Originally Posted by
robertorolfo
I read the entire thread, and the only thing is what you just mentioned: some "power modulator" that essentially acts as super simple anti-lock mechanism. So people were locking up the brakes, and essentially they are blaming the brakes as being too powerful?
An anti-lock brake has a lockup sensor; a power modulator just limits the torque irrespective of conditions, so it's not really the same thing.
Apparently a roller drum brake in contrast to other types just makes it too easy to unintentionally over-brake; while a highly skilled rider very in tune with their gear might be okay, the manufacturer doesn't want you running one without a modulator even on a
personal bike, and these were
share bikes targeted at an often inexperienced pool of riders and putting even experienced riders in a position of being unfamiliar with the unique feel of the particular example they would be getting on.
Seems like user error was just as much to blame here
Some of the crashes were cyclists of long experience
Citi Bike (or lyft, or motivate, or whomever runs the service) simply shot themselves in the foot by calling it a technical problem, thus opening themselves up to lawsuits.
Actually they held out and were silent about the issue until that became untenable.
As you stated before, govern the assist to 10-12 mph and all of the issues basically go away.
The traffic problems are vastly improved, but the brake problems exist even on a pedal bike that lacks a modulator, and predates e-bikes; it's just that the pedal fleet pairs modulator hubs with the roller drum brakes in accordance with the manufacturer recommendation.