The Electric Trike!

Charlie and kids on trike

Question: what vehicle can:

It still has no proper name; the jalopy, the chariot, or just the trike. But this ungainly-looking beast has become a key part of our family transport. I've never seen any commercial product using this configuration, so here's a page to explain it before the concept is lost. Maybe someone might do a commercial version one day...

Disclaimer: The manufacturers of the machine this is based on specifically advise against carrying passengers on the back, or carrying loads extending beyond the back wheels, so if you copy this then whatever happens is entirely your own responsibility.

Media Frenzy!

We featured in issue 19 (September 2005) of the splendid glossy VeloVision magazine, which specialises in less common cycling machines:

Mechanics

This whacky vehicle started life as a nearly new 2003 vintage 24" wheel Powatryke picked up cheaply on eBay. (See Powabyke's page and marketing photo.) It is the kind of thing your granny might use on a sedate jaunt to the local shops.

Pedalling drives the rear right wheel via a 3-speed hub gear. Independently, a motorbike-style twist-grip adds 250 W of thrust from an electric motor on the front wheel. You can get around using just one or the other (giving useful redundancy in the event of breakdowns), but normally you use both.

Braking is via a cheap but very effective V-brake at the front, and a rather feeble arrangement at the back with a hub brake working indirectly through a second chain and sprocket, which are really not designed to handle heavy braking forces. I'd like to replace this with another V- or even disk brake working directly on one of the wheels at some point. In the meantime I keep the front brake well maintained, while the back is at least sufficient to stop the thing in an emergency, albeit rather slowly.

Trike mechanicals

I am no racing cyclist, but I wear lycra to work and enjoy blasting through the traffic, so how do I cope with this? Other than the big yellow box, I've made just a few changes:

Purple handlebars

The big yellow box

The big box on the back is a reasonably light, yet sturdy, replacement for the original steel basket. It's made from wood, mostly scrap bits from the shed, with some plywood and MDF sheets bought specially. It took about two weekends and many evenings of "Scrapheap Challenge" effort to produce -- in the garden, in the dark, with frost condensing on my tools sometimes...

Kids in trike with door open Riding with kids in back

The size and shape arise from these constraints:

back door wide open

The back is a big door which opens so that the kids can climb in and out unaided. A parent is still required to prevent tipping as they step up though -- similar problems can occur with a really big load of supermarket shopping, if too much weight ends up too far aft. I might fit an "undercarriage" one day to get around this by propping up the back when stationary, which I can retract somehow once safely sat on the saddle. Even so, it regularly takes a full-sized trolleyful of shopping from Tesco, and has also coped with a new boxed lawnmower, stacks of timber, logs, bags of sand, and a VCR to name but a few.

Some carefully-crafted wooden shapes top and bottom make the door resist lateral pulling forces once bolted shut, providing an essential part of the rigidity of the whole structure -- it holds the sides together at the back once closed.

A maintenance hatch gives access to the big 36V traction battery and small 6V lighting battery, as well as the main bolts that secure the box onto the trike.

maintenance hatch bracing underneath

There is additional bracing underneath and at the front to resist rotation of the box backwards and forwards, and some metal straps to resist sideways deformation. It is by no means rigid, but seems quite robust against the diverse jolts and scrapes it suffers, sometimes carrying heavy loads.

High visibility from front High visibility from behind

I'm pleased to say that if you have this trike in view, there is very unlikely to be any more conspicuous object in your field of vision. The fluorescent yellow is for daylight and dusk; the band of retroreflective tape and twin 2.5W rear lights for darkness; and the pink highlights because that's what little girls expect!

Carrying kids

Having kids climb in and out via the back door, combined with the complete stability of a parked trike, is just fantastic compared with the precarious and sometimes painful process of getting children on and off conventional bike seats, or even the faff of awkward booster seats and belt fittings in the car.

Clare letting kids climb in

A removable seat back divides off a storage area behind the kids to stow their lunch bags, swimming kit or whatever. This comes out for cargo trips to give just one big volume to stow shopping in. (Or to carry one brave adult...) There are many hooks screwed in to give attachment points for bungies inside the box, but there are two special ones inside the back door just for the kids' school "book bags", which they can grab on their way out outside school.

luggage compartment

Finally a pair of 1W speakers lay hidden (and waterproofed) under the opaque polythene bags in the luggage compartment. Powered by the 6V lighting battery, these have quite sufficient oomph to liven up grey Monday morning school deliveries with some choice music from my MP3 player -- though it is up to the kids whether we have Barbie Girl on continuous repeat (often) or something with a little more street cred. Volume is strictly limited until we are out in the open!

