Hi Rachel,

Some thoughts having had the same decisions to make. 

We moved to electric after 5 conventional lightweight road tandems; primarily due to a love of hills and touring but an increasing deficit of human power!

When considering what to buy, the priority was safety (hydraulic disc brakes, no DIY conversions), longterm reliability (battery and drive train from either Bosch or Shimano) and range (75-100 miles). Better ride comfort and on-road stability/safety was more of a priority for my wife. Budget wise we didn't have a big concern as we generally buy quality and keep our kit for a long time. In the end, we bought a Moustache Samedi Tandem in touring spec, with double panniers. It has proved to be a huge positive - it's big and heavy but this makes it very stable on all road types. Range is >75 miles and ride comfort with big tyres, suspension making a big difference. Apart from the frame, all components from drive train to cycle parts are standard mainstream stuff with longterm parts and servicing back up. We've done 10,000 miles so far and the only thing I'd say that I wish was better would be chain and brake pad wear - unlike conventional tandems, electric ones are heavier and you ride them harder up hills due to the assist; so they wear out chains and brake pads more quickly - you only get 1,500 miles out of a final drive chain before it needs replacing and 3,000 miles on brake pads. 

Apart from that, whatever you eventually choose, electric assist is something you'll never leave - the smile on your face from the first ride never stops. 

Tony

Hi Rachel,

 

We have just added a cytronix motor to our Hase Pino tandem. For us it is ideal, we only use the motor on steeper hills (a lot round here in the South Downs,), or lesser hills towards the end of a ride . We average about 1% of the battery per mile when out for day rides, but used a bit more loaded for touring on the Isle of Wight. It has increased our average speed by about 2mph, and made 60+mile rides comfortable. We have only had it for 6weeks, but so far so good. We had the wheel build by Poetry in motion wheel builders as we thought building the motor into a small 20 inch wheel was a bit of a specialist thing, but with a normal tandem this wouldn't be a problem.

 

Janet 

 

 

Thanks Janet.  I have a Cytronex on my Brompton and it is fab but we would want more assist and more range on a tandem set up.

Tony - thanks for this.  It sounds like your wish list was very similar to ours.  Are you worried about the built in drive train as regards future replaceability as that is what is concerning us.  Like you we keep our kit for a long time.  Most of our bikes are 20+ years old now.

Hi we are a very enthusiastic Orbit velocity  steps 8 electric assist tandem riders bought from JD tandem 2 years ago. 3 power modes with 80 miles using mid power. Boost or max give a huge grin gliding up 1 in5 hills. Cant recommend this electric assist enough. I'm having a replacement knee at the beginning of September so hopefully be cycling again in the new year. Chat to Jamie at JD and they let you have a day jaunt before purchase which is what we did and never looked back. Have fun

John

We just installed a Cytronex C1 on our Bike Friday Tandem Twosday.  It has put the grin back!  We brought the bike down to their shop in Winchester for the measurements and we were treated very well.  Our version is the 25K/ 15mph speed limiter, but the low end torque is amazing even on the lowest power setting.  We cruise on the flats at 12-14 mph and we powered up Sawyer Hill (7-8%) in Richmond Park at 8mph.  It has added 2-3 mph to our overall average speed.   Battery life seems good for a 40-60 miler plus their normal charger is light and is easily carried to boost up the charge during a cafe stop!  We had them build our 20" wheel and so far it seems a high quality job for a reasonable price.  We are hoping that we will be able to fly with it as the batteries are 2- 99 watt/hour units and therefore below the 100 w/h limit.  We shall see on that!     

I love my Cytronex on the Brompton but we want much greater range from the tandem.

Really keen on the Thorn tandem with Rolhoff. I have one on a Roberts bike I have but I'm a bit concerned about the options for fitting a motor.

Tony - thanks for this.  It sounds like your wish list was very similar to ours.  Are you worried about the built in drive train as regards future replaceability as that is what is concerning us.  Like you we keep our kit for a long time.  Most of our bikes are 20+ years old now.

Rachel - in answer to your good point - the Bosch unit is just a standard unit - and fitted to a plethora of bikes - from cargo to commuter. If it broke catastrophically and the replacement (new one) had a different schematic and wouldn't fit, then you'd be in a bit of a pickle - and have to find a new or reconditioned unit. We spoke to Bosch before buying our Moustache to establish this fact. Their answer was that all spares (from outer casings to internals) are available 10 years after the final year of production - so it reassured us that we'd be ok for c15 years from now. Having said that in-use reliability of the Bosch unit is very high. 

