Is 250w enough power for modest speed up steep hills

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

Post by Cugel »

richtea99 wrote: 30 May 2022, 7:05pm
imk123 wrote: 30 May 2022, 5:53pm Why do " ‘cyclists’ out for exercise." need Ebikes?
Why do " ‘cyclists’ out for exercise." need gears? What's wrong with a singlespeed. Are you weak or something?

Next random question please. :D
Why the two wheels!? One's enough, surely? Also, those saddles are for softies, eh? And the handlebars, yes.

Cugel

PS And do cyclist really need clothes if they're trying hard, even if it is snowing?
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hemo
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Re: Is 250w enough power for modest speed up steep hills

Post by hemo »

stodd wrote: 30 May 2022, 12:40pm
hemo wrote: 30 May 2022, 11:19am Woosh fo example use 9 or 10a controllers for there bikes with 250w hubs.
Are you sure on that?
Their kits mostly quote 17amps (Limit current (max. continuous)). Even 18a on the fairly basic XF07.
I can't see the equivalent specified on the bikes.
Yes woosh do use 17 - 20a controllers but that isn't there true rating but th max rating, as I mentioned most ebike controllers are rated typically 7a for a lot of 250w systems but will operate at double, hence why I said woosh use 9/10a models as they will operate at about double. My kt's are 12a but one can push 25a as the this is stated on them +/- 1a.
mattsccm
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Re: Is 250w enough power for modest speed up steep hills

Post by mattsccm »

As usual we are splitting the thread. Some people are answering the question ad some are going off on the old ebike tangent. An ebike doesn't need enough power to go up hill at speed . It needs enough power to get the rider to the top at the speed of a normal, not especially fit non ebike equiped rider. So, as in my case yesterday, on the local 25% hill, about 4mph.
We are talking bikes with a bit of boost for the less fit here, not a new form of motorised transport.
stodd
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Re: Is 250w enough power for modest speed up steep hills

Post by stodd »

mattsccm wrote: 30 May 2022, 9:05pm It needs enough power to get the rider to the top at the speed of a normal, not especially fit non ebike equiped rider. So, as in my case yesterday, on the local 25% hill, about 4mph.
We are talking bikes with a bit of boost for the less fit here, not a new form of motorised transport.
Absolutely.

As a matter of interest, do you have a hub drive or a crank drive motor? Most hub drives are getting really inefficient by the time you slow to 4mph. eg our XF07 is down to just over 40% efficient at 6mph and only just over 30% at 4mph. (<<< edit there, I mistyped 40% originally)

https://ebikes.ca/tools/simulator.html? ... h&grade=13
Last edited by stodd on 31 May 2022, 2:58pm, edited 1 time in total.
imk123
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Re: Is 250w enough power for modest speed up steep hills

Post by imk123 »

stodd wrote: 31 May 2022, 9:06am
mattsccm wrote: 30 May 2022, 9:05pm It needs enough power to get the rider to the top at the speed of a normal, not especially fit non ebike equiped rider. So, as in my case yesterday, on the local 25% hill, about 4mph.
We are talking bikes with a bit of boost for the less fit here, not a new form of motorised transport.
Absolutely.

As a matter of interest, do you have a hub drive or a crank drive motor? Most hub drives are getting really inefficient by the time you slow to 4mph. eg our XF07 is down to just over 40% efficient at 6mph and only just over 40% at 4mph.

https://ebikes.ca/tools/simulator.html? ... h&grade=13
Rear dropout is 130mm on this little Dahon and all the rear hubs i have found seem to be 135mm
So after much reading i think mid drive is the best option.
I was hoping the Tongsheng TSDZ2 would fit but the seat down tube would interfere with the fixing :-(
Hence at this time I think the Bafang looks the only option, unless there are other solution i have not found yet.
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Cugel
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Re: Is 250w enough power for modest speed up steep hills

Post by Cugel »

stodd wrote: 31 May 2022, 9:06am
mattsccm wrote: 30 May 2022, 9:05pm It needs enough power to get the rider to the top at the speed of a normal, not especially fit non ebike equiped rider. So, as in my case yesterday, on the local 25% hill, about 4mph.
We are talking bikes with a bit of boost for the less fit here, not a new form of motorised transport.
Absolutely.

