Best way to Electrify Tandem

[emtemt]

Hi

I am a recent convert to electric bikes.

I am so impressed that I want to add power to our tandem in the hope we can use it again.

We have some specific requirements. We live in a hilly area with a 16% hill right outside our door. I assume this would mean geared drive and lower speed but that would not be a problem. I also have a preference for brushless motors.

I was thinking of front wheel drive so we can retain the hub gears and brake already fitted but I have an open mind. I am looking for the best solution as my stoker/wife has some problem with her legs.

I would not say money is no object but I would rather pay a more and get something reliable that does the job than cut the price to the bone.

Any suggestions as to the best solution would be appreciated.

Regards

Ian

 

[RichLarry]

Electrify Tandem

Attach Jump Leads!!

Either to bike or if that doesnt work to wife!!!

 

[flecc]

Although front wheel drive on a tandem isn't ideal Ian, it's best to go for that.

My reason for saying that is that rear hub motors cannot use the cassette derailleur system and have to use multi-sprocket freewheels instead. Those are inherently much less strong than the cassette system, so far from ideal for two rider power.

In addition, the range of choice of multi-sprocket freewheels is very limited, so you could find it difficult to find a sprocket range to suit your needs.

As for the motor, an internally geared one is definitely far the better for you, and here's some front hub options:

Heinzmann - old technology brush motor, but very well made. Expensive but has high torque for good climbing. Large disc brake option, extra high torque motor option.

Alien - Low cost but quite powerful motor.

eZee - Powerful but quite expensive, disc brake option.

Tongxin Nano - small and unobtrusive, exceptionally quiet and free running, but medium power and the roller drive system not so suited to high loads.
.

 

[frank9755]

I'm not surprised you're considering adding power as that hill on your doorstep must be quite a disincentive to use the tandem. I've toyed with doing it to ours as my wife is also no longer such a powerful pedaler.

I agree with Flecc's comments regarding motors and also your own thoughts about not wanting to interfere with your existing rear brake and gear set-up.

It sounds like you are looking for help on the hills rather than speed on the flat, therefore you need a low-speed motor. The choice of motor depends on your specific requirements, in particular how much pedal power you would put in. Given that you have a tandem and do ride it up that hill occasionally, I would infer you are probably reasonably strong cyclists and are just looking for a top-up to help on the hard bits, rather than a moped-style ride. Assuming that is the case, I would recommend the Tongxin. The advantage of it is that it would give you benefit on the hills but, unlike all other motors that I'm aware of, would be virtually drag-free on the flat. If I were you I would go for the slowest motor - 160rpm - to get the maximum torque.

If I've got it wrong and you don't want to pedal much, a Suzhou Bafang (Alien) or Ezee would be a better bet. They wouldn't necessarily have more torque but they would be more robust than the Tongxin. The downside would be more resistance on the flat. The Henzmann could give you more torque, and if you got the high power one, you could have an armchair ride up the hills!

Good luck with it and do let us know if you go ahead.