Whichever way you go, You'll have a big smile on your face. 

I'd support the views of another person posting - go speak to the folks at JD Tandems - they've forgotten more than most people know about electric tandems. 

Tony

Hi Rachel,
I bought a Thorn Tandem a couple of years ago( MKII without S&S couplings as the deal was too good to pass up), to 'replace' our aging 1989 Dawes Galaxy Twin. Unfortunately I hadn't anticipated being thrown from one of our horses, or my knees starting to give out through old age and abuse. So last year I fitted a 1000W BBSHD aftermarket mid mount motor to it, technically, and legally, intended for off road use only, with the 120Nm torque and 1000 watts on hand it really makes for an ideal option for a touring tandem. The Thorn with motor weighs in at 30Kg, then adding 150Kg for the crew, and another 30Kg of 'luggage' makes the road legal 250W options just not suitable. However, I have limited it to 25Kmh (60-70 'should' be possible), and removed the thumb throttle, making it a pedal assist only, keeping it within the spirit of the law. With a 52V, 20Ah battery a days range is around 80 miles depending on use, and the assist level that is chosen.

Why not go for a Hub motor in the wheel? Having "spent" around £1000 for the Rohloff, no way was I ditching that!! Which means a front wheel motor was my only real option. Couple of issues with that ... Richard Thorn has stated that the Raven Twin fork is NOT rated for Front wheel hub motors! Secondly I had a SON dynamo front hub fitted as part of the original build, and was reluctant to part with that, so mid mount was my only option.

If you are handy with tools, and have the knowledge to maintain a tandem, then fitting a Bafang mid mount motor is relatively trivial, and takes around 6 hours ... well in my case it did as I installed it and removed it several times. Couple of things to be aware of

You loose the ability to tension the timing chain using the front eccentric, but it is possible to add a chain tensioner from Surly, wit a couple of other bits and pieces to mount it ... Or there is the Roloff chain tensioner as an option.

The kit, as supplied, throws the timing chain line off, so I 'threw' that away and kept the Thorn supplied cranks (mostly). I also bought a 40T Lekkie Bling Ring for the timing chain as that restores the chain line ... It does involve replacing the BBSHD motor cover which is very simple to do though. It also means that you need a 40T Thorn chain ring for the stokers crankset as the supplied stock ones from Thorn are 34T. Tou may need to buy the Lekkie Buzz Bar cranks to correct any Q-Factor offset created by the motor ... I bought them, but an not convinced that I needed to. A couple of Lekkie motor spacers and the Lekkie Lock nut completed what I was buying from NZ.

If I was to have my time again, I would buy the CycMotor Photon Kit now, it wasn't available at the time of my conversion, which gives you true torque assist rather than the simulated version of the Bafang. This would make it more like the Pendix kit supplied by SJS as their eBike conversion, only with more Omphhhh!

I love the conversion, and tinkering to resolve the installation issues. One thing I will say is that fitting the brake sensors to a hydraulic braked tanden is trial and error, and as I had fitted Magura hydraulic rim brakes, AND the Hope 203mm disc, to ours tuning the magnetic sensors on the first few runs out was essential. Gear changing hasn't really been altered in any way, as with a rohloff you HAVE to stop pedalling anyway, although I did buy a BBS gear sensor to make the motor cut off smoother ... not fitted it yet though.

Hope this helps, although I do suggest visiting JD Tandems to have a play around with a few options. There is a lot to be said for using a frame that is designed to fit a motor system, such as the Orbit eTandem options.

Regards

Tony

Tony - that's so helpful thank you!  I think we have been a bit green in thinking we could get a kit to fit virtually anything.  Very sad about the Thorn tandem.  We do love steel and I love another bike I have with Rolhoff.  When reading up about Pendix I noted you can't use clipless pedals which, in my view, would make it a non starter.

I guess we may have to modify our expectations and compromise somewhere along the line...

