Hub gear or derailleur for an ebike?
Re: Hub gear or derailleur for an ebike?
I don't think there's much choice here. The configuration rules out a front wheel motor (actually it would probably work, but the handling might take a bit of getting used to), which leaves crank or rear hub.
A crank drive cargo bike is going subject its transmission to greater than design stresses (twice the weight and twice the power). I think I'd go for the derailleur; chains and sprockets are going to fail regularly but at least they are cheap and easy to replace.
Rear hub drive will stress the transmission less, but the motor occupies the same space as an IGH, so only derailleur is possible. I'm sure an integrated hub motor / IGH is technically feasible, but as far as I know no one makes one.
Assuming the trike is a swing box design, I'd go for the rack mounted battery. The cables which carry power from battery to controller will be shorter and not moving with the steering. Even cheap hub motors have a life span exceeding 10,000miles and the main wearing parts are replaceable (look for one with a cover plate retained by screws).
A crank drive cargo bike is going subject its transmission to greater than design stresses (twice the weight and twice the power). I think I'd go for the derailleur; chains and sprockets are going to fail regularly but at least they are cheap and easy to replace.
Rear hub drive will stress the transmission less, but the motor occupies the same space as an IGH, so only derailleur is possible. I'm sure an integrated hub motor / IGH is technically feasible, but as far as I know no one makes one.
Assuming the trike is a swing box design, I'd go for the rack mounted battery. The cables which carry power from battery to controller will be shorter and not moving with the steering. Even cheap hub motors have a life span exceeding 10,000miles and the main wearing parts are replaceable (look for one with a cover plate retained by screws).
Re: Hub gear or derailleur for an ebike?
there are such things as hub drives that use a sprocket that is added to the LH side of the rear wheel and a remote motor/gearbox. This has plenty of scope for being done badly but does allow an almost free choice of rear hub, including IGHs.
BTW I have seen lots of cheap hub motors fail in a lot less than 10000 miles and a very common fault is that the drive ring fractures inside the hub; this means that replacing the innards only isn't going to work.
cheers
BTW I have seen lots of cheap hub motors fail in a lot less than 10000 miles and a very common fault is that the drive ring fractures inside the hub; this means that replacing the innards only isn't going to work.
cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
Re: Hub gear or derailleur for an ebike?
I like the extra sprocket idea too. Does it use disc brake mounts or roller brake splines? The only one I've seen was a mid-mounted IGH on a trike which used the spoke flange to mount the sprocket, something which couldn't be done if it were built into a wheel.
I'm have been considering something similar for a front wheel. At the front I can use a single speed rear hub and that will provide the freewheel. It will also permit a drum brake. Reliability and reparability is the target, as usual, but so far a standard hub motor is proving quite difficult to break.
I'm have been considering something similar for a front wheel. At the front I can use a single speed rear hub and that will provide the freewheel. It will also permit a drum brake. Reliability and reparability is the target, as usual, but so far a standard hub motor is proving quite difficult to break.
Re: Hub gear or derailleur for an ebike?
one I have seen that looked incredibly crude (but actually worked OK) bolted to the spokes ( ) and was located radially by pegs that engaged with the hub flange. It is meant to work with rear wheels that are (over) built with 12G spokes, I think.
cheers
cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
Re: Hub gear or derailleur for an ebike?
FWIW.
I've run my system for around 2 weeks now (roughly 500 miles).
It's a pedal driven system using a dangler.
Can't say I'm too fussed about the 'extra' power routed through the transmission (since overall it's no faster than I used to be, and I didn't wear out transmissions at a fast rate) although obviously if you are both using the motor AND standing on the pedals there will be an increase in load.
Things I like about it.
It handles hills and headwinds well. Fairly obvious when you think about it since you can simply drop one or more gears.
It's very quiet, don't know if it's quieter than a hub motor - but anecdotally I can hear hub motored bikes as they go past (apart from the ones I can't ). I can barely hear the motor on mine.
Downsides.
Changing down can be a bit teeth clenching due to changing down under power, although I'm teaching myself to momentarily stop pedalling, drop a couple of gears and start again. Only takes a second or so and the change is then silky smooth. Changing up otoh is a nice solid 'snick'.
(If you have motor cut offs attached to the brakes then a quick tap of the brakes will achieve the same thing, there are also gear change cut offs - I have neither.)
My current gut feelings are if I had a choice I'd prefer a hub gear (although reading this thread is giving me second thoughts).
I've run my system for around 2 weeks now (roughly 500 miles).
It's a pedal driven system using a dangler.
Can't say I'm too fussed about the 'extra' power routed through the transmission (since overall it's no faster than I used to be, and I didn't wear out transmissions at a fast rate) although obviously if you are both using the motor AND standing on the pedals there will be an increase in load.
Things I like about it.
It handles hills and headwinds well. Fairly obvious when you think about it since you can simply drop one or more gears.
It's very quiet, don't know if it's quieter than a hub motor - but anecdotally I can hear hub motored bikes as they go past (apart from the ones I can't ). I can barely hear the motor on mine.
Downsides.
Changing down can be a bit teeth clenching due to changing down under power, although I'm teaching myself to momentarily stop pedalling, drop a couple of gears and start again. Only takes a second or so and the change is then silky smooth. Changing up otoh is a nice solid 'snick'.
(If you have motor cut offs attached to the brakes then a quick tap of the brakes will achieve the same thing, there are also gear change cut offs - I have neither.)
My current gut feelings are if I had a choice I'd prefer a hub gear (although reading this thread is giving me second thoughts).
