Help! Legal e-bike kit recommendations

[Londondelivery]

Hi everyone,

I’m looking for advice on building a DIY e-bike conversion kit that’s as EAPC-legal as possible. With police in London starting to crack down on illegal e-bikes, I just want to be completely sure that if I ever get pulled over, my bike is fully compliant and I won’t get into any trouble—especially since I hold a driving licence and can’t afford to risk points or penalties.

I’m a delivery rider working in zones 1–2, usually covering 70–100 miles a day, so I need something reliable and efficient. I’d prefer a cadence sensing system as it’s easier to pedal during long shifts. I already have a hardtail MTB to convert, and I’m happy to source my own battery—what I mainly need help with is choosing the right kit.

I understand that to be EAPC-compliant, the bike must meet the key rules: maximum 250W continuous power, motor assistance cutting off at 15.5mph (25km/h), pedal assist only, no throttle unless it’s walk-assist up to 6km/h, and so on.

One thing I’m unsure about is whether having a configurable speed limit in the display counts as an “off-road switch” or modification, and if that could cause legal issues even if I leave it set to the legal speed.

Any guidance or kit recommendations would be hugely appreciated—thanks in advance!

 

[saneagle]

Hi everyone,

I’m looking for advice on building a DIY e-bike conversion kit that’s as EAPC-legal as possible. With police in London starting to crack down on illegal e-bikes, I just want to be completely sure that if I ever get pulled over, my bike is fully compliant and I won’t get into any trouble—especially since I hold a driving licence and can’t afford to risk points or penalties.

I’m a delivery rider working in zones 1–2, usually covering 70–100 miles a day, so I need something reliable and efficient. I’d prefer a cadence sensing system as it’s easier to pedal during long shifts. I already have a hardtail MTB to convert, and I’m happy to source my own battery—what I mainly need help with is choosing the right kit.

I understand that to be EAPC-compliant, the bike must meet the key rules: maximum 250W continuous power, motor assistance cutting off at 15.5mph (25km/h), pedal assist only, no throttle unless it’s walk-assist up to 6km/h, and so on.

One thing I’m unsure about is whether having a configurable speed limit in the display counts as an “off-road switch” or modification, and if that could cause legal issues even if I leave it set to the legal speed.

Any guidance or kit recommendations would be hugely appreciated—thanks in advance!

One slight mistake. The limit on the power is that the "rated" power mustn't be more than 250w. The motor can produce any amount of power you want.

You don't need to worry about the speed setting in the LCD. Just get one that has a password that you can set, then, if anybody ever wants to check whether it's adjustable, say they never told you what the password is.

 

[Londondelivery]

One slight mistake. The limit on the power is that the "rated" power mustn't be more than 250w. The motor can produce any amount of power you want.

You don't need to worry about the speed setting in the LCD. Just get one that has a password that you can set, then, if anybody ever wants to check whether it's adjustable, say they never told you what the password is.

Thanks for the correction and Yh that could work! Have you got any kits in mind?

 

[saneagle]

Thanks for the correction and Yh that could work! Have you got any kits in mind?

The problem is that very few kits meet my personal requirements. They all work. Before anybody can recommend what would be suitable, they'd need to know exactly what you want to do with this bike, what sort of hills you expect to climb, and how heavy you are. You could include your level of fitness too.

 

[thelarkbox]

how much mass will the bike carry? and any hills you will need to climb? ( all my zone1-2 travel is occasional and by tube)

To cover your range multiple batteries will probably be required, 36v batteries are cheaper than 48v batteries but 48v systems have more torque for hills. Im NOT suggesting connecting multiple batteries to power a bike but carrying/stashing spares for exchange when and if necessary.

 

[Peter.Bridge]

70-100 miles of delivery riding a day sounds incredibly tough, you will need something pretty heavy duty ! I would echo the idea of having a spare battery that you could swap over.

 

[Londondelivery]

The problem is that very few kits meet my personal requirements. They all work. Before anybody can recommend what would be suitable, they'd need to know exactly what you want to do with this bike, what sort of hills you expect to climb, and how heavy you are. You could include your level of fitness too.

i need this bike to do deliveries on for about 70-100 miles, 90% flat land but I go over London Bridge sometimes. I’m £90 kg and with food and equipment I’m around 95-97kg and I’m quite fit but ideally I’d like something that makes it easy as possible, which is why I’m looking for a cadence system.

I will probably buy 2 batteries and I live Close to where I work around so i can recharge a battery while using another.

 

[Londondelivery]

how much mass will the bike carry? and any hills you will need to climb? ( all my zone1-2 travel is occasional and by tube)

To cover your range multiple batteries will probably be required, 36v batteries are cheaper than 48v batteries but 48v systems have more torque for hills. Im NOT suggesting connecting multiple batteries to power a bike but carrying/stashing spares for exchange when and if necessary.

everything so me and food and stuff should be 95-97kg, and not many hills just bridges that span the river Thames but 90% flat land. Yh I’m good with batteries I will probably carry 2 and I can recharge 1 as I use another as I live where I work. So I can swap them.

