Type A or Type B chainrings?

[antiquepedaler]

Does anyone know if there is any difference in using either Shimano Ultegra Type A or Type B chainrings as replacements on the idler side of a tandem? In shopping around I see both but no explanation of the difference.

[TandemGeek]

Does anyone know if there is any difference in using either Shimano Ultegra Type A or Type B chainrings as replacements on the idler side of a tandem? In shopping around I see both but no explanation of the difference.

It hardly even matters on the drive side.

In Shimano's pursuit of "perfect shifting" it created matched sets of chainrings for it's STI bikes, e.g., 52/39 A-type rings and 53/42 B-type rings or something like that... I'm going from memory here. The ramps and pins are positioned to optimize the upshifts and downshifts for the different pairs but, in practice, folks have mixed and matched A-type and B-type rings with no perceived difference in shifting performance, perhaps even less dramatic than using a SRAM chain on a Shimano drive train.

[antiquepedaler]

It hardly even matters on the drive side.

In Shimano's pursuit of "perfect shifting" it created matched sets of chainrings for it's STI bikes, e.g., 52/39 A-type rings and 53/42 B-type rings or something like that... I'm going from memory here. The ramps and pins are positioned to optimize the upshifts and downshifts for the different pairs but, in practice, folks have mixed and matched A-type and B-type rings with no perceived difference in shifting performance, perhaps even less dramatic than using a SRAM chain on a Shimano drive train.

Thanks, Mark!

Jay