Electric Trailers

[DJH]

Why bother with an electric bike when you can get a trailer to push your existing bike along for £450?
Could they be of use for load carrying on your existing electric bike?
Does the concept have any mileage?
This was taken from the ETA newsletter.

An electric trailer to push your bicycle | ETA


Happy new Year to all.

 

[flecc]

There have been others on the UK market in the past, but I'm not sure about the legality of any of them and doubt they are legal, regardless of power and top speed.

One unfortunate thing about many of them is not having a differential, meaning the drive only operating on one wheel, which can tend to side-steer the bike when under load by twisting the bike's rear to one side. The single wheel, "Bob-Yak" type designs avoid this of course.

 

[rog_london]

There have been others on the UK market in the past, but I'm not sure about the legality of any of them and doubt they are legal, regardless of power and top speed.

One unfortunate thing about many of them is not having a differential, meaning the drive only operating on one wheel, which can tend to side-steer the bike when under load by twisting the bike's rear to one side. The single wheel, "Bob-Yak" type designs avoid this of course.

As you can use a trailer with an e-bike (I seem to remember seeing a pic of your rig with a garden shed on the back) I wouldn't have thought there would be any legal problems per-se. Which wheel or wheels you might be driving is probably out of the scope of present legislation as it's never been considered.

Admittedly THIS one isn't legal in the UK primarily by reason of speed and power. There would certainly be engineering constraints though - the main one would probably be getting enough weight over those wheels to get decent traction. If that weight came from one or more heavy lead-acid batteries (or possibly a paving stone!) you'd be hauling a considerable weight up every hill even if you weren't carrying any sort of payload.

As for the diff problem, I suppose if I were designing something like that there would have to be two motors - one for each wheel. The electronics might be tricky - if one wheel breaks adhesion you'd need to cut motor power to it while keeping power on the other one.

I suspect the handling would be a bit peculiar with the drive coming from so far back - when you were cornering there would be a strong tendency to oversteer I suspect - even with two motors. The suggestion that power is being applied at the rear axle of the bike 'in the same way as pedalling' doesn't seem quite right to me - when you're pedalling all the power is applied direct to the rear wheel - nothing like what would be happening here.

Have any of the previous efforts been even remotely successful, Flecc?

Rog.

 

[flecc]

I'm fairly sure there is a legal problem Rog, based on the way the law is on e-bikes. As you know, it forms a partial exemption from motor vehicle law, based on still being a bicycle or tricycle weighing less than 40 kgs/60 kgs respectively. So it's cross referenced to what is a bicycle or tricycle.

In all English bicycle law except one, reference is made to "Bicycles, Tricycles and Bicycles with four or more wheels". The one exception is the Countryside Act of 1968 which specifically gives bridleway access to "bicycles" only, and that therefore means bicycles only, not trikes or quad bikes, though Sustrans has gained a specific trike waiver since.

Unfortunately the British exempting EAPC regulations of 1983 only refer to "Cycles, Tandem Cycles and Tricycles", specifically no mention of four wheels. The EU regulations only refer to "pedal cycles and tricycles".

Therefore any argument that the linked bike and trailer are one e-bike appears to condemn it to illegality. And of course there's the stringent requirements of the EN 15194 CEN certification for e-bike technical specification.

Although there have been many private efforts, I'm only aware of two commercial powered trailers actually being marketed though I've seen other announcements from time to time. One was Dutch from The Cabbike company intended for recumbent trikes and bicycles, with motor and SLA batteries in the base and room for goods in the upper half, shown here. The other was the £499 Trailec flatbed with a Currie Electrodrive motor on it's offside 20" wheel. Some of those might have been sold by Tony Currie from his former business and here's a photo.

 

[rog_london]

Unfortunately the British exempting EAPC regulations of 1983 only refer to "Cycles, Tandem Cycles and Tricycles", specifically no mention of four wheels. The EU regulations only refer to "pedal cycles and tricycles".

Therefore any argument that the linked bike and trailer are one e-bike appears to condemn it to illegality. And of course there's the stringent requirements of the EN 15194 CEN certification for e-bike technical specification.

I suspect that as with most things related to e-bikes, many or even most of us might be in trouble if the police really took an interest - our saving grace seems to be that we're a small minority, and most of us are not far from - or well beyond - our sell-by dates.

I've certainly seen a few e-bikes with trailers - there's a folder of some sort with one which can be seen occasionally around here.

If youngsters were in the habit of riding fast e-bikes around town centres and terrorising pedestrians it might be a different story. Fortunately they are, for the most part, priced out and would in any case go for a scooter or small motorbike until they could get a car.

Rog.

 

[flecc]

I've certainly seen a few e-bikes with trailers - there's a folder of some sort with one which can be seen occasionally around here.

There's no problem with trailers on e-bikes of course, they are covered by normal bicycle law nad I've used them for years. It's specifically an electric drive trailer pushing any bike that causes the legal problems.

 

[Deleted member 4366]

I thought I read somewhere - maybe a German forum - that trailers on bikes are not deemed to be part of the main vehicle that's towing them. They concluded that although there are rules and regulations for trailers, there's none that relate to electric power so it would be difficult to prosecute someone for using one and there's effectively no limit on power.

 

[flecc]

That could be in Germany, though it does sound rather unlikely. They tend to be willing to have laws for every eventuality, like their high speed and high power e-bike classes. Our law is very different from that though, if it's powered on the roads in any way at all, it is a motor vehicle unless exempted.

Exemptions but with restrictions are at present e-bikes of course, mobility vehicles restricted to 4 mph on pavements and 8 mph on roads, pedestrian controlled vehicles (walkalong) restricted to 4 mph and certain electrically driven toy vehicles.