. But if I go with a cartridge bb instead, a 118 would be too short, yes? Because all cartridge BBs are symmetrical? Am I correct in assuming that in order to get the length I need on the drive side, I would need the equivalent of a 35-52-35, or a cartridge BB with an overall length of 122? That means I have 5 mm more than I need on the drive side, but that's life, right? Or am I misunderstanding how all this works?
I'd prefer to stick with the cup and cone bottom bracket if I can find one the right length. But I may go the cartridge route instead. I recently bought NOS 32-52-35 spindle on ebay, but the guy is taking his sweet time about sending it--I wouldn't be surprised to find myself out both the 13 bucks and the spindle.