Hi Rachel,

As far as the Pendix goes, I think the issue is that the torque sensor doesn't react to well to upward pressure on the cranks, although how it can differentiate between pushing down and pulling up, when the cranks are actually connected I'm not to sure. Perhaps someone with a Pendix conversion could comment? That would also make a trip to JD Tandems at Gargrave useful, as you could try a Pendix With and Without clipless pedals

If you go with a mid mount option ... bearing in mind that it is not necessarily a buy and fit option, then either the CycMotor Photon or the Bafang BBS01/02/HD units will fit a Thorn. I went with the Bafang unit as it was relatively cheap, and it was an experiment as to how I could fit it to the tandem. I was already aware of the issue with the timing chain, but there are options to resolve that... either the Lekie route I took , which maintains the Straight timing chain, or a complete change of cranks and using a crossover approach

I have done pretty much exactly the same as Tony but with an Orbit custom build (by Bob Jackson steel tandem from JD tandems.

My nice steel tandem has. Rohloff hub and a Son dynamo although it has 700c wheel rather than 26" when looking around for a tandem we tried the Thorn and then tried the Orbit both 26" and 700c. The 700c just rolled so much nices and encoraged us to put effort in as we felt effort was rewarded rather than the slightly stodgy feel of the 26" wheeled version.

I had a guy in Weymouth do the conversion for me as he had done a friends and knew about the Lekkie chainring and cranks etc. he only charge me £200 for the work and additional parts he bought. 

I bought a Bafang BBS02 and the largest battery I could get. Although the motor is rated at 750W it is currently programmed to 250W and 25kph (so 40Nm torque). With a programming cable it can easily be changed to anything up to 750W (120Nm torque).

We have a slightly higher all up weight to Tony and partner and get about 100m out of a single charge riding on flattish but often with quite strong headwinds.

Initially the guy managed to do the installation with the motor on the front B/B without a chain tensioner but I knew I would need one once the chains started to wear. Unfortunately, because the frame was built for a Rohloff there is no gear hanger, so I had to custom make one myself to fit the dropout, mudguard and carrier eyes and then fitted a Rohloff chain tensioner. My setup does have the gear change sensor on the downshift side cable of the Rohloff (both cables move but there is some slack so I thought it would be better on the downshift side to be more instantly reactive to a downshift(it cuts out the motor). I still have to ease or stop pedalling but as the front cranks freewheel my partner doesn't always stop pedalling as quickly so for the 8/7 change I have to give warning.

Like Tony if I was doing it again, I might choose a true torque sensing unit. I did consider the Tongsheng (torque sensing) which apparently comes out of the same factory as Bafang but has a slightly different installation that requires the motor casing to be bolted to a chainstay plate (like you would fit a kickstand to). Requiring is to be mounted at the rear B/B. Since ours is a straight through drive (not crossover) front BB installation was the only realistic option for us without incurring the expense of changing the rear cranks too. Also I wasn't sure that there would be clearance from the motor casing for a crossover chainring at the front B/B and how easy it would be to get the timing chain alignment correct.

Will probably reprogram this year to 500W to get 80Nm of torque which is more akin to what the. Shimano STEPS and Bosch performance line motors deliver.

All things considered, we are reasonably happy with the setup. It ain't pretty (lots of cables tie wrapped here and there) but it does the job. If we hadn't had a custom built tandem only 5 years old, I would have gone for an Orbit Velocity or maybe a Moustache. They were only just coming to market when we bought our unassisted tandem and we didn't feel the need to go electric at that point.

I would definitely advocate a trip to JD Tandems. The team there are fantastic and will let you try as many differnt tandems as they have available. I would strongly suggest you try a few different options before commiting to the Thorn.

Hope that helps with your decision.

We have an Orbit tandem that JD converted for us using Pendix. We both wear SPD shoes with SPD pedals and the whole conversion works well for us. I would suggest a trip to Gargrave.

Apologies for the typos in my previous post. I should have read it through again but was distracted.

just to add that we also added a Stop button for the motor so that we could pedal without motor input without having to switch the whole unit off. This is very useful for tight manoeuvres such as U turns and getting through tight spaces where a gentle approach is required. The button just needs to be held in for the duration of the manoeuvre.

Hi Rachel

We too went down the road of assistance, fitted a Cytronex kit to our Santana Beyond, had to change the forks from carbon to steel as no one would comit to reliability. One battery was not enough, great I guess on a solo nut not a tandem. We have opted for a Moustache and are exceeding pleased it has the range ( we dont go mad  !! ) and two batteries wired of course " in tandem " !! Heavy yes but then what electric bike isnt ? Still have the Santana for occasional short rides but do like eveything on the Moustache except the tyres which I may well change soon