Failed on my first big hill

[soundwave]

ill give it a go when its fully dry also cam peak is near the same and not to far away.

just need the rain to bugger off for a few weeks

 

[anotherkiwi]

I don't agree that a hub motor isn't as good a climber. I think it is a different kind of climber. Today I used granny gear on a few hills and as soon as I get Number Two (mid motor) finished I will be trying it out on that same road.

My hub motor is as legal as they come. As well as the sticker on the motor that says 250 W I have turned down the Amps on the controller "three whole points"* and top speed is set to 25 km/h + or - 5% (26 km/h).

After 2700 km I have learnt to be in the right gear at the right time much the same as on an un-powered bicycle. And I have climbed all but one "hill"** and that time I was probably at 3.5 grams of alcohol per liter of blood so I call a joker on that one. Its all about the gear ratios, on a hub motor as on a mid drive motor. If you don't have the right gearing you won't climb all of the hills you come across. Motor or not it is the same story just the hp is different.

* Rocky Horror Show reference, sorry!
** I won't go off into Cyrano de Bergerac citations but "a hill? no sir a wall!" etc. etc.

I thought the thread was lacking some comic relief, sorry!

 

[Jason Scott]

Before buying our bikes, my wife had a Raleigh Forge on loan for a week and found its hill climbing ability to be less than the Motus.

I got to try a Haibike SDuro (Yamaha motor) and I thought it had the edge on the Bosch although it seemed a little 'rougher'. I loved the styling and would've gone for it but primary use is commuting and therefore decided against it.

 

[(NoLongerRegistered#15675)]

By coincidence that's almost same as us..wife and I both borrowed Motus ; I tried Haibike sduro and hired both a Thron pro and Haibike xduro.
Had I been using for commuting/ road would have gone for Motus ( wife did) but offroad/ long long climbs steep climbs I bought sduro .
On road Motus more comfortable,changes gear slicker ( especially hub geared one,had panniers etc ..dont get me wrong Motus is great, for my use sduro is better.

Another kiwi
I did not say hub drives were not good climbers. Perhaps yourself and Eddie should re read my original post.
I said hub drives cant compete with cd on LIMITED current. ( which is exactly situation is on a long day out with a single battery, in this case a 400wh one)
Bulto Brinco is hub drive etc etc.

Hub drives have inherent problems ,exaggerated when combined with lower power.
It simply hasn't the torque to do job so a gearbox is essential to multiply torque for initial start.,hub then has to cope with that same gear ratio throughout bikes speed range....
If motor had sufficient torque for direct drive, problem solved, but then unsprung weight starts to be an issue.( which has implications for handling and broken spokes)

The elegant solution ( as you already know) is cd drive, which can get around torque issue with its own gearbox and then utilise bike,s gears for speed range, with added bonus of lowert unsprung weight, no problems changing wheels etc etc..

Yes cd is more expensive but it works and works well. That seems not to be case with all hub motors.

Soundwave
I,d love to try a 4000w hub drive..It would be fantastic for 6 minutes with a 400wh battery..????!!! I,ll stick to plodding along legally..but thanks.

 

[Deleted member 4366]

I said hub drives cant compete with cd on LIMITED current. ( which is exactly situation is on a long day out with a single battery, in this case a 400wh one)
Bulto Brinco is hub drive etc etc.

Hub drives have inherent problems ,exaggerated when combined with lower power.
It simply hasn't the torque to do job so a gearbox is essential to multiply torque for initial start.,hub then has to cope with that same gear ratio throughout bikes speed range....
If motor had sufficient torque for direct drive, problem solved, but then unsprung weight starts to be an issue.( which has implications for handling and broken spokes)

The elegant solution ( as you already know) is cd drive, which can get around torque issue with its own gearbox and then utilise bike,s gears for speed range, with added bonus of lowert unsprung weight, no problems changing wheels etc etc..

Yes cd is more expensive but it works and works well. That seems not to be case with all hub motors.

That's simply not true. Small, low power hub-motors can get you up any hills when they're designed for it. I guess you haven't tried a KTM Panasonic bike or a bike ith a Xiongda yet. When you have, come back and write with authority instead of spouting off your own made up theories.

OP's bike has a lot of good qualities, but unassisted hill-climbing is not one of them. He chose a bike with a torque senor, but his (presumed) unfit legs cannot sustain the force to get the maximum power from the system. It's the system design that's causing his problem, nothing to do with the motor. When his legs get a bit stronger from a bit of practice, he'll have no problem. At the moment, a system based on a cadence sensor would be better, but that will probably change with time.

