Is 250w enough power for modest speed up steep hills

Electrically assisted bikes, trikes, etc. that are legal in the UK
peterb
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Re: Is 250w enough power for modest speed up steep hills

Post by peterb »

Carlton green wrote: 23 Sep 2022, 1:43pm A day or two ago CJ made what I thought to be three rather good posts, thank you Chris .. some really constructive posts from the Electrical Engineering chap in Milton Keynes too.

A point in one of them was basically that some folk are, or act like, idiots, and that only a lack of electric assisted power stops them doing stupid things or, in some cases, even more stupid things than they currently do. As such, and as in much of life, the majority of folk are limited by what the mindless or unthinking minority will do; in this case that results in limiting e-bike power and capping assist speed.

To be honest I think that 250 Watts sounds to be plenty to at least keep people mobile and active, and particularly so when transmitted to thrust at the wheel / road interface through appropriate gearing. An assisted speed cap doesn’t seem unreasonable to me, an an unassisted cyclist I just hope to average around 12 mph and the assisted speed cap is the right (top) side of that lowly figure.
The idiots are going to be idiots whatever they are riding - assisted or unassisted. You can ride an e-bike like an idiot under leg power alone. As a life-long road cyclist I was used to riding with a club group at well over 15mph unassisted, even in my late 60's - not averaging, but for long stretches when the road allowed. On the training nights on a racing circuit lapping at speeds of 25 mph plus were common, even with junior riders. I had to give up the unassisted bikes due to health issues. I still ride with a club, but my e-road bike assistance cuts out at 15.5mph, and I struggle to stay with a group on those long flats when the speed drifts up to 18+ mph. I doubt it will ever happen, but for those like me a separate e-road bike class with a cut off of 18mph would be helpful, at times. I don't want a free lunch, and try to ride the e-road bike much as I rode an unassisted bike, using as little assistance as possible.
thirdcrank
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Re: Is 250w enough power for modest speed up steep hills

Post by thirdcrank »

AIUI you can have an electrically-assisted bike which will go at pretty much any speed you like: it's called a motor bike and you need the appropriate driving licence and all the rest of the rigmarole to make it street-legal. The rules on pedal cycles have been altered to allow a certain level of electrical assistance which those responsible considered reasonable. If it's accepted that there has to be some sort of cut-off point then the one we are discussing seems fair enough. With most boundaries, somebody would like more latitude
peterb
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Re: Is 250w enough power for modest speed up steep hills

Post by peterb »

thirdcrank wrote: 23 Sep 2022, 3:22pm AIUI you can have an electrically-assisted bike which will go at pretty much any speed you like: it's called a motor bike and you need the appropriate driving licence and all the rest of the rigmarole to make it street-legal. The rules on pedal cycles have been altered to allow a certain level of electrical assistance which those responsible considered reasonable. If it's accepted that there has to be some sort of cut-off point then the one we are discussing seems fair enough. With most boundaries, somebody would like more latitude
As expected - the usual unsympathetic, unhelpful response. I hope you are never in the position I describe. I suppose your advice to me is shut up and make the best of it.
thirdcrank
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Re: Is 250w enough power for modest speed up steep hills

Post by thirdcrank »

FWIW, my health is much worse than you describe your own.
Carlton green
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Re: Is 250w enough power for modest speed up steep hills

Post by Carlton green »

peterb wrote: 23 Sep 2022, 3:31pm
thirdcrank wrote: 23 Sep 2022, 3:22pm AIUI you can have an electrically-assisted bike which will go at pretty much any speed you like: it's called a motor bike and you need the appropriate driving licence and all the rest of the rigmarole to make it street-legal. The rules on pedal cycles have been altered to allow a certain level of electrical assistance which those responsible considered reasonable. If it's accepted that there has to be some sort of cut-off point then the one we are discussing seems fair enough. With most boundaries, somebody would like more latitude
As expected - the usual unsympathetic, unhelpful response. I hope you are never in the position I describe. I suppose your advice to me is shut up and make the best of it.
I see both sides of the issue and as third crank basically says ‘you can’t please everyone’. My local club has some e-bikes in it and it also has some riders who aren’t all that fit too. Whether on e-bike due to diminished health or just not that fit and riding a traditional unassisted bike the accepted and unwritten rule is that nobody is left behind … clubs differ but I’d only want to be in one that wasn’t focused on a higher pace and was focussed on supporting every cyclist in the group. YMMV.

