Originally Posted by
T-Mar
The design predates the CPSC, going back to at least the mid-1960s. However, it would provide a similar benefit in cases where people might be switching between side-pull and centre-pull brakes and installing or removing a headset mounted cable hanger.
Thanks. OK, the extra lock nut was originally for the cable hanger then. That feature certainly did come in handy a few years later when CPSC reflectors became the norm. Removing reflectors was more common than swapping brakes.