Riding and handling

Well for starters, it's a trike. If you're used to a bicycle, it feels awful to start with. You're all over the place as it lunges towards kerbs and refuses to take corners. They say you never forget how to ride a bike, but don't believe it; after a week of trike-riding, my neurons had adjusted and I wobbled hellishly when I got back on my own bike. It takes some time to retrain one's brain to cope with both bikes and trikes.

Video (2 MB)Video clip

On a bike, you let the machine tip over to take a corner. On a trike, you point the front wheel as you would steer a car (it would probably seem natural with a steering wheel instead of handlebars, in fact). But you have to lean as well, because an upright trike has a very high centre of gravity, and unless it's heavily loaded it will tip over if you corner in a hurry. (If you've seen motorcycle side-car racing on TV, you'll know what to do.) It will still steer if you're on up two wheels, which is quite normal if cornering fast. But too fast, and you have to steer wide or fall over -- which had me taking an unplanned excursion into a bush in the driveway at work recently... so I can't claim to have quite learnt its limits yet!

The dynamics are bad in other ways too. While a bicycle is inherently unstable when stationary, at speed the tables are turned. Let go and the trike handlebars will go into an ever-increasing oscillation at any real speed, especially when going downhill. If you want to ride hands-free, a bike is actually better.

But no traction? No problem. When it's icy, three wheels are much better than two. I bought this trike to use as a "snowmobile", and the only disappointment in that regard is that it is actually quite hard to get it sliding for entertainment. The weight, two-wheel drive, and the freely-rotating back left wheel, all make it quite predictable and easy on snow and ice. Wet roundabouts, liquid mud and gravel can all be attacked quite recklessly. Any of these things have me bicycling quite gingerly, while ice and snow used to turn me to driving a car (especially after my boss broke his pelvis in a low-speed ice crash on his bike).

(As an aside, recumbent "tadpole" trikes are what you need if you want joyous handling, especially on slippery surfaces.)

In small spaces, this machine is at once cumbersome and incredibly agile. Its bulk causes problems trying to manoeuvre through constrictions and turns, though it fits through every cycle path gate I've tried -- just. I did get a bit jammed in the difficult ones behind Tesco in the early days, which is awkward with other people waiting and probably more than my body-weight in shopping to try and shift sideways... The overhang over the back wheel swings out as you turn away from something, which has caused me to bash a) the vast front window of Homebase and b) a friend's car. Embarrassing, but not damaging, in both cases.

The agile part is this: the motorised front wheel can be turned perpendicular to the frame, or even somewhat backwards, and still provide full power. This is like having a "bow thruster" on an oil tanker -- it moves the front sideways, so you can turn on the spot. This allows impossible-looking U-turns, very handy for escaping from the school amongst a jumble of parents with all manner of pushchairs, tandems, trailer-bikes and so-on after dropping off their kids.

And how fast does it go? Initial acceleration is OK, with the extra 250W of power making up for its weight. But to conform with European electric bike laws, no assistance is allowed above 15 mph, and in fact it seemed to ramp off at about 14 mph. (This increased to around 16 mph after I tinkered with the motor while investigating an electrical problem.) After the electric power is gone, you're on your own, with the heaviest and least aerodynamic bike around. With no wind I cruise at about 16 or 17 mph on the flat, which is only 2-3 mph slower than my bike; and sometimes hold 20+ mph with a good tailwind. But a bit of headwind or adverse gradient soon has me leaning on the crutch of electric power at 13-15 mph. In a really strong headwind, it is probably faster than my bicycle because of the extra power. But overall, it is definitely slower than my unassisted bike for just getting around. On the other hand, holding 15 mph is easy with two children or a huge load of shopping. The electric assist gives a "base" speed which is easy to maintain, whatever the conditions.

The width is not a great problem in traffic. True, there are times when I can't fit through gaps I would take on my bike. But generally it is not an issue. It looks big, but really it is only 20 cm wider than a typical bicycle. I can usually overtake a line of slow cars with room for oncoming traffic to slip by. Or if I'm stuck on the inside, then I can (cautiously) creep by with one wheel up on the kerb if required.

Conclusion

Well there you have it. The answer to urban transport? Well it certainly leaves our car little-used, and is a hoot to ride with the kids. And in case you're wondering, what little electricity it consumes comes from a renewable provider.

It's fun, it's a really fast way of transporting kids through the city, and it's pretty sound ecologically. What more do you need?

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