No, not the speed limit on the road; the one that says if the bike can go over a specific speed, it’s a motorcycle. In Oregon here, I understand that limit is 21 mph. No doubt it may vary by jurisdiction.
Not too long ago, someone introduced an ebike that had no traditional bike drive chain. The ebike was propelled entirely by the motor. Pedalling just ran a generator to recharge the battery. So no matter how hard you pedalled, you couldn’t go faster than whatever that ebike limit was where they were selling it. I can’t remember what that was, but it wasn’t very fast. Something like 20 km/hr (the market was in the EU.)
But that was a special case. How is the ebike limit enforced on other ebikes? Does type of ebike make a difference? I don’t ride an ebike but I know that some just assist pedalling, while others will go without pedalling, but you can pedal to make it go faster. What do they do when you exceed the ebike limit?
The e-bike controller is set with a speed limiter, such that the bike won’t exceed the legal maximum in the country in which it was sold. I bought one like that last year. I forget the exact limit, but I know it is lower here in Canada than in the US. So, the bike is physically capable of going faster, but the computer won’t let you do that.
ETA: Addressing, “What do they do when you exceed the ebike limit?”
If you can pedal well enough that you exceed the upper speed limit, then you’re just like a regular bike. The pedal assist system won’t add any extra help at that point. It will only kick in again if you drop below the limit.
In most jurisdictions your allowed 250w motor and their generally programmed to travel up the 25km/h without peddling, without peddling the motor should cut out above 25km/h. Exceed these parameters in my part of the world and your riding a motorcycle and can be fined according, this can include no licence, rego or insurance, unlikely but it would really hurt the hip pocket.
I could see defining a motorcycle for legal purposes as a bike that goes over a certain speed, whether it has a motor or not. But it doesn’t make sense to me that a bike with a motor counts as a motorcycle if the motor isn’t actually doing anything.
Now it would make sense to treat it like you were speeding.
These rules only apply to bikes that have motors. If you’re on a traditional pedal-powered bike, you’re free to go as fast as you’re physically capable of, without being defined as a motorcycle.
If the police suspect you’re using a bike capable of exceeding the allowed speed limits, they could check the controller. They’re largely standard across manufacturers, and it’s not difficult to put the controller in the mode that lets you check all the settings. So if you’re using a US bike in Canada, say, you can run into trouble if you attract attention.
As I said, my memory was likely wrong and it looks like it’s 25 km/hr. That’s not very fast; just about any cyclist who’s in even halfway decent shape should be able to cycle faster than that.
The limit here in Oregon (and this could be different in other states) is 21 mph (just under 34 km/hr). A decent cyclist should be able to exceed that, too. Having to do it on an ebike, which is heavier (battery and motor), will make it more difficult, but still doable. Personally, I’d rather not have the extra weight slowing me down.
Many many years ago I had a moped; at the time Ontario limited them to 49cc and 30mph/50kph. I got pulled over by the police one night doing 36mph. They laughed and let me go once they were satisfied the bike wasn’t stolen. Basically, the design of the motor and the belt-drive clutch pretty much limited it to its top speed, but by leaning down almost flat on the handlebars, could reduce wind resistance enough to get a bit better speed, and if you had a tailwind, bonus.
I imagine the same can be done with electric bikes. You have a motor HP, you have a gear ratio, you have a maximum rider weight(recommended) and even without governor, the engine will only perform so well. Electronic limiting is just gravy.
I recall an item from long ago in Scentific American about cycling speeds. As you approach 30mph (50kph) the dominant limitation is wind resistance. This is why human powered bikes cannot get much fast on a flat road; apparently with a streamlined cowling, up to 40mph is possible (A bare bike and rider are not too aerodynamically slick). They had experiments where cyclists performed in a bubble suspended behind a truck, and with no wind resistance 60mph/100kph or more was possible.
So even without governing, odds are the engine power is a limiting factor.
The record for that kind of riding is much higher. Denise Mueller-Korenek set that record in 2018 at a speed of 183.93 mph (296 km/h) behind a modified drag racer at the Bonneville Salt Flats. Yes, a woman holds the outright world record, not just the women’s record, for this.
Not for the wimpy European limit of 25 km/h. Those bikes could easily exceed that speed.
That was a formidable achievement by Denise Mueller-Korenek, the Wikipedia link says the drag racer “reduces” the resistance but the fact is that shield creates a vacuum as it cuts through the air which pulls her along, but an amazing feat of strength and courage whatever
The article I remember it was a big plastic bubble that rode about two inches or so above the ground (on the Utah Salt Flats, IIRC), so no vacuum sucking the rider along, it would be more like riding a stationary bike.
That record was set in 2018 by the article. The article I remember was about aerodynamic drag research on bikes, from late 80’s or early 90’s. Basically it was using a full surround plastic dome about 10 or 15 feet long hung behind a truck, and standard racing bikes.
Things must vary around the world but the pedal-assist is key to the definition of an e-bike here in the UK - pedelec is the official term. If the bike goes without pedalling, ie it has a throttle of some sort, then it’s not an e-bike. It would be some sort of e-moped and not road legal without license, registration, insurance, MOT etc. Maybe not road legal ever as I doubt you could get an MOT on such a machine.
The speed limit is restricted to 25kmh as said. This is very easy to bypass by tinkering with the motor, and many people do - not all of them dickheads, either. 25kmh is right around the comfy commuting speed for a lot of people on clear road, and if you want to go a bit above then the assist cutting in and out is (apparently) really aggravating.
(MOT is a mandatory, yearly inspection certificate of road-worthiness for all vehicles older than 3 years in the UK)