 

[Londondelivery]

70-100 miles of delivery riding a day sounds incredibly tough, you will need something pretty heavy duty ! I would echo the idea of having a spare battery that you could swap over.

Yh so far I’m using the forest bikes that you can’t rent, but for my own bike yes I’ll be using 2 batteries, and I’ll be recharging them if need be as I live where work

 

[saneagle]

i need this bike to do deliveries on for about 70-100 miles, 90% flat land but I go over London Bridge sometimes. I’m £90 kg and with food and equipment I’m around 95-97kg and I’m quite fit but ideally I’d like something that makes it easy as possible, which is why I’m looking for a cadence system.

I will probably buy 2 batteries and I live Close to where I work around so i can recharge a battery while using another.

Hub-motors are generally more reliable than crank ones, and they can bale you out if you get any problem with your drive train. It's difficult to gauge how much power you need, but I'd go with 48v to get more power options.

You can divide motor controllers into two groups: speed control, where each assist level gives a different speed limit and the same power; or current control, where you get different power on each assist level and the same max speed limit. IMHO, current control is much better because you can always choose how hard you want to pedal. Also you can turn the power down a bit if you want to conserve battery. If you tried the two, I can guarantee that you'd choose current control.

The problem is that hardly any ready-made kits have current control, and those that do only have front motors and stupid stuff like that. I'd buy the motor and controller from Chinese re-sellers so that I get what I want, but it works out a bit more expensive.

The Woosh 48v rear hub-motor kit is an absolute workhorse and ideal for what you want, apart from the speed control controller. If you don't like it or if it's not efficient enough, you can always change the controller later for about £80.

You really need a 20Ah battery with that motor, which you can get from Greenlance for a good price. I'm not too sure what you can get from Woosh, but the standard 13.6ah downtube one is too small. It doesn't really make sense to buy the whole kit and throw away everything except the motor, but it's not easy to get those big cassette motors marked 250w.

Easiest option would be the Woosh TSDZ8 crank-drive kit. They say it's a torque sensor motor, but it behaves a lot like a cadence sensor one. It's easy to get good power without much effort. They're pretty quick and easy to install. The only problem is that they're not as bullet proof as those big cassette hub-motors, and slightly harder to fix, plus a lot more wear on your drive train. Also, you can buy them without a battery, so you can get your batteries from Greenlance or Yose.

Basically, there's no answer, just loads of options and none quite like what you want.

 

[Peter.Bridge]

There's a few places that does 250w kits : Woosh, Yosepower PSWPower, topbikekit

I would suggest a geared rear hub motor and put the battery on the downtube. Maybe a 48v kit for power

 

[Peter.Bridge]

The Woosh 48v rear hub-motor kit is an absolute workhorse and ideal for what you want, apart from the speed control controller. If you don't like it or if it's not efficient enough, you can always change the controller later for about £80.

You really need a 20Ah battery with that motor, which you can get from Greenlance for a good price. I'm not too sure what you can get from Woosh, but the standard 13.6ah downtube one is too small. It doesn't really make sense to buy the whole kit and throw away everything except the motor, but it's not easy to get those big cassette motors marked 250w.

Would @Woosh sell you the a 48v rear DWG22C hub wheel , controller and display and you can buy a bigger battery (48v 20Ah) separately ?

 

[Bobbo1260]

I have purchased two of the Yosepower front hub kits, one for my trike and one for bike. They both have 250w 36v motors with a standard set 15mph limit Which can be tweaked.
The only thing that makes it illegal is the throttle takes you to 15mph but Saneagle has kindly supplied me a way of of how to limit the thumb throttle to a variable speed limit which I’ll be making at the weekend.
I’m a 100kg and the specialised step thru bike it’s installed on now weighs 24kg. kit installation is easy enough with some spanner’s and the supplied Allen keys and crank arm remover.
When I had a suspected dodgy controller they sent me a replacement within 3 days. The battery is 15 amp but they also do 17amp.
There are some hills where I live and it gets up them ok with some assisted pedalling.
I don’t understand when people review an e-bikes performance up a hill on throttle only and then slate it, when it’s designed as a pedal assist kit.
The kit I bought a couple of weeks ago cost £333 all in. Delivery took about 3 days.
There have been some comments about not mounting a front wheel in aluminium suspension forks as the drop outs can snap even with a torque arm installed.
Having spoke to a trusted bike fitter he advised ensuring the surfaces of the wheel the axle nuts bears against is truly flat as the nut has a larger contact surface than the original quick release it was designed for, and if the nuts are not seated on a flat surface it will side load the drop out.
I also had to reduce the diameter of the nut so it did not interfere with the external lawyers lips and fitted an external tooth washer to aid grip and ensure even pressure is applied across the dropouts face.
Having showed the install to the bike fitter he said it will be fine without a torque arm at a mere 250w.
To be on the safe side I put the set up to a structural engineer at work who asked the torque values and diameter of the wheel and he showed me a load of calcs which made no sense to me, and he said using a 250w motor would be OK, but anything above 500w could be risky, allowing for 2:1 FOS.