I have a decent street/mountain 7-speed bike with clamp-pad-(old)style brakes. Is that enough stopping power, or should I just bite the bullet and buy a (maybe used) bike with disc brakes?
Strap 20 pounds to yourself or your bike to simulate the additional weight of the ebike components and find a hill that will get your speed up to 25mph to simulate the speed of an ebike. See how your brakes perform.
Check out Johnny video, talking about this: E-bike Blog: Are rim brakes on an e-bike ok? - YouTube
Strap 20 pounds to yourself or your bike to simulate the additional weight of the ebike components and find a hill that will get your speed up to 25mph to simulate the speed of an ebike. See how your brakes perform.