As a matter of interest, do you have a hub drive or a crank drive motor? Most hub drives are getting really inefficient by the time you slow to 4mph. eg our XF07 is down to just over 40% efficient at 6mph and only just over 40% at 4mph.

https://ebikes.ca/tools/simulator.html? ... h&grade=13
Now that is a highly relevant statistic! It suggests that a mid-motor drive through the gears is going to remain much more efficient (assuming you have low enough gears) at very slow or just-rideable speeds. For some, that would be a primary consideration when deciding on which type of motor system to go for.

Of course, I myself always ride at 37mph so don't need the motor. :-)

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

Post by the snail »

mattsccm wrote: 30 May 2022, 9:05pm ....We are talking bikes with a bit of boost for the less fit here, not a new form of motorised transport.
I disagree, ebikes are not just for those with health/fitness issues, and they are indeed a new form of transport. A lot of people are using them for commuting, because for example they aren't sweaty, but still getting some exercise - it just gives people another option.
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Cugel
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Re: Is 250w enough power for modest speed up steep hills

Post by Cugel »

the snail wrote: 2 Jun 2022, 9:26pm
mattsccm wrote: 30 May 2022, 9:05pm ....We are talking bikes with a bit of boost for the less fit here, not a new form of motorised transport.
I disagree, ebikes are not just for those with health/fitness issues, and they are indeed a new form of transport. A lot of people are using them for commuting, because for example they aren't sweaty, but still getting some exercise - it just gives people another option.
Just so.

One of the "other options", I'm slowly discovering, is that you can ride an e-bike in hilly-windy locales and still output just as much thrust at the pedals yourself as you would on a non-e-bike. You just go faster in those difficult part of steep hill and strong headwind.

Now, purists (including me) might suggest that those who require the full cycling experience thing, of deepest and widest kind, should accept the lung-bursting, leg-sapping hills unassisted, as well as the misery of cycling 25 miles into a 15mph headwind with 25mph gusts. It builds character, see! Also, it's nice when it stops and you get the glow of accomplishment as well as endorphins.

Still, the e-bike allows you to do all that albeit in a shorter time. Of course, some will say that we should suffer the hard parts of a ride for as long as possible. I mean, some lads do that LEJOG thing in winter; or even 24 hour time trials! But that's just masochism, innit? They should see a trickcyclist, to have their self-punishing compulsions analysed away. :-)

Cugel, being seduced by a Fazua succubus.
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Carlton green
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Re: Is 250w enough power for modest speed up steep hills

Post by Carlton green »

the snail wrote: 2 Jun 2022, 9:26pm
mattsccm wrote: 30 May 2022, 9:05pm ....We are talking bikes with a bit of boost for the less fit here, not a new form of motorised transport.
I disagree, ebikes are not just for those with health/fitness issues, and they are indeed a new form of transport. A lot of people are using them for commuting, because for example they aren't sweaty, but still getting some exercise - it just gives people another option.

If ebikes give someone another option then isn’t that another form of transport, and as a motor is involved then it follows that that is a new form of motorised form of transport. That’s not to say that I’m against low powered ebikes, a bit of a boost for the less fit is very welcome. On the other hand faster and higher powered ebikes confuse; I suggest that they need to be recognised as mopeds and distinct from bicycles or else there will be cries demanding all types of restrictions on cyclists.
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.
Nearholmer
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Re: Is 250w enough power for modest speed up steep hills

Post by Nearholmer »

Yes, I agree that the distinction between ‘bikes with a bit of modest boost’ and ‘other things’ (mopeds to all intents and purposes) needs to be maintained, mainly because I’m borderline fanatical about maintaining shared-use paths, which are our primary way of getting about locally, as usable by all, and to preserve the tranquility of bridleways, towpaths etc.
saudidave
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Re: Is 250w enough power for modest speed up steep hills

Post by saudidave »

Carlton green wrote: 3 Jun 2022, 6:36pm
the snail wrote: 2 Jun 2022, 9:26pm
mattsccm wrote: 30 May 2022, 9:05pm ....We are talking bikes with a bit of boost for the less fit here, not a new form of motorised transport.
I disagree, ebikes are not just for those with health/fitness issues, and they are indeed a new form of transport. A lot of people are using them for commuting, because for example they aren't sweaty, but still getting some exercise - it just gives people another option.

