Hill climbing
- Thread starter hoppy
- Start date
No chance, nothing near I'm afraid.
The most powerful legal climber without any pedalling is the eZee Quando, I have one. With my 11 stones (70 kilos) on board, and with a fully charged battery, it can just barely manage 14%, but the true limit without excess strain is about 13%.
Regularly checked as I live up a 14% hill.
Let me know your weight and I'll tell you how many watts you would need to climb 25% slowly on an average e-bike.
.
The most powerful legal climber without any pedalling is the eZee Quando, I have one. With my 11 stones (70 kilos) on board, and with a fully charged battery, it can just barely manage 14%, but the true limit without excess strain is about 13%.
Regularly checked as I live up a 14% hill.
Let me know your weight and I'll tell you how many watts you would need to climb 25% slowly on an average e-bike.
.
I have a road legal (road registered) 50 mph, 4kw electric scooter and that would not go up a 1 in 4 hill
If you want legal bike with a motor that runs through the gears then it will require physical input before it will work. I guess you could use a hub motor with reduced gearing but that's not going to manage anywhere near 15mph on the flat.
Can you really not do any pedalling or just think you can't, many people don't realise how easy these things make the hills. You'd probably need a Panasonic unit that works through the gears for 25% hills, though short ones will be OK with a hub motor if you are prepared to pedal hard for a bit. An electric scooter will struggle with hills that steep as will any 49cc petrol one.
I'm afraid not, the Quando I mentioned has internal gear reduction and has a nominal peak power of 720 watts, but in fact has been measured at 1000 watts gross peak power. I live in the North Downs and have a few 25% hills, one 33% hill and only yards from my home a stretch of 22.5%, so plenty of experience of what's possible. The 14% mentioned is a much as it can do unaided
Your 12 stones is just over 76 kilos, plus a typical e-bike weight of 24 kilos brings the gross climb weight to 100 kilos For climbing unaided a 25% hill at the lowest comfortable balance speed of 5 mph, that calculates to an absolute minimum of 570 watts of continuous power rating, a bit over double the legal figure.
However, that's still not enough, since you specified that the bike must achieve 15.5 mph easily, but the slowest a motor geared for that will give that maximum power is about 7 to 8 mph, depending on the motor design. Below that the power starts to tail off. To get that 570 watts continuous at a 5 mph climb speed, the continuous power rating of the proposed motor would have to at least 850 watts, over three times the legal limit.
The equation I've used for simplicity is:
Pu = 9.81MVgG
where Pu is the power needed in Watts, M is the total mass of the rider, bike and cargo expressed in kilograms, Vg is the ground speed in metres per second and G is the gradient expressed as a fraction that is the elevation changed over the distance travelled.
I've made a tiny addition to the watts to account for rolling resistance and frictions.
For steeper gradients such as 25%. G should really be changed for:
sine [tan-1(rise/run)]
but I haven't bothered since your requirement clearly cannot be met anyway.
.
I know of one not a million miles from where Flecc lives and only a short distance from member Fecn - Succombs Hill runs from Warlingham down to join the East Grinstead road (A22) and that's a 1 in 4 in places....
It's narrow, twisty, and busy as hell, and I wouldn't like to try it on anything less than a motorbike - in either direction.
Rog.
I remember a few years ago that one of the 50cycles guys took a Kalkhoff up the road to Alp d'Heuz without too many problems and I remember that being very steep. Maybe he pedalled a lot.
This probably won't be very helpful, however in my local town there is a mountain, and a Victorian tram that runs up the side at a 1 in 3 gradient.
I have cycled up this with my direct drive hub motor (Crystalyte 408 at 36v) at a steady 10 mph. Now I won't kid you, it took considerable effort and if I wasn't as fit as I am I would not have made it all the way. (Edit: I should probably make a video of this)
To put things into perspective, when I used to do this pre-electric, my speed would be way down at about 2-3 mph, and I'd be half dead at the top!
The point I am trying to make here, is that e-bikes are not mopeds. If you are prepared to put in your share of the effort, there really isn't much they can't tackle.
I have cycled up this with my direct drive hub motor (Crystalyte 408 at 36v) at a steady 10 mph. Now I won't kid you, it took considerable effort and if I wasn't as fit as I am I would not have made it all the way. (Edit: I should probably make a video of this)
To put things into perspective, when I used to do this pre-electric, my speed would be way down at about 2-3 mph, and I'd be half dead at the top!
The point I am trying to make here, is that e-bikes are not mopeds. If you are prepared to put in your share of the effort, there really isn't much they can't tackle.
Succombs Hill.... no problem I wasn't fast up there, but at least I wasn't sweating either. My agattu really can climb any hill.. albeit at 4.5mph... With my modified gearing, cruising speed on the flat is a healthy 17.5mph. You do need to pedal though as walk-along throttle has very limited power and speed available to it.
I wasn't fast up there, but at least I wasn't sweating either. My agattu really can climb any hill.. albeit at 4.5mph... With my modified gearing, cruising speed on the flat is a healthy 17.5mph. You do need to pedal though as walk-along throttle has very limited power and speed available to it.
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is that an 11 tooth sprocket or have you done something else ?Succombs Hill.... no problem
I replaced the Nexus7 hub gears with a Nuvinci CVT instead... 350% range instead of the old 244%. I have a 21tooth cog on the Nuvinci as I cared far more about hill climbing than top speed. I did try an 11tooth sprocket for a while which gave a top end assist speed of around 24mph but I changed back after a few weeks as it was very detremental to hill clikmbing.
You're a braver man than I. Too many incompetent drivers on there for my liking - I've seen some near misses due to stalled engines and missed gears going up, and going too fast on the way down - etc. Not much room for a cyclist either unless you ride on the pavement, and I seem to remember you don't GET a pavement all the way.Succombs Hill.... no problem
I'm sure there are e-bikes which will cope with it - presumably the Panasonic or similar drive-through-the gears systems will be a much better bet than hub motor bikes. I expect it would be quite a strain on the electrics and especially the battery no matter how hard you pedal on most bikes.
Hmmm - as one gets older one's instinct for self-preservation hopefully overtakes the effects of second childhood - as I passed my sell-by date a couple of weeks ago I'm sure that applies to me.
Rog.
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