Complete out of the box question here. scenario. pedal tricycle. I attach a trailer. I then ' power up ' the trailer so it can basically be used to ' push ' the tricycle. is this now an e-bike and so subject to e-bike regulations..?

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    Probably, though likely the regulations don't take this configuration into account, so it might slip through the cracks. Aug 28, 2021 at 12:22
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    It would probably be better to ask on Law as this is a legal question. IMO the only person whose opinion will matter is the police officer who's dealing with whatever situation makes the distinction important. Aug 28, 2021 at 13:05
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    Just think of the opportunities for power-assisted jackknifing
    – ojs
    Aug 28, 2021 at 13:11
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    @ojs Just makes the ride more fun, the same way removing both brakes would 😉
    – MaplePanda
    Aug 29, 2021 at 4:41

2 Answers 2


Yes the whole thing would be an ebike as soon as you strap the motor on and take it on a public road.

It would also potentially fall foul of "pedal assist" vs "motorised" Many countries only allow ebikes where the rider must pedal to get an assist, rather than simply sitting there as ballast and letting the motor do all the work.

Additionally, if the motor is over 300W (or whatever your country's maximum is) then it becomes an electric motorbike and needs registration/taxes etc paid. You may even need a licence plate and be excluded from cycle lanes because you're a motorbike.

I've not ridden a rig like you describe, though I have towed a heavy 100 kg trailer. Coming down off a slightly elevated railway line crossing (height 1.5 metres max) I felt the trailer pushing me, which was weird and unpleasant. Hitting the bottom of the curve felt like being in a roller coaster, and there was no way I could have braked to a stop without jack-knifing. If your motor was pushing you, it could make an incident into an accident, where liability could be on you even if you weren't the cause.

I'd suggest electrifying your trike, and towing the trailer instead.

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    Thanks... it was a bit of a stab in dark.. I was looking for a way around the e-bike regs to fit a larger motor on the trike.. as the proposed trike build itself ( some sort of camper) is gonna be heavy.. so was looking for some extra umph.. ( tourq ) to help out .. a well .. back to the drawing board.. Aug 29, 2021 at 20:04
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    I had a powered trailer once. I had my son behind me on a TrailGator™ and had him pushing me up a hill while I coasted. It was a very weird sensation...
    – FreeMan
    Aug 31, 2021 at 17:46

There are certainly powered trailers out there. For example this one which can carry up to 150kg:

eCarla Cargo https://www.carlacargo.de/products/ecarla/

Even the unpowered version has an “overrun brake with brake booster” which should make “jack-knifing” impossible. However, I assume this is also installed on the electric version and makes it impossible to push the bike.

The electric version requires you to install a pedal sensor on the bike and assists up to 25km/h. It’s limited to 250W. There is also a throttle and starting assistance up to 6km/h, though I’m not sure how that’s implemented exactly.

It’s only sold within the EU because the legal situation outside of the EU is unclear. To me this certainly implies that it’s street legal within the EU.

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    250 watt engine.. means it classified as a 'normal 'pedal bike.. I was actually thinking how to put more power in ( whilst avoiding the regs ) lol Aug 29, 2021 at 19:49

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