Is 250w enough power for modest speed up steep hills

[thirdcrank]

In the unlikely event that the government were to introduce a keep-up-with-your-mates classification, I wonder how it might work. It seems unlikely that there would be personalised classifications eg ex 1 cat rider allowed more assistance than a 3 cat so that would seem to imply that ebikes in general should be powerful enough to allow any rider to keep up with any other who is riding without assistance.

[peterb]

I'm not suggesting personal limits, but limits by category. A 15.5 mph assistance limit was deemed to be appropriate for utility-bikes and was subsequently adopted to cover all other classes of bikes as they were introduced. In my opinion (and I accept not that of the majority of those posting), a slightly higher assistance limit for leisure bikes may well be appropriate. The problem of idiots on bikes riding dangerously on shared use paths is irrelevant as such anti-social behaviour will occur, limits or no limits.

[Carlton green]

I'm not suggesting personal limits, but limits by category. A 15.5 mph assistance limit was deemed to be appropriate for utility-bikes and was subsequently adopted to cover all other classes of bikes as they were introduced. In my opinion (and I accept not that of the majority of those posting), a slightly higher assistance limit for leisure bikes may well be appropriate. The problem of idiots on bikes riding dangerously on shared use paths is irrelevant as such anti-social behaviour will occur, limits or no limits.

CJ countered that stance on idiots in one of his - rather good - earlier posts.

There is a similar argument in the USA that it’s OK for everyone to have firearms. In reality the best way to stop idiots from doing things is to take away their toys and generally make it harder and tiresome for then to behave badly; that might not eliminate antisocial behaviours but it certainly curbs them.

250 Watt and 25 KPM is sufficient to help folk get about, those that want more have the moped option.

[PH]

I'm not suggesting personal limits, but limits by category. A 15.5 mph assistance limit was deemed to be appropriate for utility-bikes and was subsequently adopted to cover all other classes of bikes as they were introduced. In my opinion (and I accept not that of the majority of those posting), a slightly higher assistance limit for leisure bikes may well be appropriate.

How do you think that could work?

[peterb]

I'm not suggesting personal limits, but limits by category. A 15.5 mph assistance limit was deemed to be appropriate for utility-bikes and was subsequently adopted to cover all other classes of bikes as they were introduced. In my opinion (and I accept not that of the majority of those posting), a slightly higher assistance limit for leisure bikes may well be appropriate.

How do you think that could work?

The way it works at the moment - by the manufacturer adjusting software controlling the cutoff speed.
Anyway, I'm bored with the same old 'get a moped advice', so no more comment here from me. Happy cycling!

[Bonzo Banana]

So, given 250 Watts and an assisted speed limit of roughly 15 mph, what arrangement (some gearing, makes and models would be good) will make the best use of motor power and battery life?

Depends on the terrain you'll be riding on.
Rough, rocky, hilly areas and your motor will thank you for low gearing. In fact, that probably is correct for any sort of cycling as the motors perform best at higher rpm.
Where that gearing has a downside is when pedalling beyond the 15.5mph limit unless you like spinning.

One thing I have noticed since fitting my quite illegal 48v 750w motor though...
Detuning it to 240w (I don't need 750w as that's ridiculous) is giving me a brilliant battery life. Battery fully charged comes out at 50v. I've put 20 odd miles on it and the battery is still at 50v which is why I did it. Even with the 15.5mph limit set it's still illegal but that's a chance I'm willing to take for the range increase.
I used an online electric power calculator thingybob to work out that 48v X 5amp = 240w. If any leckie geniuses here could confirm that I'd be grateful.

Well as the motor takes more current it gets hotter so you have greater heat loss and with more power you typically ride faster so you have more wind resistance causing the motor to work harder. Also the equation between rider effort and motor effort swings to rider effort as you reduce the current going to the motor. In fact I saw this in a Grin video which I'll see if I can find the image they showed. It basically showed even with the motor being less efficient in theory (power in vs power out) it was more efficient in reality due to other factors. This is from a direct drive hub motor but the reality is the same for other motor systems as a generalisation.

[thirdcrank]

It wouldn't work because so many people would have reasons to up the power a bit more.