Re: Hub gear or derailleur for an ebike?
please bear in mind that the short lives of such parts that I mentioned are in the context of carrier bikes in hard use, not solos with an e-assist to maintain a modest speed.
cheers
cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
Re: Hub gear or derailleur for an ebike?
Brucey wrote:please bear in mind that the short lives of such parts that I mentioned are in the context of carrier bikes in hard use, not solos with an e-assist to maintain a modest speed.
cheers
Good point.
Out of interest, what IGH's would you recommend for a crank driven e-bike?
Re: Hub gear or derailleur for an ebike?
Nexus 7, Nexus 8 (premium) are good choices. The latter is more efficient and should last a bit longer before the planet gears wear out. Both can be made to last better if they are lubricated properly (i.e. not with the shimano grease).
However both suffer from the same issue being that there is a shift (4-5 in the 8s hub and 5-6 in the 7s hub) that requires a sliding clutch to move. If this shift is repeatedly made whilst the drive is under load the hub tends to suffer somewhat.
cheers
However both suffer from the same issue being that there is a shift (4-5 in the 8s hub and 5-6 in the 7s hub) that requires a sliding clutch to move. If this shift is repeatedly made whilst the drive is under load the hub tends to suffer somewhat.
cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
Re: Hub gear or derailleur for an ebike?
IIRC, the high end (Kalkhoff?) hub gear / crank drive e-bike I tried a while back had a power cut system built into the gear changer. Necessary for any sort of decent hub life, I'd have thought? Inclines me towards geared hub motors with cassette.
"42"
Re: Hub gear or derailleur for an ebike?
get the best of all worlds SRAM DD3 or DD3 pulse
https://www.sram.com/sram/urban/product ... fujluhw0h9
https://www.sram.com/sram/urban/product ... fujluhw0h9
NUKe
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Re: Hub gear or derailleur for an ebike?
NUKe wrote:get the best of all worlds SRAM DD3 or DD3 pulse
https://www.sram.com/sram/urban/product ... fujluhw0h9
Given the known fragility of SRAM DD hubs when subject to power shifting, that doesn't seem too clever (Anyway I thought SRAM had stopped making DD hubs )
"42"
Re: Hub gear or derailleur for an ebike?
the DD3Pulse is a new one soecifically for e bike with BB motors
the DD3 non electric I think your right but is still available and still on the SRAM website
https://www.sram.com/sram/urban/family/ ... fujluhw0h9
the DD3 non electric I think your right but is still available and still on the SRAM website
https://www.sram.com/sram/urban/family/ ... fujluhw0h9
NUKe
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Re: Hub gear or derailleur for an ebike?
any DD will have the same crappy arrangement for the gear1/gear2 drive ratchet and is anyway now an obsolete product that won't be supported. It may be on their website but so what? They won't be making any more hubs or any more spare parts for them.
http://www.bicycleretailer.com/international/2017/02/15/sram-ends-sales-internal-gear-hubs#.WgSVLPXXLMz
cheers
http://www.bicycleretailer.com/international/2017/02/15/sram-ends-sales-internal-gear-hubs#.WgSVLPXXLMz
cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
Re: Hub gear or derailleur for an ebike?
Hi all thanks for the input so far,
I thought this was relatively straightforward, how wrong could I be!
I have now read the pedalecs forum, and a few others, being prompted by comments in this thread. As I now understand, but could be wrong, how you use the IHG will determine the longevity as well as the type. But this is not particularly logical initially, for example, due to the Construction of the Nexus 8 which is more robust than the Nexus 7 apparently, gear 5 is the most robust gear. So it was recommended that to do a power assisted hill start you should start in this gear not the lowest gear, as it can cope with the torque much better.
Certain designs are better than others.
Looking at the other route, derailleurs and associated drive components will be worn out by a hub drive, but they are relatively inexpensive, being 7 or 8 speed. I am familiar with servicing them so would be happy to do this, and I could alter the gear range quite easily if required.
To fit a custom system is going to be costly, and may never work properly.
So after going round in circles, I think that I may be better off picking a system that the manufacturer of the cargo bike has as one of their options.
Unless I am missing something here???
Martin
I thought this was relatively straightforward, how wrong could I be!
I have now read the pedalecs forum, and a few others, being prompted by comments in this thread. As I now understand, but could be wrong, how you use the IHG will determine the longevity as well as the type. But this is not particularly logical initially, for example, due to the Construction of the Nexus 8 which is more robust than the Nexus 7 apparently, gear 5 is the most robust gear. So it was recommended that to do a power assisted hill start you should start in this gear not the lowest gear, as it can cope with the torque much better.
Certain designs are better than others.
Looking at the other route, derailleurs and associated drive components will be worn out by a hub drive, but they are relatively inexpensive, being 7 or 8 speed. I am familiar with servicing them so would be happy to do this, and I could alter the gear range quite easily if required.
To fit a custom system is going to be costly, and may never work properly.
So after going round in circles, I think that I may be better off picking a system that the manufacturer of the cargo bike has as one of their options.
Unless I am missing something here???
Martin
Re: Hub gear or derailleur for an ebike?
if you have a good supplier of such bikes near your, it may well be that they offer (say) a hub motor e-upgrade that is not offered by the manufacturer and they have a considerable amount of expertise with such systems. SInce warranties first lie with the supplier rather than the manufacturer, you are arguably pretty well in their hands anyway.
I don't think that you have much to lose by going down this route, unless the e-upgrade is in some way specifically prohibited by the manufacturer.
BTW with a Nexus 8 hub, gear 5 is direct drive.
cheers
I don't think that you have much to lose by going down this route, unless the e-upgrade is in some way specifically prohibited by the manufacturer.
BTW with a Nexus 8 hub, gear 5 is direct drive.
cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~