Jay Turberville

You didn't do yourself any favors by suggesting a rear wheel was a fan. That said, many of you points have some validity - even if they are, IMO, a bit exaggerated. Here's a nice article from Grin Electronics that explains in a pretty reasonable way the problems with "motor" ratings. It is also worth noting that power input to a motor is not the same as power output - especially with hub motors since efficiency can easily range from 0-80%. Sending 1000 watts to a direct drive hub motor means that in use it would be very unusual for that motor to ever output more than 750 watts.

https://ebikes.ca/learn/power-ratings.html

E-bike regulations in the U.K. do seem silly to me. And frankly, I suspect that the law makers there really don't care much about the issue. The same is true in the U.S., but we just happened to have a bike manufacturers advocacy group that managed to be effective (mostly because most law makers here don't really care much about the issue) I see two reasonable choices. 1) Be an outlaw and skirt the law riding a safe, practical, but technically illegal ebike. 2) Advocate for law changes (posting here is unlikely to help much). These choices are not exclusive of each other.

Shadco 

Easy solution.

Motorized scooter, use the roads, problem solved.

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Bonzo Banana

I really don't see how the spinning spokes don't have a cooling effect on the motor. We all know that the spokes are a major cause of drag, the more you have spinning the more drag you have. It's creating a huge amount of air turbulance and the spokes are connected to the hub motor itself. How can it have anything but a cooling effect on the hub motor? I realise devices like hub sinks are more effective but even those rely on the air turbulance caused by the rotating spokes. You are basically forcing hot air away from the area, its creating far faster air flow. I didn't even realise this was in the debatable category as I'm sure I've seen it featured as a selling point on hub motors and just seems so obvious. That's why ferrofluid is beneficial for direct drive hub motors as it allows better heat transfer from the core of the hub motor to the outer hub shell where cooling is so effective.

Alan K

Define major!

Spokes are not directing the air towards the motor in the center of the wheel. One way the spokes will help dissipate some heat is through “conduction”. The flange of hub will transfer a small amount of heat to each spoke. Since the cross-section of each spoke is very small, it will only be a very small amount of heat. I’m not sure how efficient are the hub motors but I will be very surprised if they are more than 70% efficient, which would mean that about 30% of the 500W or 1000W (as the case may be) are wasted in generating heat. And that is considerable amount of heat to be dissipated by spokes you fantasize as a fan blowing on the motor. Bulk of it is radiated off the large housing of the motor (hub).

I don’t think you are making much sense… but may be I’m missing something.

Jay Turberville

Let's put the goalposts back where they started. You said they had the cooling effect of a fan, suggesting that the cooling effect was significant. Well, it isn't. There isn't enough contact area between the spokes and the motor case to conduct the heat away in any significant amount. And while fans are designed specifically to move a lot of air, bicycle spokes are generally designed to avoid doing so. Spin a bike wheel really fast. It doesn't move much air. It certainly doesn't move much air toward or over the hub motor. The bike's forward motion, however does.
And I guess that's the point. Even though you have some concepts down pretty well, you miss the boat on others. Hub sinks are effective because they provide a very large area of contact to the hot motor case and present much more surface area to moving air than does the case by itself. The greater surface area allows the hub sink to transfer heat to the air more efficiently. Ideally they wouldn't create a lot of turbulence but would encourage high volumes of smooth airflow instead. The air movement that is important to the hub motor cooling has very little to do with the spokes. It is mostly due to the motion of air across the hub case as the bike moves forward.

Right. It is the hub shell shedding heat to the air passing by that matters. And ferrofluid makes that more efficient for exactly the reason you state. Like I said, you do seem to have a good handle on some of these issues. But the spokes aren't doing much to help cool that hub motor. And they aren't acting like a fan.

tallbikeman

As you properly pointed out motors are generally built to their end output requirements. There may be motors that are built to a spectrum of output watts which means the motor is built to the largest output expected but used at a lower wattage. This derating would produce longer lived motors at lower wattage usage. I highly doubt that derated motors are being produced. Every ounce of metal be it copper, steel or some other costs money and this industry is about profits. That said speed should and is being used to regulate e-bikes here in California. They also mention wattage ratings with 750 watts being a more or less top motor rating for street legal use. I run a RAD City with a 750 watt hub motor which is regulated by its controller to 20mph. 20mph is way too fast for sidewalk operation in most situations but is fine for street use. I use the first level of PAS(power assist) at 54 watts which is the least amount of assist and manage 14mph all day on heavy duty 26"x2.25" MTB tires. I believe that being a very conservative user of the streets is always warranted. Big steel fenders always, always, always have the right of way no matter how mad you are at them. One can't keep up a high level of mad while resting in a coffin. I love my e-bike and ride it almost every day with my wife riding hers. She had stopped riding because of aging body components. These e-bikes have gotten us on the road for the last 3 years and it has been a very happy experience.

tallbikeman

Amen to emergency throttle usage. I also will use throttle getting started at intersections. Very good points.

Jay Turberville

This article should give you some insight into hub motor power ratings. I'm not sure how it relates to mid drive motors, but I'd assume that there are similar issues and amounts of leeway.

https://ebikes.ca/learn/power-ratings.html

tallbikeman

Very interesting article. Heat is always the enemy for electrical equipment. I worked in a heavy industrial environment and whenever we smoked something we would say we let out the factory installed smoke magic that made whatever work electrically. Thanks for the heads up to this article. Shows the difficulty in rating continuously variable speed, continuously variable load electrical motors for continuous duty.