FWIW, bearing in mind the trouble the UCI seems to be forced to go to, to prevent electric doping in races, the technology must be available already to allow a club rider's bike to be enhanced (?) in a way that would evade the attention of the police - unless there were to be a bad crash.

[Vantage]

I seem to remember a case a number of years ago in the TDF where a bike check (I think) found the bike to have a battery installed within the seat tube powering a small motor within the bottom bracket. Not very powerful, but enough to give the rider an edge.

[CJ]

I seem to remember a case a number of years ago in the TDF where a bike check (I think) found the bike to have a battery installed within the seat tube powering a small motor within the bottom bracket. Not very powerful, but enough to give the rider an edge.

Off topic, but I think you'll find that most if not all bikes in the TDF have a battery installed within the seat-tube (or elsewhere) powering two small motors (or servos) within the gear mechanisms. Not very powerful, but enough to give the rider an edge.

To suggest that this borrowed energy does not give an edge is nonsensical. Nothing new goes onto a racing bike that does not in someway help the rider perfom better than before. So I don't think any stored energy device should be allowed by UCI - not unless the energy is topped up by the rider during the event.

This could very easily be done with existing technology. And if that small generator were to cause sufficient drag that no competitor wanted such improvements as electric shifting, power meters, race radios... then we would know for sure that all recent winners really were cheating!

[jois]

I'm not suggesting personal limits, but limits by category. A 15.5 mph assistance limit was deemed to be appropriate for utility-bikes and was subsequently adopted to cover all other classes of bikes as they were introduced. In my opinion (and I accept not that of the majority of those posting), a slightly higher assistance limit for leisure bikes may well be appropriate. The problem of idiots on bikes riding dangerously on shared use paths is irrelevant as such anti-social behaviour will occur, limits or no limits.

It does tend to limit the age range of the antisocial riders to about 35 and also removes a fair number of them who wouldn't actually power their own journey

Antisocial ebike riding seems to apply to a great many folk some what older than that .

As I doubt electric cars will be scalable to the general population who currently have a ICE By what every the current dead line actually is.then electric bikes of one form or another are possible the future of personal transport in the short to medium term, if they don't scrap the whole idea

In which case if there are going to be many millions of them, there needs to be a big rethink on policy

[harriedgary]

I think that cargo e-bikes - including tenbikes' log hauler - should come under the same regulatory regime as this new category of vehicle. They are a significantly heavier vehicle than even a loaded touring bike.

I just googled tenbikes log hauler and got this result.
And I totally agree these should be regulated, and shouldn't be allowed on cycle paths.

Maybe something else was been referred to...
I jumped in midway to this thread as I were looking for something specific.

[tenbikes]

^^^^^yeah, that's what I've got. You can see why I need a 1000w motor, yes?

[My average speed seems to be sub 8mph....]

[rjb]

I seem to remember a case a number of years ago in the TDF where a bike check (I think) found the bike to have a battery installed within the seat tube powering a small motor within the bottom bracket. Not very powerful, but enough to give the rider an edge.

I think this was a lady riding in a cyclo cross event who was powering up the climbs. Got caught and banned for life. Fabio Cancellara would carry an AA in his pocket to taunt the crowds when he won an event after being accused of having electric assist.

Here you go
https://www.cyclingnews.com/news/uci-co ... pionships/

[Vorpal]

I think that cargo e-bikes - including tenbikes' log hauler - should come under the same regulatory regime as this new category of vehicle. They are a significantly heavier vehicle than even a loaded touring bike.

I just googled tenbikes log hauler and got this result.
And I totally agree these should be regulated, and shouldn't be allowed on cycle paths.

He was referring to

Indeed.
My current e bike is for hauling loads off road. It needs to be more than 250w, but speed is irrelevant, in fact I have limited it down to 10mph because that's all I can manage safely off road with a load.
It sometimes gets defeated even with its generous power rating.

Think tractor v sports car. I have no need or interest in a sports car.

[harriedgary]

I'd been looking for electric trailers, which is how I jumped into that thread via search terms, wasn't sure if "tenbikes loghauler" was a legitimate make of cargo bike by some manufacturer so googled it hence the picture