Technical Comment

Are E-Bike Throttles Legal in the UK? 2 Key Rules You Need to Know

E-bike Throttles - a Hikobike NZPulse Red with legal e-bike throttle fitted

Are E-Bike Throttles Legal in the UK? 2 Key Rules You Need to Know

E-bikes with throttles can legally be ridden in the UK, but there are two key rules that every e-bike owner should be aware of to ensure they are complying with UK law. Let’s break down these rules and the legal framework that governs throttles on e-bikes.

1. Pedal-Assist and E-bike Throttles 

The first key rule is that an e-bike must not be capable of traveling over 4mph without pedalling. This has been the case since 2016, when UK law was “harmonised” with Europe so that “Twist and Go“ throttles, which would power an e-bike up to 15mph without pedalling, became illegal. So, throttles cannot power an e-bike beyond 4mph without the rider actively pedalling.

The functionality to move the bike up to 4mph without pedalling is generally referred to as the “Walk Start” mode and is available on most UK and EU brands of e-bike. The Walk Start mode gives you a “kick-start”, or can be used to help you move the bike when you’re not riding it (eg if you were pushing it up a hill). On many brand of bikes, once the bike exceeds 4mph, the throttle cuts out, and the motor only assists through pedalling.

2. Motor Cut-Off at 15mph (25km/h)

The second rule to remember is that the motor on an e-bike must cut off once the bike reaches 15mph (25km/h). This ensures that the e-bike behaves like a traditional pedal-powered bike once it hits the maximum allowed speed. If the motor continues to operate beyond this speed, the bike may be considered illegal for road use.

Some brands of bikes interpreted the 2016 legislation to mean the throttle can continue working up to 15mph (25kph), as long as the rider is assisting by turning the pedals and the rider is operating the throttle.  If the rider stops turning the pedals the motor will cut out and bike will slow to 4mph (unless freewheeling downhill). At 4mph, the walk start facility will cut back in.

Some brands, such as Hikobike, therefore offer e-bikes with throttles that continue to assist up to 15mph when supported by pedalling.


What Happens If These Rules Are Not Followed?

If an e-bike’s throttle allows the bike to be powered beyond 4mph without pedalling, it will be classified as a “Low Powered Moped” rather than an e-bike. In this case, the bike must meet additional requirements, such as having integrated lights, mudguards, and type approval from VOSA. These regulations make it clear that e-bikes and mopeds are distinct in terms of legal requirements and motor power limits.

Different Mechanisms for E-Bike Throttles

Not all the pedal assisted throttles work in the same way.  Some throttles limit their power to the level of pedal assist that has been selected by the rider on the handlebar display. So, if you are riding in power 2 which limits the speed of assistance to 10mph, then activating the throttle will only accelerate you to 10mph.  On other bikes when the throttle is opened, the pedal assist selection is overridden and the bike accelerates at full power to 15mph.

Hikobike E-bike Throttles

When pedalling over 4mph, pressing the throttle on a Hikobike Scout or Enduro switches off the torque sensor and switches the bike to full power. The rider can then accelerate to 15.5mph with the minimum of effort.

Similarly, the Hikobike NZPulse with a rotation sensor, will develop full power without pressure on the pedals when the throttle is operated.

The ability to use the throttle for periods when cycling so that the rider can have a “rest” is a very useful function. But even on the 48V Hikobikes, the rider will have to work on hills and use the gears to assist the motor.


By following these two essential rules and understanding how different throttle systems work, you can ensure that your e-bike remains compliant with UK law. Always check your bike’s throttle functionality to avoid any legal issues and enjoy a safe and lawful ride.

 

 

 

 

3 thoughts on “Are E-Bike Throttles Legal in the UK? 2 Key Rules You Need to Know

  1. Mike Smith says:

    Can I take one tiny issue with your article on ebikes.

    > “You can also … add a throttle, to turn an ebike into an illegal motorbike.”
    A throttle IS allowed – our e-(cargo)-bike (we use to get the children to school/nursery) came with one — but it only either (a) works up to 4mph: really super useful when pushing the bike up a hill, or can increase the power (i.e. up to 250W) *while pedalling* (really handy when starting from stationary on a hill start). The nuance is here but I don’t want to start getting grief because people can see my bike has a throttle! https://www.hikobike.co.uk/throttles-on-e-bikes-what-is-legal/

    1. peter says:

      Dear Mike,
      You are quite correct and all the Hikobikes work that way. If your cargo bike has a 250watt motor and 15mph max speed, it is quite legal for your throttle to work up to 15mph as long as the pedals are turning. If your Cargo bike runs on a 48V electrics it will get the children to school with less effort.
      Thanks for your comments
      Peter Blackman

  2. Mike Smith says:

    [please delete my comment – it was intended for somewhere else + link to your very helpful page!!!]

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