 

[(NoLongerRegistered#15675)]

That's simply not true. Small, low power hub-motors can get you up any hills when they're designed for it. I guess you haven't tried a KTM Panasonic bike or a bike ith a Xiongda yet. When you have, come back and write with authority instead of spouting off your own made up theories.

OP's bike has a lot of good qualities, but unassisted hill-climbing is not one of them. He chose a bike with a torque senor, but his (presumed) unfit legs cannot sustain the force to get the maximum power from the system. It's the system design that's causing his problem, nothing to do with the motor. When his legs get a bit stronger from a bit of practice, he'll have no problem. At the moment, a system based on a cadence sensor would be better, but that will probably change with time.

So why does every mtb centre hiring out ebikes use cd units.(

And how do mentioned bikes get around speed range issue ?? Cd unit can call on entire range of bike,s gears. Hub has one ratio. Its a compromise in engineering terms. Yes they can climb a particular gradient, can same bike tackle steeper gradient? Simple answer is no. You go and try Haibikes, throns etc and come back and tell me any 250w hub drive can compete. They cant.Its an impossibility for them to do so.
But you go on kidding yourself.

 

[trex]

at the moment, I find that the best combination for hill climbing is a crank drive with a throttle. Whack up the throttle to full and pedal.

 

[Artstu]

at the moment, I find that the best combination for hill climbing is a crank drive with a throttle. Whack up the throttle to full and pedal.

A throttle on a bike is so so wrong, so that's the same as a CD on full power with a SS rather than a TS.

 

[trex]

one of the Kriegers at woosh in Southend has a gear sensor fitted. It climbs better than their Big Bear when I whack up the throttle to full because I can then shift freely between the gears while pedalling to my own rythm without fear of mashing the chain and derailleur.

 

[shemozzle999]

A throttle on a bike is so so wrong

I agree but a throttle on an electric bicycle is not.

 

[Deleted member 4366]

So why does every mtb centre hiring out ebikes use cd units.(

I don't know where you got that from. It's simply not true. I personally delivered 20 hub-motored bikes to a centre in Snowdonia. They're very happy with them.

You don't need to tell me which bikes to ride. I've ridden just about every type of electric bike there is.

As I said, when you've ridden bikes with the motors I mentioned above, come back and tell us whether you still think your bike is so great.

 

[(NoLongerRegistered#15675)]

Its not a throttle, its an accelerator.

Not tried a CD with one so cant comment but happy without one....

Bit fed up with been told I,m talking crap for saying what are basic engineering truths..
Electric motors have fantastic torque and speed ranges,way better than ICE but put a multi gear ratio capability onto one and its torque application speed range has got to be increased.
Yes there are ways around it electrically if you don't want a gear box ( with diff ratios) but it nearly always means building motor way more powerful than needed and chucking loads of current at it initially. (especially so if started under load as bikes are)

Yes hub drive no doubt are great but must have a narrower performance envelope.
My CD unit can help hill start on a 1 in 3 gradient. It can also help shove me up a hill at 15mph ( and above if dongled)
Its not just the quality of motor helping that, its the fact.both I and motor have a wide choice of ratios to select the right one for the job. If cd hasn't got one I can fit it.
You are stuck with motor ratio on hub motor ( if geared) if its not geared you are going to draw way more current and drain battery quicker.
But like I said if you are happy with hub drive, fine. OP was not. Saying he will be when he gets fitter is negating point of ebike in first place. If he got even fitter he wouldn't need ebike at all.

 

[Marwood Hill]

I'm an older bod on a bicycle and i've got breathing problems. Can only walk on the level a short distance before gasping. I have got a small cheap legal folder with a crank drive and 3-speed Nexus. With a bit of light pedal power i can climb all our hills. And they are steep hills! I do find a fully charged battery down to around the half charge gives me the most power. On occasions where i've let the battery run low, the last homeward long steep hill is a struggle for me. I have decided to fit a second battery, a 15AH. By fitting a 2-way toggle switch to my handlebars i shall then switch to this battery when climbing hills. Then switch back to the lower charged battery on the level.

 

[flecc]

Hub drives have inherent problems ,exaggerated when combined with lower power.
It simply hasn't the torque to do job so a gearbox is essential to multiply torque for initial start.,hub then has to cope with that same gear ratio throughout bikes speed range....

Not if the design is right, as D8veh said, try a bike with the Panasonic rear hub motor and you'll see what we mean.

The other day I drove a Nissan Leaf full electric car. The 0 to 60 was reasonable at around 11 seconds, but the 0 to 30 was in hot hatch territory, the take-off really something. And that's single gear, direct drive from 0 to 90 mph.
.

