Geared hub motor hill climb performance

stolennomenclature
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Geared hub motor hill climb performance

Postby stolennomenclature » Sun May 01, 2011 9:54 am

Does anyone know of any resource on the web that provides some information that helps assess the hill climbing performance of a single speed geared hub motor? Just a ball park estimate is all I am after. I want to know whether a 200 watt hub motor geared for 25 kph will get me up a 3% grade for example, without pedaling. What speed should it be geared to to go up a 10% grade? 10kph?
There does not seem to be anything like this that I have found so far, and yet I would have thought this kind of info is crucial to assessing how useful a hub motor would be. I understand there are many variables which can alter the performance - bike/rider weight for example, but even figures for average weights would still be useful, together with a certain amount of extrapolation.
I live in an area surrounded by 6-8% grades, and have an injured knee which prevents vigorous pedaling. I want to know if it will do me any good to spend $600 on a 250 watt hub motor at all, and what speed I should have the motor geared for. At present I am assuming the motor would need to be geared for about 10kph to tackle the worst hills (if it can at all), but that would presumably limit speed on a flat.
Thanks.
:?

Joeblake
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Re: Geared hub motor hill climb performance

Postby Joeblake » Mon May 02, 2011 2:15 pm

If you are going to try and ride up a hill just on a small motor alone, make sure it has a good thermal protection system, otherwise you could wind up burning your motor out, particularly in hot weather.

My "small" trike (16" wheel) will climb Welshpool Road at about 4-5 km/h just on motor (200/400w) alone, but with moderately hard pedalling I can go up the same hill at 16 km/h, which is the maximum speed of the motor on the flat.

My "big" trike (26" wheel) uses the same motor but max's at about 24 km/h. Trying to climb the same hill on motor alone just flattens the battery and causes overheating. On one particularly hot day (40+ degrees C), even though I was pedalling fairly strongly the thermistor cut everything out. I managed to pedal to the top, but the motor took about 10 minutes to cool down sufficiently to give me assistance.

Joe
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Bertrand Russell

stolennomenclature
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Re: Geared hub motor hill climb performance

Postby stolennomenclature » Wed May 04, 2011 7:28 pm

Joeblake wrote:If you are going to try and ride up a hill just on a small motor alone, make sure it has a good thermal protection system, otherwise you could wind up burning your motor out, particularly in hot weather.

My "small" trike (16" wheel) will climb Welshpool Road at about 4-5 km/h just on motor (200/400w) alone, but with moderately hard pedalling I can go up the same hill at 16 km/h, which is the maximum speed of the motor on the flat.

My "big" trike (26" wheel) uses the same motor but max's at about 24 km/h. Trying to climb the same hill on motor alone just flattens the battery and causes overheating. On one particularly hot day (40+ degrees C), even though I was pedalling fairly strongly the thermistor cut everything out. I managed to pedal to the top, but the motor took about 10 minutes to cool down sufficiently to give me assistance.

Joe


I assume those trikes both use hub motors? Wow. Sounds pretty grim. I knew I would'nt be able to fly up the hill on a 200watt motor, but I had hoped at least I would get to the top without overheating!

What exactly do you mean by 200/400 watts? Are you saying its a 200 watt motor that you are overvolting to give 400watts, or that the motor is nominally 200 watts but delivers nearer 400?

Also, any idea how steep that hills is in % or degrees?

Thanks.

:roll: :roll:

Joeblake
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Re: Geared hub motor hill climb performance

Postby Joeblake » Thu May 05, 2011 12:23 am

The 200/400 watts is the continuous power/peak power.
(Cut and paste from the link below)

Note - the difference between Peak Power and Continuous Power:
This is sometimes a bit confusing, and to be honest I sometimes talk about peak and sometimes continuous when I’m talking about motors. Here’s the difference:

Peak Power: This is the maximum power the motor can happily produce - the motor will be able to put out this much power for a couple of minutes, but will then start to get warm so the controller will power down a bit. I usually talk about peak power when I’m talking about the high-power (non-legal) motors because you really want to know how much “grunt” it has, don’t you?

