Electric Tandems

Beeping-Sleauty

Esteemed Pedelecer
Dec 12, 2006
410
5
Colchester, Essex
evenin' all

can anyone please tell me, what is the legal wattage for a hub motor used on a tandem electric bike ?

i've had a look at the previous threads, and the usual sites, and am now completely bamboozled, cross eyed, tongue-tied and over-informed.

attempting to get my non-cycling, very phobic partner into the joys of electrics, this might be the way to do it.

there are not many electric tandems, i quite like the alloy version of the whirlwind, but would be interested to see any others you peeps might know of, maybe even a kit / adaption.


my thanks in advance

confused beeps.
 

rsscott

Administrator
Staff member
Aug 17, 2006
1,399
196
Hi Beeps,

my understanding from reading the regulations is that a tandem is subject to the same power restrictions as a tricycle i.e. 250W. According to the DTI regulations :

Maximum continuous rated power output of the motor shall not exceed:

* bicycle - 0,2kW
* tandem bicycle – 0,25kW
* tricycle – 0,25kW

http://www.pedelecs.co.uk/articles/3/1/Dft-Factsheet---Electrically-Assisted-Pedal-Cycles-EAPCs-in-Great-Britain/Page1.html

Although due to the European legislation we can enjoy a bicycle power of 250W also!

cheers
Russ
Russell Scott
Pedelecs UK
 

flecc

Member
Oct 25, 2006
53,260
30,648
That's as I understand it too Russ.

A tandem would need something with good torque rather than outright speed though, unless one at least of the riders were super fit. A Heinzmann 250 watt version would be a good choice, but in the front wheel version since a freewheel on a rear motor instead of a cassette wouldn't survive two rider input on a tandem.

Would need special power cables for the long run from the rear carrier mounted battery to the front motor, but I'm sure Kinetics could oblige.
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Beeping-Sleauty

Esteemed Pedelecer
Dec 12, 2006
410
5
Colchester, Essex
.... but in the front wheel version since a freewheel on a rear motor instead of a cassette wouldn't survive two rider input on a tandem.
Thanks Russ, 250w it is then,

just that i've looked at a couple of tandems, shop built, both with front wheel 350w hub motors, both sellers were quite sure the 350w motor was legal, one was a beautiful Holdsworth, superb quality throughout, two batteries in custom panniers at the back.

thanks Flecc, this is exactly the sort of thing i need to know, it makes sense to keep the drive at the front and sort the drive train seperately, a question... if i change the front chainwheel, to the 52t i like, should i also change the rear chainwheel to match ?

thanks,
 

Ian

Esteemed Pedelecer
Apr 1, 2007
1,333
0
Leicester LE4, UK.
if i change the front chainwheel, to the 52t i like, should i also change the rear chainwheel to match ?

thanks,
Yes Beeps, the chainwheels must match otherwise your legs will go out of sync with the stokers legs, and toes and heels will collide.. painful :eek:

In fact you leave the sync chainwheels as they are, and replace the 2nd rear chainwheel.. the one that carries the chain that goes to the rear cassette sprockets, it no doubt has a name but I don't know what.
 
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flecc

Member
Oct 25, 2006
53,260
30,648
That Holdsworth sounds great, I wouldn't worry about the 350 watt legality, nobody is going to check, least of all on a tandem. The more unusual the vehicle, the more it's the vehicle that attracts the interest rather than any nit picking attention to detail.

If a police officer saw a Hispano-Suiza car, the last thing he'd do is check the tax disc. :)
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Beeping-Sleauty

Esteemed Pedelecer
Dec 12, 2006
410
5
Colchester, Essex
Thanks Ian, i'll bear that in mind,

oh yes Flecc, much as i dispair of cars, there are one one or two that capture the essence of the spirit, that vehicle is one, as to the superlative Holdsworth, what a beauty, sheer quality, customised in Holland, about the price of a new SwizzBee, as a Russian might say "... the eye could see, but the tooth could not reach"

beeps
 

rsscott

Administrator
Staff member
Aug 17, 2006
1,399
196
The owner of the tandem, please stand up, please stand up...

Here is a photo of a tandem ridden on Sunday's rally in Presteigne:



cheers
Russ.
Russell Scott
Pedelecs UK