 

[(NoLongerRegistered#15675)]

Not if the design is right, as D8veh said, try a bike with the Panasonic rear hub motor and you'll see what we mean.

The other day I drove a Nissan Leaf full electric car. The 0 to 60 was reasonable at around 11 seconds, but the 0 to 30 was in hot hatch territory, the take-off really something. And that's single gear, direct drive from 0 to 90 mph.
.

Yes but read my post !! Look at current draw from motor !!! We don't have that capability. Leaf has regen and masssive current capability.
You aren't comparing like with like.
My fridge can start pump from Zero rpm and then run it on 100w or so..but it draws around 7 amps (well over a kW) to get there..
If our bikes did that all time we,d havee tiny range. ( Look at ranges for hubs versus cd, its for exactly this reason)

As I said earlier Bulto. Brinco would both out climb and be faster than my Haibike but look at current draw , especially initially, size of its battery and its hub drive.
Once you are limited to 250w and a reasonable size battery ( ie 400wh) and you want long steep.hill capability with a reasonable speed as well you almost have to go CD..

 

[flecc]

Yes but read my post !! Look at current draw from motor !!! We don't have that capability. Leaf has regen and masssive current capability.
You aren't comparing like with like.
My fridge can start pump from Zero rpm and then run it on 100w or so..but it draws around 7 amps (well over a kW) to get there..
If our bikes did that all time we,d havee tiny range. ( Look at ranges for hubs versus cd, its for exactly this reason)

I appreciate that, but that Panasonic rear hub motor has a perfectly acceptable range, comparable with it's competitors. Yes it can use more current when climbing, but at higher speeds and therefore a shorter time. The rest of the time it's using no more current than any other.

CD ranges when high are usually because the rider puts in more effort due to torque sensing.
.

 

[(NoLongerRegistered#15675)]

Look I,m not knocking your bike, it obviously suits you fine...
But exactly what would your hub drive be offering when starting on a 1 in 3 stony climb ?? Mine goes in lowest gear and not only am getting benefit of help the motor is drawing perhaps half ( or less) current to provide same torque at back wheel.
That's exactly why my cd uses less current..nothing to do with cadence .. Yes hub can provide the torque ( obviously) but it can not for equal current draw..
( PS my real job was designing motor control systems for rolling mills, yes not brushless DC but prrinciples on gearing / start up/ efficiency are pretty much same)
Your Hub motor can not spend its life at its optimum efficiency rpm which a cd unit can)

 

[trex]

...
Your Hub motor can not spend its life at its optimum efficiency rpm which a cd unit can)

theoretically only though, applicable on long climbs with a constant gradient.
In practice, very often you have to keep changing gears to adapt your pedalling strength to the gradient and narrowness of the path, your CD motor will have to go off then ramp up each time you change gear, reducing the motor's efficiency from its best value.
On short hills or undulating terrains where the gradient is less than 12%, I reckon geared hubs are better than crank drives, especially if you have a high torque motor like the Panasonic, Ezee or Bafang BPM. They become very effective when you ride at over 6mph.

 

[flecc]

Look I,m not knocking your bike, it obviously suits you fine...
But exactly what would your hub drive be offering when starting on a 1 in 3 stony climb ?? Mine goes in lowest gear and not only am getting benefit of help the motor is drawing perhaps half ( or less) current to provide same torque at back wheel.
That's exactly why my cd uses less current..nothing to do with cadence .. Yes hub can provide the torque ( obviously) but it can not for equal current draw..
( PS my real job was designing motor control systems for rolling mills, yes not brushless DC but prrinciples on gearing / start up/ efficiency are pretty much same)
Your Hub motor can not spend its life at its optimum efficiency rpm which a cd unit can)

I don't disagree with any of this, but I don't ride 1 in 3 stony climbs.

The essential fact is that changing down with a CD unit to use less current means slower speeds. On my powerful hub motor bikes I use more power and climb much faster in consequence. As Trex remarks, powerful hub motors come into their own as speed rises.

I've owned both CD and front and rear hub motor bikes, including all at the same time for years, so I'm well aware of the advantages and disadvantages of each. Indeed I used to use them in that fashion, horses for courses, but have ended up with hub motor only in my hilly North Downs area.

That's because I increasingly found one long slow climb I have too exhausting with a CD due to the time it took. I preferred to demolish it with more power over a shorter time.
.

 

[Deleted member 4366]

Bit fed up with been told I,m talking crap for saying what are basic engineering truths..

It's because you're wrong and you don't listen. You need to take off your blinkers and open your mind.