If ebikes give someone another option then isn’t that another form of transport, and as a motor is involved then it follows that that is a new form of motorised form of transport. That’s not to say that I’m against low powered ebikes, a bit of a boost for the less fit is very welcome. On the other hand faster and higher powered ebikes confuse; I suggest that they need to be recognised as mopeds and distinct from bicycles or else there will be cries demanding all types of restrictions on cyclists.
Carlton, such machines exist and they are called "Speed Pedelecs". Essentially they are ebikes that are unrestricted for road use and as such they require Tax, insurance, registration an M.O.T where apropriate and a licenced rider. Moped driving licence. Essentially they are mopeds as such and to the best of my knowledge are only marketed comerciallly in the UK by CUBE at present, but there may be others.
Carlton green
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Re: Is 250w enough power for modest speed up steep hills

Post by Carlton green »

saudidave wrote: 3 Jun 2022, 8:52pm
Carlton green wrote: 3 Jun 2022, 6:36pm
the snail wrote: 2 Jun 2022, 9:26pm

I disagree, ebikes are not just for those with health/fitness issues, and they are indeed a new form of transport. A lot of people are using them for commuting, because for example they aren't sweaty, but still getting some exercise - it just gives people another option.

If ebikes give someone another option then isn’t that another form of transport, and as a motor is involved then it follows that that is a new form of motorised form of transport. That’s not to say that I’m against low powered ebikes, a bit of a boost for the less fit is very welcome. On the other hand faster and higher powered ebikes confuse; I suggest that they need to be recognised as mopeds and distinct from bicycles or else there will be cries demanding all types of restrictions on cyclists.
Carlton, such machines exist and they are called "Speed Pedelecs". Essentially they are ebikes that are unrestricted for road use and as such they require Tax, insurance, registration an M.O.T where apropriate and a licenced rider. Moped driving licence. Essentially they are mopeds as such and to the best of my knowledge are only marketed comerciallly in the UK by CUBE at present, but there may be others.
Thanks for that clarification. I worry about the grey area in between clear mopeds and those trying to get away with having a fast bike that escapes the moped category. With ebikes a bit of help up the hill and maybe into a strong head wind is, to my rough judgement, enough to enable someone to remain cycling and no more than that. What counts as a bit of help? Well to my mind a constant limit of 300 watt of electrical power from the battery would be a good start point with motor gearing sufficiently low to stop speed falling much below say 10 kph. So peak mechanical power of say 250 watt is delivered at quite a low road speed and there isn’t much power difference between the boost given by the motor and what a reasonably fit ‘normal’ person would likely produce; the effect of the electrical boost being to assisted the old rider with the equivalent of some younger legs so he or she doesn’t have to either give up cycling or walk most 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.
PH
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Re: Is 250w enough power for modest speed up steep hills

Post by PH »

saudidave wrote: 3 Jun 2022, 8:52pm Carlton, such machines exist and they are called "Speed Pedelecs". Essentially they are ebikes that are unrestricted for road use and as such they require Tax, insurance, registration an M.O.T where apropriate and a licenced rider. Moped driving licence. Essentially they are mopeds as such and to the best of my knowledge are only marketed comerciallly in the UK by CUBE at present, but there may be others.
They're not unrestricted, they have different restrictions, I think the top speed is 45kph. And yes, there are others marketing them, see my earlier post in this thread for an example.
Airsporter1st
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Re: Is 250w enough power for modest speed up steep hills

Post by Airsporter1st »

I use electric assist on my Orbea Vibe around 14% of my ride. As a result of having an assisted bike, I am routinely covering around 3 times the distance I used to on a conventional pusher, so I’m actually getting at least twice the exercise as a result of using an ebike.
Nearholmer
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Re: Is 250w enough power for modest speed up steep hills

Post by Nearholmer »

Assuming that the 14% is devoted to the challenging bits of the route, you will be getting more low to medium intensity exercise, and less high intensity exercise. I’m no sports physiologist, but I understand both to be of value in different ways, so you are losing something, while gaining something else.
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