2old

I didn't wade through the article (will someday), but think a reasonable starting point would be controller amps X battery voltage for rating power. Also, the only times any of the DD or geared hub or mid motors have ever been hot to the point that I let them cool for a minute or two was on 100 degree days when I was ascending a steep hill. This probably occurred fewer than five times in about eight years.

p.murray@rogers

At first glance I thought it was the Ontario Provincial Police's new paddy wagons.

Jay Turberville

If you mean the continuous rating and not the peak rating, then that probably yields bike performance not overly beyond what the typical person who is told "750 watts means one horsepower" expects. Why?

Most controllers will ouptut peak power of about twice the rated power and most motors have a peak efficiency of about 80%. When pushed hard, few hub motors ever actually operate at that 80% level. They will more commonly be in the neighborhood of 70% efficiency and when the motor does actually output more than 750 watts, it generally either won't be for very long (peak 28 mph speed reached and throttle cuts out) or even result in very high speeds (going uphill can cause prolonged high outputs).

Anybody curious about such things can play around with variables on the Grin Motor Simulator.
https://ebikes.ca/tools/simulator.html

linberl

Fortunately you don't make the laws.

Shadco 

Fortunately around here motorized scooters are restricted to roads.




They are also much more suited for purpose.

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Rick_D

Similar.
Motor-driven cycles.

• A motor-driven cycle has 2-3 wheels and an engine size smaller than 149 cc.
• You must register a motor-driven cycle, and you must have a motorcycle license (M1) to drive one.

Mopeds

• Also known as a motorized bicycle, a moped has 2-3 wheels and an electric motor with an automatic transmission that produces less than 4 gross brake horsepower.
• Some mopeds have pedals so you can ride them when the motor is off.
• You must have a motorcycle license (M1 or M2) to drive a moped.
• You must be at least 16 years old or older to drive a moped, and you must wear a helmet while you ride.
• You do not need insurance to register a moped, but you do need special license plates and an identification card, along with a one-time $23 registration fee.

You do not have to renew your moped registration in the same way as you register other vehicles.
Scooters

• A motorized scooter has 2 wheels, a motor, handlebars, and a floorboard that you can stand on while riding it.
• You can only drive motorized scooters on a bicycle path, trail, or bikeway, not on a sidewalk, and you cannot exceed a speed of 15 mph.
• You do not need to register motorized scooters.
• You can drive a motorized scooter with any class driver’s license.

IDK where all the wacky things fit, like electric skateboards and one-wheelers, some of which seem to go 40 mph and are piloted by dudes in full-face moto helmets.

Speaking of scooters:
Reminds me a little of Uber dumping Jump bikes and scooters during the pandemic. Here, Lime picked them up but they're less common than pre-2020.

linberl

Glad I don't live near you and that I know the difference between pedal assist ebikes and motor scooters. Don't bother replying as I've blocked you.

tds101 

I don't really think that you understand the types of "scooters" most here are referring to are actually electric bikes (and also escooters, of which I'm fond of). This picture is of an electric moped, as it has no pedals. This just shows how misinformed the public really is when discussing these things. You're clueless...

unterhausen

there was a time when it was common for scooters like that to have pedals that you could take off and stow in a case. I even saw a teenager pedaling up a big hill near here on one. Regretting their life choices, no doubt. I recall Canada cracking down on them, no removable cranks. Which is a good rule.

As far as the line goes, I'm not sure this subforum should be about anything that doesn't fit in the class I,II,III system. If we held to that, then it would be a lot easier to police the lost roadies that stumble in here.

Shadco 

Why does an “E” Scooter have a muffler?

This is the type of scooter I was referring to in my op.

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Shadco 

Ouch, not sure I will ever recover.

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Jay Turberville

That system is not universal. So that seems to limiting to me.

veganbikes

Please do not disparage the Irish. Paddy is a disparaging term and does not need to be used to describe police wagons.

jon c. 

The pictured vehicle certainly appears to be a gas powered motor scooter.

A moped has peddles according to the classical definition. Thus the "ped" suffix. The mopeds of my youth were gas powered.

tds101 

The fact that I made the unfortunate mistake of missing the muffler on this scooter is irrelevant. The other fact that it was used as an example proves the stupidity of the posting of it as an example for the discussion taking place. Glad to see the ignorance displayed so visually. The people here are specifically discussing bikes, so gas powered vehicles are a different topic completely. A gas powered "moped" requires a driver's license and registration in most states. An Ebike is completely different.
Mopeds are still gas powered vehicles. Most here are specifically referencing "e" bikes. This was posted just for the "troll" effect.

2old

The best thing is to report individual(s) who have no knowledge of e bikes or the laws concerning them. I know that some of the excellent mods we've had in the past will warn them, then ban if they persist. It's not worth arguing with them because IMO that's the response they're seeking. Most individuals who post here know there is a Class system in about 75% of the states which define Class 1, 2 & 3 e bikes as bicycles with the same rights and responsibilities as bicycles unless they're prohibited specifically in certain towns, counties or wherever. Some states have even less restrictive laws for them. BTW, Siu Blue Wind is an administrator who seems to have watched this forum at times and has represented us perfectly.