Hi Charles. The Cytronex is reasonably easyy to fit and very easy to use. I have one in a single bike that I used for several years working as a cycle instructor. It is good for about 40 to 50 mile used on the lowest setting. I am not sure that the torque would be enough for a tandem but talk to Cytronex as I believe they have different versions. It is activated by a simple freewheel or sprocket rotation sensor and is not input torque sensitive.

One thing that you need to check before buying is the compatibility with your front forks. It relies upon the tight fitting of flats on the axle into you fork ends i.e. it doesn't have a torque arm. I would be a bit worried about just relying on the hardness of the fork ends on a tandem as with the extra stress especially on hills it might end up opening up the fork ends.

You need to talk to the guy who owns the company and check about that. They might have a talk arm version by now.

Just give them a call they are very helpful.

stephen

I think that the Cytronex system uses a form of cadence sensor rather than a torque sensor.  Having ridden with a torque sensor for the last 10 years on our S&S Pino, we had to change to a different e-system this year because our old system failed and is no longer made.  The new motor (Bafang) uses cadence sensing, not torque sensing.  On the basis of this experience I would strongly advise that whatever system you buy, you get one that uses a torque sensor as this gives a much more intuitive ride.   

Having done further research recently I think that one promising system worth investigating is the CYC Photon, although I've never tried one of these.  They are quite expensive, but still cost less than we paid for our discontinued system 10 years ago.  It is a mid drive system so the power assistance can make use of the bike's gears.

I actually wrote a letter to The Times on this subject recently and was pleasantly surprised when they published it.

We do not have a Cytronex. We have been into the shop (local to us) a few times for other things and they've always been helpful.

The Cytronex kit is neat. It is very highly priced for what it is, with a very low capacity battery and low torque motor.
Any parts are likely to be expensive (eg 495 for a 198Wh battery), and may even become unavailable. 

Consider Woosh as an alternative. https://wooshbikes.co.uk/?hubkits#xf07kit 
We have had this kit for 6 faultless years on a fairly basic Viking tandem.
With a bag battery (still lowish capacity but much more than the Cytronex) it now costs £449. (ours came with a different downtube battery).
The torque is 42NM, quite low but again higher than the 35NM I believe the Cytronex has.
Neither will drive you up a steep hill on a tandem without lots of extra help from both riders.

The Woosh parts are all generic; you might not get a like for like replacement but spares will always be available.
It will be a little heavier than the Cytronex, and probably not quite as neat.

Woosh have exceptional pre and post sales customer support.
Fitting was easy, and would be with the Cytronex as well.

As in the earlier post, check your front forks are suitable. 
Steel will probably be OK. For other forks check with Cytronex or Woosh before going ahead. 

Front wheel is not  the best place for a motor, but this is not so important with the different weight distribution on a tandem.
We have sometimes (slight uphill slippery grass) even found it to help as both wheels have traction.

~~~

We've just moved on to an even more basic Ecosmo tandem; our rides are getting shorter and I was finding the crossbar a pain.

We might be selling the Woosh kit 2nd hand fairly soon; but the downtube battery might not suit.

You are welcome to try the Woosh/Viking to get an idea of what to expect. Winchester.

Hi Charles

I fitted the system on my Santana Beyond, very good system , went to their shop in Winchester, very helpful, trieda sosl with the system fitted, great !

Easy to fit

Found it not quite man enough for a Tandem, ours is Carbon and Titanium so light, after research found I had to change the forks from carbon to steel, no one would provide test info covering the torque on carbon. 

I wanted a second Battery, they we not able to provide, so added a system to link when we flattened the first one.

THEY DIDNT LIKE THIS AT ALL.

I feel the system is not powerfull enough for a Tandem better suited to a solo

Sorry that should be torque as in the first two times I used the word!

Sorry that should be torque as in the first two times I used the word!

My husband fitted a cyctronex motor to our Hase Pino tandem. For our usage it works well. We moved from a less hilly area to the South Downs and wanted something to speed us up on the hills. We only use the e assist on hills, and if we are careful it will do 60 miles if it is reasonably hilly, more if flat ( as we would not actually be using it!,) It also allowed us to keep our full gear range, so on the odd occasion when we have run out of battery we can still get home, just more slowly, even if we have to go over Old Winchester Hill. We chose this system because we wanted something small and light, to give us a small amount of assistance, and because we live near Winchester where the Cytronix shop is. Another tandem couple that we know quite well have one on their conventional tandem and like it, but again, they don't use the e assist for their whole ride, just for the hills. Hope this is helpful.

I fitted a Cytronex system to my tandem some 6 years ago having read an article in the Tandem Club magazine.   The majority of our "outings" involve Cornish hilly terrain.  We have always been delighted with it. Cytronex provided a motor with more torque, for a tandem.  The only problem when fitting is to ensure that the front fork cut-outs will be deep and wide enough to accommodate the increased size axle and the torque washers.    Mine did require a small adjustment initially. Our tandem is a Thorn with S&S and Rohloff.   There's never been a problem in separating the frame and relocating again.    Cytronex have always been excellent to deal with and 4 friends have subsequently fitted their product to solo bikes.   Would definitely recommend. - John [Cornwall]

We have a second-hand Trek tandem on which a Cytronex motor had been fitted at their Winchester shop.  Like others we wanted it for some extra assistance to keep up with our younger fellow riders! We don't know how old the battery is and suspect it may be a bit old. When we took it on a hilly tour to Malmesbury and back last year we did find we needed to re-charge it at lunch-time on hilly days (no problem - pubs and cafes quite happy). We believe that the forks were replaced when it was fitted, possibly not perfectly as my captain complains that his toes hit the front wheel when turning which Trek would probably not have planned..Overall we find the Cytronex great for our purposes - it's a heavy tandem and we total 21 stone (plus paniers when touring).