Which hub motor for a tandem ?
- Thread starter Lyrick
- Start date
Definitely not a direct drive one unless you know why you'd want one.
We need a lot more info to give suitable advice:
Which country are you in and are you planning on sticking to the legal requirements.
Do you already use the tandem? If so, please tell us about your rides and why you want to electrify it.
Can we some photos of the bike, in particular the hubs, forks and drop-outs, front and rear?
We need a lot more info to give suitable advice:
Which country are you in and are you planning on sticking to the legal requirements.
Do you already use the tandem? If so, please tell us about your rides and why you want to electrify it.
Can we some photos of the bike, in particular the hubs, forks and drop-outs, front and rear?
Hi, thanks for the quick reply.
I don't have access to the bike at the moment to take photos.
It's an Ecosmo folding tandem with a 7 speed freewheel rear hub and 20 inch wheels. Drop outs are 100 mm front and 135mm rear.
The wife isn't good an a conventional bike ( she has a tendency to fall off) so we thought a tandem would be a good idea.
We haven't used it yet but planning to take it to Spain with us , we spend a quarter of the year there. Lots of our friends use electric bikes and it would be useful to be able to keep up with them.
The terrain is mainly flat with the occasional short , low rise hills, so nothing heavy.
Not worried too much about local regulations, there are all sorts of bikes in use out there.
I keep seeing different opinions about Direct Drive v Geared hubs mainly with reference to low DD torque and GH longevity ( or lack of it)
I'm no stranger to electric bikes but the one I have is a mid drive and would prefer the easier conversion of a hub drive on this tandem.
Patrick
I don't have access to the bike at the moment to take photos.
It's an Ecosmo folding tandem with a 7 speed freewheel rear hub and 20 inch wheels. Drop outs are 100 mm front and 135mm rear.
The wife isn't good an a conventional bike ( she has a tendency to fall off) so we thought a tandem would be a good idea.
We haven't used it yet but planning to take it to Spain with us , we spend a quarter of the year there. Lots of our friends use electric bikes and it would be useful to be able to keep up with them.
The terrain is mainly flat with the occasional short , low rise hills, so nothing heavy.
Not worried too much about local regulations, there are all sorts of bikes in use out there.
I keep seeing different opinions about Direct Drive v Geared hubs mainly with reference to low DD torque and GH longevity ( or lack of it)
I'm no stranger to electric bikes but the one I have is a mid drive and would prefer the easier conversion of a hub drive on this tandem.
Patrick
I sold a few XF07 front hub kit in 20" rim for the ecosmo tandem.
You find prices and details by following the links below
https://wooshbikes.co.uk/cart/#/category/uid-8/front-hub-conversion-kits
https://wooshbikes.co.uk/?hubkits#xf07kit
Most of that is BS by people, who have never actually ridden an electric bike.
Generally, DD motors are better suited to constant higher speed. The average ones that you find on Ebay and Amazon are all too fast to be efficient in UK, and they're not legal. The only one I know that's legal now is the Heinzmann that's very expensive.
Why do you want to put the motor in the front, when a back one is so much better?
Main reason is ease of conversion , and I'm told that ,with the weight distribution of a tandem , traction wouldn't be a problem with a powered front hub.
It's unlikely to be ridden in the UK
I've been looking at a Mxus XF15 hub, which is geared, do you think it would be suitable ?
We've got a Woosh XF07 on a 700c wheel tandem. Works well, but definitely low on torque for bigger hills. I think it would work really well on an Ecosmo or other 20" wheel tandem.
It's getting more and more difficult to get over the crossbar on our conventional (Viking) tandem. We tried a Circe (easy local rental) and didn't really like it; we felt too compressed. My wife's view had even more of my back and even less of the countryside than on our Viking. The Ecosmo looks good, but also as if it probably would have the same issue of pushing us too close together. That may or may not be an issue for you; I'd be interested to hear any other people's thoughts on that. Maybe one day we'll splash out on a Van Raam; even lower step and looks as if it's got lots of space.
The thing about easier installation is that you save a few minutes work, but then have any disadvantages for hundreds of hours every time you ride the bike. personally, I'd rather spend a bit more time installing if it's going to give me a better ride.
Assuming that you have steel forks and drop-outs that avoid the worst problems, the main downsides of front installation are:
- Noisier
- Steering can go a bit weird depending on the geometry
- Lack of traction on steep hills.
I'd go with 48v for the extra weight of a tandem. It'll give 30% more torque than at 36v and the same current. I'd be looking at 17amps minimum unless your crew can pedal as hard as you.
You can get a nice 20AH 48b battery from Greenlance for less than £300 if you don't want to buy a complete kit from someone like Woosh.
My favourite system is a Q128 (AKM128) motor from BMSBattery, A KT controller with LCD3 that you can get from anywhere, and any decent 48v battery. That arrangement is very smoothe and quiet, immense torque when you need it, and nice power algorithms from its current control that you don't get on the more common speed control controllers.
I agree with a lot of what saneagle says, but ... I've never found lack of traction on steep hills an issue on a tandem with it's different weight distribution. I have frequently found the two wheel drive (front motor, back our pushing) helpful; especially slightly uphill on slippy grass, with the back wheel spinning out and the front wheel keeping traction.
tandem riders usually need help only with hills so 15mph speed capability is not a top issue, you don't need 48V.
On the ecosmo, the XF07 45NM torque on 20" rim with 36V 17A controller is enough. You do need a good battery, 17AH or 20AH to minimize voltage sag.
Front geared hub is also a popular choice. It's uncomplicated, more serviceable than rear hub.
On the ecosmo, the XF07 45NM torque on 20" rim with 36V 17A controller is enough. You do need a good battery, 17AH or 20AH to minimize voltage sag.
Front geared hub is also a popular choice. It's uncomplicated, more serviceable than rear hub.
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