ICE vs Electric Motor Transmissions

[wturber]

The Euro standard of three classes of ebike, with increasing requirements for safety equipment and licensing as power climbs past 250 W, makes a lot of sense.

I disagree. I think only two classes are needed. Max motor assist to 20 mph and 25-ish mph would define the two classes. You could have a 1500 watt limit for both and make life a lot easier and simpler for heavy riders, cargo bikes, etc. with little or no impact on safety. They seem to want to limit speed by limiting motor power. Nobody seems to do that with automobiles. Why should it be done with ebikes?

 

[Chalo]

They seem to want to limit speed by limiting motor power. Nobody seems to do that with automobiles. Why should it be done with ebikes?

I agree with you too. Nobody does it with cars and I'm sure they will never do that!

I think a universal road vehicle power limit would be a great idea for mitigating the harm done by motor vehicles, like "you can have 25kW; use it however you like". That would be an incentive to use only as big and heavy a vehicle as necessary, and it would keep the big heavy ones nice and slow, the way they should be. And it would incentivize moving freight by rail instead of road.

I think the overall implications of such a rule would be even better than the overall implications of a decent and humane speed limit on everyone, like "no motor traffic faster than 20mph within the city limits", sternly enforced. The latter approach would make for livable streets, but would not harness people's creativity in the service of efficiency.

 

[speedyebikenoob]

Bicycle sized vehicles can work well as a single speed provided they have +3kw of sustained power geared for <40mph.

With only 250-1000w they need gears.

My middrive is 2.5 kw so not quite 3 but I've tried riding it in 6th gear only which is geared for about 33 mph and it's much more sluggish compared to starting in first. Also overheats quite a bit more when used like that. Can't climb hills at all.

 

[Grantmac]

I should note in taking sustained 3kw, burst capability about twice that and 72v.

 

[classicalgas]

"You could have a 1500 watt limit for both and make life a lot easier and simpler for heavy riders, cargo bikes, etc. with little or no impact on safety."...there most definitely would be an impact on safety, the motor and battery allowing 1500w output would be something on the order of six times heavier (about a hundred pounds) than a 250w setup (given the same "marketing" range per charge) Impact energy goes way up, even at 20mph, if you add 30% to the bike/rider weight. You need better brakes, better tires...

And once you allow 1500w, you'd need firmware in the controller to to keep the bike below the legal speed limit, and soft start programing to keep the driveline happy and the tires from slipping under low traction conditions. How long until those limits were bypassed by "performance" riders? Some sort of hidden switch or smartphone app, so an observant LEO couldn't duplicate the extralegal behavior he just witnessed.

It wasn't uncommon, up until 40 years ago, to have ICE vehicles taxed based on their displacement or horsepower, so it's not at all out of the realm of legal precedent to put legal limits on power output for a given class of vehicle.

All of this argument is about wanting to be able to call small electric motorcycles "bicycles", and sidestep sane restrictions on motor vehicles.

 

[furcifer]

They seem to want to limit speed by limiting motor power. Nobody seems to do that with automobiles. Why should it be done with ebikes?

They've been limiting displacement on low speed vehicles for 50 years. Watts seem to be the extension of that.

It's still weird how they strictly regulate low speed vehicles, while they allow +500hp vehicles that basically violate "speed limits" by their very existence.

Very few people actually "need" more than 100hp or to go more than 80mph.