Huh, I used to commute on a mountain bike in Somerville, MA. There were a couple of sections where I normally hit 20-25 mph on downhills. (Ones with no side roa

Huh, I used to commute on a mountain bike in Somerville, MA. There were a couple of sections where I normally hit 20-25 mph on downhills. (Ones with no side roads to the right, and no tight corners.) I wouldn't have wanted to wipe out or go over the handlebars at that speed. But on a familiar road, with 26" knobby tires and a front suspension, I had reliable control. The gyroscope effect of mountain bike rims is substantial at 25 mph. And a mountain bike is usually fine even on awful pavement, especially for someone who also rides in the woods. The biggest danger by far in that scenario was Boston drivers. All the injuries I ever heard of were cars doing something illegal, or people getting doored on the Central Square bike lane. Overall, the statistics are pretty decent for experienced cyclists, if they're riding their daily commute and obeying traffic laws. For an ebike, I'd want to stick with max 20mph pedal assist, and full size tires. And I'd want something I could ride onto a soft shoulder at full speed. So probably knobby tires and a front shock? If I can't drop 2" onto a sand shoulder, then I'm going too fast.