Yet Another Cycling Forum
General Category => Freewheeling => Tandems => Topic started by: Goldcrank on 25 April, 2018, 08:36:04 am
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Mrs GC has decided that she would like electric assist on our Circe tandem so she can do the school run. Any ideas for a cost effective and easy to install/de-install options?
Thanks, A
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Anything from basic wheel driven/crank sensing thru to 'the Butterfly Approach' which involves a full on frame swap and Shimano STEPS conversion.
As ever the sky is the limit - or the depth of your pockets. How much do you want to spend?
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To expand slightly.
The simplest conversion would be a 250w front wheel with pedal assist and LED control, frame mounted battery (bottle cage mounting). As long as the battery can mount on the front frame, an off the shelf kit of the appropriate wheel size is all that's required.
The same is true of a rear wheel drive conversion - as long as the LED control can be mounted on the stoker's handlebar - but I would counsel against a rear conversion because it's difficult to find a cassette based wheel and freewheels do not give the same gearchange precision, cables are more vulnerable and routing more complex.
A bottom bracket conversion will work, such as the Bafang 8-Fun - as fitted to Cycleman's Trice (https://yacf.co.uk/forum/index.php?topic=106726.0) - but there may be a transmission compromise required. To answer that question I would need detail of the existing setup.
A Shimano STEPS conversion needs a new frame.
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Really I’m looking for a cheepish, reliable recommendation for a front wheel driven e-assist. Easily installed and easily removed.
I’ve seen a few on eBay but they look like chod and I have no way of knowing if the battery is going to phritz on me in the rain.
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Check out Cyclotricity (https://www.cyclotricity.com/uk/custom/mix-match-your-own-conversion-kit.html) for a mix'n'match approach.
If you have a bottle mount, the frame battery will work nicely, no modifications required - as long as your front crank is square taper. If you're running a disc brake you will need an extra disc, plus tyre/tube/rim tape obvs. 'Tricity's motor takes a standard 160mm 6 bolt.
The motor cable splits on the front fork so running with out the motor you can leave the battery mounting and all the wiring in place with a minimal weight penalty. Although I'm pretty sure that, once you've tried it, like as not you'll never ride unassisted.
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Someone on the I Love my Circe faceache page has a pedalease front wheel conversion that they seem happy with. I looked at the options but didn't come to any conclusions, apart from that my tandem was too precious to risk a cheap one and if I was going expensive I might as well talk to circe themselves.
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I’ve seen a few on eBay but they look like chod and I have no way of knowing if the battery is going to phritz on me in the rain.
I've just ridden 9 miles in a torrential downpour and my Oxygen's battery and motor seem to have survived.
With the caveats that they are in Germany & I haven't actually used their kits, these people (http://stores.ebay.co.uk/ysbattery-2012?_trksid=p2047675.l2563) seem to be offering decent kits. The PAS is an all-in-one type and the connectors are colour-coded and easy to fit.
I don't know enough about your tandem, but I suspect a front hub won't deliver a lot of torque for such a load. A rear wheel conversion might be better in that respect, IF it can be fitted. Smaller wheels need different windings to suit the faster rotation of the wheels, but there my knowledge expires!
pedelecs.co.uk/forum might be the place to turn to for specific advice. Lots of good folk over there, but beware certain pushy trade members who will try to flog you their stuff.
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Mrs B has a Hainzmann Direct Drive system on her Helios. Its quite a high end kit and not cheap but it is good quality kit, I've had it fitted on three different bikes now.
I've also had some experience of the cheap Chinese kits that are sold on ebay. Though these are simpler bits of kit than the Hainzmann the two that we have had were both ok. One was fitted to a tandem which has since been donated to Charlotte's Tandems, the other was on my wife's Isla Bike but hasn't been used for years, I don't even think I have a battery for it any more.
Both of the cheap kits were fairly reliable is use, if I remember correctly over the 4 years or so they were in use one suffered a defective Battery Management Board and the other went through a couple of controllers. Though this can be an inconvenience the spares are cheap and readily available.
The Hainzmann been back for repair once however this was a fairly painless process as Hainzmanns man in the UK provides superb support. Aside from the support and build quality one key advantage of the Hainzmann over the cheap systems is the way it delivers power. Both the cheap kits were controlled via either a manual throttle or a crank rotation sensor, the hainzmann uses a bottom bracket torque sensor. The difference between this and a basic crank sensor is that it can deliver power proportional to rider input, rider works hard, motor responds, rider eases off, motor eases off. This makes for a much more 'bike' like experience in that you don't realise the motor is there (until you turn it off). The crank sensor systems by comparison feel much more on/off in their power delivery.
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I have an ARCC conversion on a Moulton ATB tandem (which itself is a reversible conversion of a solo).
By swapping the motored front wheel back to the original and unclipping the battery, it reverts to being unpowered.
Not cheap (just under £2K), but very good.
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That sounds like a very cool bike
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Am I right in thinking the Circe is a 406 wheel? Just checking the Cyclotricity website and it doesn't appear to be an option. Have messaged them for confirmation.
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Hi John,
No we haven't dropped them we are just out of stock.
Could be a few month before restocking unfortunately.
Regards,
Ian Byrne | Regional Manager | Tel +44 1252 757368
Bums! Guess that's 'Tricity off the menu then...