Continuous Power:
This is the power that the motor will happily put out for ever, without getting even slightly warm. Obviously this is lower than the Peak Power. I usually talk about this for the legal motors because this is what the law asks for - the continuous power not the peak power


This link has a fair bit of info.

http://www.kinetics.org.uk/html/the_motor.shtml

My trikes both use Heinzemann hub motors (same power) and it is limited to 198 rpm, hence the difference in performance based on wheel size.


The Gradient:

According to this link:

http://www.cycle2max.com/bike-hill-clim ... spx?id=283

Total Distance:
2.90km | 1.80mi

Starting Altitude:
80m | 262ft

Finishing Altitude:
261m | 856ft

Average Gradient: 6.3%

Elevation Gain:
181m | 594ft

Surface Type:
Smooth Bitumen / Asphalt


I continue climbing for a further 2 or so km, turning off into Gladys Road, heading towards the Ray Owen Sport Centre.

Joe
To acquire immunity to eloquence is of the utmost importance to the citizens of a democracy
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stolennomenclature
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Re: Geared hub motor hill climb performance

Postby stolennomenclature » Thu May 05, 2011 11:14 am

So your motors are basically "legal" motors, the type I want to use, but capable of bursts of double legal power. They are also Heinzman, which I have heard are if not the best then one of the best. The hills around my house are all between around 7-8%. So the overall picture is looking rather bleak for putting a 200 watt hub motor on my 26inch mountain bike, especially considering my inability to pedal strongly. I might as well save the dosh and walk the bike up the hills.

I must admit to be rather confused about the performance of ebikes. Most of the ebikes around seem to use hub motors and most people seem to be pleased with them, yet other info from you and some others tends to suggest they are not real good on hills. Logic seems to support this view. I can only conclude so far that the people who are happy with them are happy for one or more of the following reasons. 1/ They are in other countries which allow motors of 500watts and up and get up the hills by sheer brute force. 2/. They live in areas with few steep hills. 3/. They are fit people who augment the motor with vigorous pedaling. Unfortunately I cannot pedal vigorously, live in a very hilly area, and in Australia where the power limit is smaller than most in car stereo systems.

Looks like i'll have to wait till something else appears on the market.


:|

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Kalgrm
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Re: Geared hub motor hill climb performance

Postby Kalgrm » Thu May 05, 2011 10:24 pm

If you have concerns about what you would be capable of on a pedelec bike, why don't you take a few for test rides and see if they are suited to your needs? It's the only way you can find out if any of them fit the bill for your personal requirements.

cheers,
Graeme
Think outside the double triangle.
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cachexian
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Re: Geared hub motor hill climb performance

Postby cachexian » Fri May 06, 2011 6:58 am

Hi stolennomencalture,

Where do you live?

My commute to work (Manly from Haberfield) involves some quite steep hills. I don't know the grade but will look at that website that Joe found.

Anyway my ebike will take me up these hills without pedalling although slowly.

If you live in Sydney pm me. You'd be welcome to have a go on my bike around here.

Or you can try out bikes at some of the retailers.
Scott Sub 40 with 200W, 36v Ezee geared front hub motor
and...
Trek Madonne 3.1 driven by left leg and right leg

stolennomenclature
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Re: Geared hub motor hill climb performance

Postby stolennomenclature » Sat May 07, 2011 4:06 pm

As to trying out the bikes at a retailer, there are several reasons why i have not even attempted that course of action.

The most obvious one is that there are so few of them around, and none near me in Liverpool. Most ordinary bike shops look like they want to throw you out if you mention the dreaded "e" word.

One is that I am a crotchety, unlucky old man who has been disappointed by shops so many times in the past, that I always expect the worse. I expect to show up and find one of the following: they don't have ebikes in stock at the moment; yes we have one but someone went out on it this morning and has'nt come back yet; oh dear, the battery is flat - if you'd like to come back tomorrow we can charge it!; you want to try it on some hills? - you're out of luck - 'fraid it's all flat around here mate; it was a folding bike you wanted to try? oh - full size - sorry but the big one is being repaired; etc, etc. Likely if they did have one for me to try it would have been used and abused so badly that I would end up not liking it at all - you know, everything out of adjustment, dead battery, flat tires. Dear me, I am such a damned pessimist.