Is 250 Watt enough power for a modest speed up steep hills?
Don’t fret, it’s OK to: ride a simple old bike; ride slowly, walk, rest and admire the view; ride off-road; ride in your raincoat; ride by yourself; ride in the dark; and ride one hundred yards or one hundred miles. Your bike and your choices to suit you.
peterb
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Re: Is 250w enough power for modest speed up steep hills

Post by peterb »

Carlton green wrote: 23 Sep 2022, 4:05pm
I see both sides of the issue and as third crank basically says ‘you can’t please everyone’. My local club has some e-bikes in it and it also has some riders who aren’t all that fit too. Whether on e-bike due to diminished health or just not that fit and riding a traditional unassisted bike the accepted and unwritten rule is that nobody is left behind … clubs differ but I’d only want to be in one that wasn’t focused on a higher pace and was focussed on supporting every cyclist in the group. YMMV.

Is 250 Watt enough power for a modest speed up steep hills?
Depends on just how steep the hill is. 250w is certainly enough to stay with or even drop our group on most hills though anything over around 12% becomes very painful for me. Regarding club rides, it's a small club and I ride with the steady group, and it's not a problem except on those long flattish stretches where speed drifts up. It's very easy to drop off the back without anyone noticing! After all 18 mph is not very fast if you are riding with a group of regular cyclists. On the other hand I'm often one of the first at the top of the hill waiting so as to ensure no one's left behind. Not THE first, you will soon become unpopular if you regularly shoot off uphill!
Last edited by peterb on 23 Sep 2022, 4:54pm, edited 1 time in total.
peterb
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Re: Is 250w enough power for modest speed up steep hills

Post by peterb »

thirdcrank wrote: 23 Sep 2022, 3:57pm FWIW, my health is much worse than you describe your own.
You have my sympathy, but I wouldn't bet on it.
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Cugel
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Re: Is 250w enough power for modest speed up steep hills

Post by Cugel »

thirdcrank wrote: 23 Sep 2022, 3:22pm AIUI you can have an electrically-assisted bike which will go at pretty much any speed you like: it's called a motor bike and you need the appropriate driving licence and all the rest of the rigmarole to make it street-legal. The rules on pedal cycles have been altered to allow a certain level of electrical assistance which those responsible considered reasonable. If it's accepted that there has to be some sort of cut-off point then the one we are discussing seems fair enough. With most boundaries, somebody would like more latitude
The proposal I make (e-bikes all have a limiter on the motor such that motor + rider power never exceeds 250 watts in total) would actually make e-bikes less powerful overall compared to now. The e-bikes I have can all be set to give 250 watts of motor power which can be added to my own leg power. I can produce 200 watts for long periods and 300 watts for a minute or two. That gives the e-bike I'm on a potential total power of 450 - 550 watts! Only elite TdF riders can manage anything like that.

At present I can only get at the e-watts if I'm travelling at 25kph or less. So that 450-550 watts is only good for going up hills at unrealistic (for a averagely fit cyclist) speeds.

The current rules mean that, for example, a weaker club cyclist can drop everyone else on the climbs but will himself be dropped on the flat. PH doesn't think club cyclists count, of course, but I feel my alternative e-bike set of limitation rules (there's only that one - max total leg + motor power can never exceed 250 watts or thereabouts) provides a far better emulation of an unassisted bicycle than the rules that limit motor assistance speeds yet allow more overall power.

********************

All this stuff about not limiting e-bike assisted speeds because it'll cause more accidents on shared paths ..... Well, that really is a complete bit of whataboutery and also a large dish of red herring, eh?

************

Also, Bonzo will be pleased about my new rule as there's less risk of wearing out the transmission parts on the new less powerful but more useful e-bikes. :-)

Cugel
“Practical men who believe themselves to be quite exempt from any intellectual influence are usually the slaves of some defunct economist”.
John Maynard Keynes
Jdsk
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Re: Is 250w enough power for modest speed up steep hills

Post by Jdsk »

Cugel wrote: 23 Sep 2022, 5:22pm********************

All this stuff about not limiting e-bike assisted speeds because it'll cause more accidents on shared paths ..... Well, that really is a complete bit of whataboutery and also a large dish of red herring, eh?

************
What do you think would happen to the number of bikes travelling faster in that setting if the assisted speed limit were increased or removed? Fewer, the same, or more than if it weren't?

