Crank drive comparisons - Impulse .v. Bosch .v. Panasonic
- Thread starter Jonah
- Start date
It depends what you mean by 'low speed',with the old and very cheap 8-fun motors you really had to be up to 8 mph to get onto the motor torque curve but these BPM motors will achieve that at 4 mph. If you are meaning down at 2 mph with very high cadence then yes the crank drive will allow you to climb very steep hills with max torque,low gear,high cadence-currently no hub bike will allow you to climb steep hills at such a slow speed.
If your legs are so tired that you cannot achieve that 4 mph threshold speed then crank drive is probably best. Also crank drive and torque sensor hub drive gives very intuitive power delivery which results in a very relaxed riding motion.
Recently,because of the number of different bike styles and brands at the new London Electric Bike Company shop I have had the possibility of riding many more bikes,would really like to try the Haibike FS AM(inverted Bosch crank drive) against the KTM e-race Panasonic(rear hub drive),that would be a very interesting comparison,both bikes aimed at off-road usage-unfortunately the latest 2014 Haibikes are not available until mid August,note the price of the FS AM is £650 cheaper than the previous All Mountain bike.
I am amazed the technology and design improvements that are going into this ebike market,especially considering the size of the market.
KudosDave
It is intended to be Sunday May 18.....we are also intending to repeat the Manifold Trail,Derbyshire event on Saturday May 10. Both dates reasonably definite.
KudosDave
On flat roads, a relatively neglected advantage of crank drive is the ability to multiply speed through gearing, I can easily get to 20mph+ with light pedalling, not possible with my previous hub motor. That feeling is like the years are simply rolled back.
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But this is where a conflict can and probably will arise with the legislators. The whole point of the regulations for pedelecs is to keep them very close to remaining bicycles in every way, moderate performance and speed that doesn't need riders to be pre-qualified or have the protection of third party insurance for others.
The legislators answer to "raw power and great fun" is likely to be more regulation and the loss of the bureaucracy free life the current pedelec law gives us. The German high speed and high power e-bike classes point to how unwelcome this could be, compulsory insurance and helmet wearing, registration and number plates, and worst of all, the loss of use of the off-road cycle routes we use at present.
That's moped land.
Flecc,you know I am sympathetic with the spirit of your posting but what is happening is that these new BPM type bikes are legally offering bikes which appeal to a younger audience-we are currently selling a KTM E-race P to a 19 year old guy who has bought the bike in preference to a motorbike.
As long as we keep it legal I think the legislators will keep away,the Dft have already indicated that they will not allow the German high power classes in this country....the performance of these bikes is now such that there seems little point in purchasing illegal bikes.
Our government have still not signed up to EN15194,so any extension into further regulation could be way ahead.
KudosDave
As long as we keep it legal I think the legislators will keep away,the Dft have already indicated that they will not allow the German high power classes in this country....the performance of these bikes is now such that there seems little point in purchasing illegal bikes.
Our government have still not signed up to EN15194,so any extension into further regulation could be way ahead.
KudosDave
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Deleted member 4366
Guest
Good points Dave. The most important thing is that you choose a bike who's motor characteristics match your riding, considering your weight, how hard you like to pedal and the type of hills you're likely to regularly encounter. Everybody has different requirements.
Geebee. There's hub motors that can climb very steep hills very quickly, but everything is a compromise. You have to balance torque, speed, weight, cost, complexity, noise, battery expense and other factors. For me, the 500w Bafang BPM or CST motors are a nice compromise. They're light and free enough to ride like a normal bike. I once rode my BPM 44 miles before I switched it on. I'm 100kg and not particularly fit, and I've never found a hill that one couldn't get me up. We have 25% hills around Ironbride Gorge where I ride. I use a 5kg 20aH 36v battery, which gives about 50 - 70 miles range at legal speeds.
Geebee. There's hub motors that can climb very steep hills very quickly, but everything is a compromise. You have to balance torque, speed, weight, cost, complexity, noise, battery expense and other factors. For me, the 500w Bafang BPM or CST motors are a nice compromise. They're light and free enough to ride like a normal bike. I once rode my BPM 44 miles before I switched it on. I'm 100kg and not particularly fit, and I've never found a hill that one couldn't get me up. We have 25% hills around Ironbride Gorge where I ride. I use a 5kg 20aH 36v battery, which gives about 50 - 70 miles range at legal speeds.
I hope so Dave, but bikes like the BH Neos etc and many crank drive bikes are apparently commonly in use at assist speeds well above legality and the DfT have made known their implacable opposition to "off-road" buttons and the like.
As ever in cycling, it's all been done before. In 2004 eZee introduced the 20" wheel Quando with 30 amp controller and SB motor which whisked reasonable body weights over hills up to 14% without any use of it's single speed pedalling. It could even restart on a 12% without pedal input but was still assist-speed legal.
Tempted by that potential, eZee put the same system into the 28" wheel Torq, making it the most exciting e-bike around with 22 mph assistance that brought buyers flooding in, making it the best seller in 2006/7. This wide popularity and resulting publicity made it's illegality too blatant, so eZee sensibly backed off, replacing it with the new Torq Trekking that was 15 mph restricted. Disconnecting it's restrictor even reduced the assist further to 12 mph as if punishment for trying! Later they reduced it's controller current by a third too.
Maybe that sad conclusion will one day come to this new generation of more exciting e-bikes.
P.S. Just noticed I'd passed the 25,000 post mark, stopped counting long ago!
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I've found a 23.5% grade hill, I can't quite work it out though, the small section looks like a wall, something not quite right? Strava Segment | Ironbridge Road Climb
I remember Sanoodi had the same problem with representing short sections, gradients going all over the place, though the average was correct.
Having looked again it has a minus 295 feet elevation, clearly not a 25% ish grade hill.
Winnats at 15.2% and nearly 500 feet of ascent takes a lot out of a battery, especially if the wind is blowing straight at you as it often is.
http://app.strava.com/segments/1976323
the whole climb seems to consume half my battery with ease
http://app.strava.com/segments/612982
Winnats at 15.2% and nearly 500 feet of ascent takes a lot out of a battery, especially if the wind is blowing straight at you as it often is.
http://app.strava.com/segments/1976323
the whole climb seems to consume half my battery with ease
http://app.strava.com/segments/612982
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Deleted member 4366
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Look in the middle of the map where it says B4373, and follow that little road north. It becomes steeper and steeper until it turns left. I think it's actually a lot steeper than 25% because Google Earth gives the average of the last bit as 25%.
From Google Earth:
This one s 30%:
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off-road though. I walked down there after experiencing the pitch black bit on the stairs.
D
Deleted member 4366
Guest
There's loads of steep climbs about, but the discussion is about whether the high torque hub motors have enough torque to get you up the hills that you're likely to encounter on a normal bike ride. And BTW, my hub-motored bike will go up that hill without even pedalling, and with a battery that only weighs 3kg.
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Strava is full of errors anyway, for example this road is actually flat:
Strava Segment | Mosley St Climb
Hardknott Pass, that's a real test, long and it gets steeper and steeper with parts that are definitely in excess of 1 in 3.
Strava Segment | Mosley St Climb
Hardknott Pass, that's a real test, long and it gets steeper and steeper with parts that are definitely in excess of 1 in 3.
I'm sure it would, however there has to be some trade off, if it's capable of good high speed and exceptionally steep climbs. My car will go from 0-70mph with a third gear start, it's not very efficient to do that though.
Many readers of these pages choose not to break laws and become criminals without morals, ethics or common decency and respect. You should be prosecuted!
Melissa
That's a bit harsh and judgemental, for all you know he only uses it on private property.
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