Thirdly even if I could find a bike shop with an ebike, they will never allow me enough time to properly evaluate the thing. One quick drive round the block probably will tell me next to nothing anyhow. Oh sure, it would be better than nothing I suppose, but perhaps not much better. If they did have a hill of some kind to climb up, chances they would not know how steep it was.

I shall probably do what I usually do - buy something and try it out at my leisure. In the meantime, I will do all the groundwork (as I am doing now on this forum) I can before I fork out the dosh.

cachexian
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Re: Geared hub motor hill climb performance

Postby cachexian » Sat May 07, 2011 10:30 pm

Hi Stolen,

Oh you are completely correct about most ebike retailers. I found the same problem...
"sorry but you can't take it around the block"
"oh I forgot to pump up the tyres"
"we can only order them in for you"
"try it around the carpark"
"you can get an idea by riding 100m up the footpath..."

BUT

I would like to put in a really good plug for Glowworm bicycles at Addison Rd Marrickville. Check out their website.

They will let you take out their bikes for as long as you like. If you really want to try them out properly, do what I did and hire one for 24 hours ($50 when I did it). I took two bikes home, charged the batteries fully, pumped up the tyres to the correct pressure and adjusted the seat correctly and then rode nearly 50km to Manly and back with my brother. Before I did the hire I took out both the Ezee bike and Whisper bikes for test rides around Marrickville (where there are some hills Newington Rd has a half decent hill)

On most of the ebikes that I tried, the power of the assist if governed by the speed that the pedals are rotating not by the force put into them. (Gazelle innergy is one notable exception to this)

I don't know just how bad your knee is but I would think that you could manage with a good pedalec ebike even with a 200w motor in Sydney. Perhaps even if you pedal a bit on the hills and rest on the flat.

I believe that it is not power but torque that gets you up hills and the torque is actually highest at the lower speeds of the electric motor. (I have an EVS 200W front hub internally geared motor...yeah I didn't buy my ebike kit from Glowworm but I do think that they have a great product).

On the issue of getting home if your knee played up, the Whisper bikes are pedalec but they do also have a throttle option. The throttle alone will only allow the bike to go slowly but it would get you home.

I actually don't really like the throttle control very much for me. I find that my hand gets a bit crampy from having to hold the throttle on all the time. I think that a good pedalec controller with a handy on/off switch would be really convenient for me. But then I don't have a bung knee and I pedal hard all the time on my ebike.

Glowworm is open Sundays too believe it or not!
Scott Sub 40 with 200W, 36v Ezee geared front hub motor
and...
Trek Madonne 3.1 driven by left leg and right leg

stolennomenclature
Posts: 31
Joined: Mon Nov 15, 2010 9:46 pm

Re: Geared hub motor hill climb performance

Postby stolennomenclature » Tue May 10, 2011 10:04 am

cachexian wrote:Hi Stolen,

Oh you are completely correct about most ebike retailers. I found the same problem...
"sorry but you can't take it around the block"
"oh I forgot to pump up the tyres"
"we can only order them in for you"
"try it around the carpark"
"you can get an idea by riding 100m up the footpath..."

BUT

I would like to put in a really good plug for Glowworm bicycles at Addison Rd Marrickville. Check out their website.

They will let you take out their bikes for as long as you like. If you really want to try them out properly, do what I did and hire one for 24 hours ($50 when I did it). I took two bikes home, charged the batteries fully, pumped up the tyres to the correct pressure and adjusted the seat correctly and then rode nearly 50km to Manly and back with my brother. Before I did the hire I took out both the Ezee bike and Whisper bikes for test rides around Marrickville (where there are some hills Newington Rd has a half decent hill)

On most of the ebikes that I tried, the power of the assist if governed by the speed that the pedals are rotating not by the force put into them. (Gazelle innergy is one notable exception to this)

I don't know just how bad your knee is but I would think that you could manage with a good pedalec ebike even with a 200w motor in Sydney. Perhaps even if you pedal a bit on the hills and rest on the flat.