Thanks

Jonathan
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Cugel
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Re: Is 250w enough power for modest speed up steep hills

Post by Cugel »

Jdsk wrote: 23 Sep 2022, 5:28pm
Cugel wrote: 23 Sep 2022, 5:22pm********************

All this stuff about not limiting e-bike assisted speeds because it'll cause more accidents on shared paths ..... Well, that really is a complete bit of whataboutery and also a large dish of red herring, eh?

************
What do you think would happen to the number of bikes travelling faster in that setting if the assisted speed limit were increased or removed? Fewer, the same, or more than if it weren't?

Thanks

Jonathan
Assuming my e-bike new rule of max leg + motor power never rises above 250 watts? There'd be the same change that would occur if non e-bikes ridden by fast fools saw those fools getting a bit fitter .... as they do, you know.

Fast fools on bikes are a nuisance but a small one in the greater scheme of things. There are fast fools in cars. Should we limit the speeds of all cars (which, as you know, are motor-assisted) to 25kph because of the fast fools? I confess, I would quite like to do so. :-)

Cugel
“Practical men who believe themselves to be quite exempt from any intellectual influence are usually the slaves of some defunct economist”.
John Maynard Keynes
Jdsk
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Re: Is 250w enough power for modest speed up steep hills

Post by Jdsk »

Cugel wrote: 23 Sep 2022, 5:40pm
Jdsk wrote: 23 Sep 2022, 5:28pm
Cugel wrote: 23 Sep 2022, 5:22pm********************

All this stuff about not limiting e-bike assisted speeds because it'll cause more accidents on shared paths ..... Well, that really is a complete bit of whataboutery and also a large dish of red herring, eh?

************
What do you think would happen to the number of bikes travelling faster in that setting if the assisted speed limit were increased or removed? Fewer, the same, or more than if it weren't?
Assuming my e-bike new rule of max leg + motor power never rises above 250 watts? There'd be the same change that would occur if non e-bikes ridden by fast fools saw those fools getting a bit fitter .... as they do, you know.
...
Thanks

I think that there would be more going faster.

Jonathan
Jdsk
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Re: Is 250w enough power for modest speed up steep hills

Post by Jdsk »

Cugel wrote: 23 Sep 2022, 5:40pmin cars. Should we limit the speeds of all cars (which, as you know, are motor-assisted) to 25kph because of the fast fools? I confess, I would quite like to do so. :-)
That's an interesting response following your accusations of whataboutery upthread.

Jonathan
Jdsk
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Re: Is 250w enough power for modest speed up steep hills

Post by Jdsk »

thirdcrank wrote: 23 Sep 2022, 3:22pm AIUI you can have an electrically-assisted bike which will go at pretty much any speed you like: it's called a motor bike and you need the appropriate driving licence and all the rest of the rigmarole to make it street-legal. The rules on pedal cycles have been altered to allow a certain level of electrical assistance which those responsible considered reasonable. If it's accepted that there has to be some sort of cut-off point then the one we are discussing seems fair enough. With most boundaries, somebody would like more latitude
Yes.

In the real world laws and rules often include thresholds which are compromises and somewhat arbitrary. There's no way round this. Of course thresholds may need to change as something else changes or as more evidence becomes available.

Jonathan
Nearholmer
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Re: Is 250w enough power for modest speed up steep hills

Post by Nearholmer »

All this stuff about not limiting e-bike assisted speeds because it'll cause more accidents on shared paths ..... Well, that really is a complete bit of whataboutery and also a large dish of red herring, eh?
For clarity, which might, I’m not totally sure, have got lost here somewhere:

I’m advocating as loudly as is polite that the power/speed of EAPCs should continue to be limited, in order to protect shared-use of paths. Exactly what form of limit might be ideal can, of course, be debated, but provided it keeps the power unit “reasonably humanlike” in capacity, I will be happy.
Nearholmer
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Re: Is 250w enough power for modest speed up steep hills

Post by Nearholmer »

Is 250 Watt enough power for a modest speed up steep hills?
Yes.

And, if you have the fortitude to pick through all the posts in this thread, the maths that demonstrates the truth of that is in here.

The “keeping-up on club runs” thing intrigued me. Do not clubs have runs at different speed bands? Ours certainly does, the lowest speed band being 10-12mph, and the highest about 20mph I think (I’m not into group road runs, so don’t pay close attention to that side of things). If so, why not move down a band or two?
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