I believe that it is not power but torque that gets you up hills and the torque is actually highest at the lower speeds of the electric motor. (I have an EVS 200W front hub internally geared motor...yeah I didn't buy my ebike kit from Glowworm but I do think that they have a great product).

On the issue of getting home if your knee played up, the Whisper bikes are pedalec but they do also have a throttle option. The throttle alone will only allow the bike to go slowly but it would get you home.

I actually don't really like the throttle control very much for me. I find that my hand gets a bit crampy from having to hold the throttle on all the time. I think that a good pedalec controller with a handy on/off switch would be really convenient for me. But then I don't have a bung knee and I pedal hard all the time on my ebike.

Glowworm is open Sundays too believe it or not!


I am just picking myself up off the floor - someone actually agreed with me on a forum post - my heads still spinning but beginning to clear. Sorry, it was the shock.

Good to hear about Glowworm - if I do decide to bite the bullet and visit a retailer I will give them a go. Thanks.

Also interesting to hear about your experience with Pedelec and the throttle. I did wonder about having to hold the throttle all the time, together with having all those controls on one handlebar (rear shift, front shift, throttle) and was trying to decide whether to go for a twist grip throttle and a lever shift or a twist shift and thumb throttle. I tend to agree with you about the advantage of pedelec as a throttle control most of the time, especially if one does not need to pedal hard but simply to make them turn. Hopefully one day when/if my knee recovers, I will never have to ride the bike when not pedaling (with the usual exceptions - coasting down hill, etc).

The kind of pedelc you refer to that uses a pedal torque sensor and provides motor power in relation to force being applied to the pedal, rather than simply speed of rotation is a kind of pedelec I would be least interested in. This kind would be real bad on hills. Its on hills when you need the most assistance, and you do not want to have to pedal hard in order to get the full assistance. This kind of pedelec is nice to have as an option, but not as the only method of control - at least not for me.

Thanks.

cachexian
Posts: 124
Joined: Sun Jul 25, 2010 10:39 pm

Re: Geared hub motor hill climb performance

Postby cachexian » Tue May 10, 2011 10:20 pm

Also, be aware that some brands of bike are pedalec bikes but you ALSO have to hold on the throttle the whole time. I've ridden twist grip (Ezee bike) and thumb throttle (mine) over long distances and I'd have to say that I prefer the thumb control.

I've reviewed my bike and the Ezee bike I rode in another post.

The whisper bikes had the best control system that I have trialled: a set and forget pedalec (set it for range or power with a variety of settings) with the option of no pedal throttle control (but the speed is VERY limited in the throttle only option). It would get you home if you had a knee explosion but you might have been able to hop faster. :D Actually, that's not fair. I don't know the exact speed but it just felt slow after 25kph.

The Whisper controller is programmable so it is possible that the pedalec can be turned off and the throttle used alone. You'd have to ask that of Glowworm.

I think that the Gazelle controller system is a really natural method of delivering power because you naturally put in more force into the pedals when you get to a hill. I can see why it wouldn't appeal to you with you knee.

Anyway, happy trialling. Good luck with the recovery.
Scott Sub 40 with 200W, 36v Ezee geared front hub motor
and...
Trek Madonne 3.1 driven by left leg and right leg

cachexian
Posts: 124
Joined: Sun Jul 25, 2010 10:39 pm

Re: Geared hub motor hill climb performance

Postby cachexian » Thu May 12, 2011 7:16 am

I tried riding up Sydney Rd, Manly this morning without pedalling to see how the 200W managed. It's a pretty steep hill (one of the steepest on my commute). The bike couldn't do it without pedalling. But with light pedalling (such as required to go about 16kph on flat) it went up the hill at a slow, but not wobbly 12kph.

At this time of year you need to worry more about frost bite than knee injuries if you're out on the road before 7am. Brrrr.

Cachexian.

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