TBK kit, it all went straight forwardly and happy with the results, a light, zippy ebike.

Thanks to all here for the tips and advice

Nice pleased one is happy with the result.

Generic components means repairs and fault finding should be so easy.

I'm curious about what the grey material is on the front of the frame above the fork, and it's function.

Edited April 12Apr 12 by guerney

A nice neat conversion using generic components - love it!

By way of inspiration for others, what are the kit components used e.g. motor, battery, controller/display, PAS sensor and whether you bothered with brake switches or a throttle - thanks.

12 hours ago, guerney said:

I'm curious about what the grey material is on the front of the frame above the fork, and it's function.

Well that is a bit of a story. I want to mount a front rack or box and I was a bit worried that the existing mount wouldn't quite be strong enough to support a box and stop it swinging from side to side. So I mixed up some epoxy putty and then put that around the mount and evened it up so that there's a larger area supporting the Box once I screw it in using the existing mount. I also may use a couple of u-bolts to hold the Box top and bottom

56 minutes ago, Davoman said:

Well that is a bit of a story. I want to mount a front rack or box and I was a bit worried that the existing mount wouldn't quite be strong enough to support a box and stop it swinging from side to side. So I mixed up some epoxy putty and then put that around the mount and evened it up so that there's a larger area supporting the Box once I screw it in using the existing mount. I also may use a couple of u-bolts to hold the Box top and bottom

Is the box for the battery? @StuartsProjects made a lighweight L bracket:

https://www.pedelecs.co.uk/topic/44498-ebrompton-build/page/6/#findComment-688549

Edited April 13Apr 13 by guerney

On 12/04/2026 at 23:14, Nealh said:

Nice pleased one is happy with the result.

Generic components means repairs and fault finding should be so easy.

Yes! One reason i did the conversion is that my other bike (Velectrix small step through with a bafang mid-drive 18 months old) developed a fault with the torque sensor which could apparently only be fixed by installing a new motor. The whole Dahon bike+kit cost less that the quoted cost for the replacement.

On 13/04/2026 at 05:33, Bikes4two said:

A nice neat conversion using generic components - love it!

By way of inspiration for others, what are the kit components used e.g. motor, battery, controller/display, PAS sensor and whether you bothered with brake switches or a throttle - thanks.

The kit is this from TopBikeKit https://www.topbikekit.com/16kg-tbk74ad-36v250w-48v250w-front-motor-with-20inch-406-wheel-rim-for-bromptoncranstondohon-bike-p-1320.html?zenid=lenkm5kptcedokqotuugtavks5

I went with the standard components: the motor is, I think an AKM 74, 250w, with LCD4 display, kt controller, and yes had brake handle and cut-offs and throttle, the lightest battery which is 36v10ah, and no torque arm.

I did install the cut-offs and throttle. As mentioned elsewhere in this thread, the torque sensor had just failed on my bafang mid-drive bike. This meant that sometimes the motor did not stop when i stopped pedalling, which was a bit scary when approaching an intersection. So, i decided to take the low-risk option and install the cut-offs even though they arent essential. I put the throttle on just to see if it added much usability. Ideally, i'd like to have the throttle set to cut out at say 6kph, but there doesnt seem to be an option to have different top speeds between the throttle and PAS. So the top limit across both is the legal 25kp. I may remove the throttle (easy to do, just unplug) as occasionally I bump it when moving the bike out of my garage etc, causing unexpected start.

As with a lot of projects i probably spent 6 months deciding, 6 weeks for delivery and 3 hours to actually assemble the thing. And a lot of time measuring the size of drop-outs etc. Also, although the Dahon folds, I rarely do this, it was just the first 20" bike I saw, in good condition, and with a nexus 8 IGH which I like.

Ordering was straightforward, with pretty good communication with the site. They seem experienced with the quirks of builders. Note prices are in USD. Shipping to Oz was a bit pricey as to keep things simple I ordered the battery from them as well. Everything came in one box, well packed:

There was a slight glitch with the shipping, the kit seemed to arrive in-country quite quickly , then sat at a local warehouse for over 2 weeks. When I followed up TBK said the delay was due to 'random custom inspection' - which seemed odd - and it was despatched to me the next day. despite requiring a signature the box was just left at the front door, which was a bit of a worry as we have had a lot of delivery theft locally.

Assembly was surprisingly easy. I'd read it only took an hour or so, and the instructional video is just 10 minutes long ( https://www.youtube.com/watch?v=Rb0OSOdkqM0 ) but it was very easy. The trickiest part was actually the 'non-electric' elements, as I've done very little work on bikes since my teens. So, removing/transferring my old tyre, taking off handlebar grips, removing existing brake levers, installing the new levers and fitting the cable ends into the levers, then trying to re-align the brake pads, was the trickiest and most time consuming part, and I will take the bike to a local mechanic for a quick QA and check i puy everyhing back in the right way. I also stared at the PAS sensor etc working out which side to put it on, would i need to trim it to fit (see the video for this) but in the end the two sides of the PAS just pushed together quite neatly, then fitting the metal ring to hold the two parts was pretty easy. I would be surprised, however, if the PAS magnet ring gets a bit loose over time, as it is only really held on by friction, so some expoxy may be need.

The battery/controller bag is also a bit fiddly to squeeze everything in, and cable management is still a challenge. But again, once motor and brake levers were in, the connections just took 5 minutes.

As promised by TBK, the controller came configured. But the PAS is a bit jerky on/off, so I asked TBK for the manual and they sent the link http://topbikekit.com/LCD4%20display.pdf and will adjust settings to make take-off a bit smoother.

I also have two washers left over, as I couldnt work out where they fitted. Below is a snap of the front wheel, is anything missing?

Next steps are to customise the useability of the bike,

• putting on a front rack/box/basket to get more weight over the front wheel. there is a little bit of wheel spin currently if i set the PAS above 2 or use the throttle too heavily. Also move the battery back down a bit, possible sitting in or on the front basket

• installing a twin-leg stand

• putting on a small spring on the front wheel to stop it flopping so much

• more comfortable handlebars and saddle, as I ride it very upright. Note I have already put on a handlebar extender to lessen the crouch

Compared to my heavier mid-drive, this feels much quicker, even without power, maybe less rolling resistance due to the narrower tyres.

Its hard to judge battery distance, but it will be relatively less, which is fine as I use it for short trips to the shop, and Im happy to charge it a couple of times a week. Pushing up a hill on PAS 5 throttle really hits the battery.

Below is a photo, while waiting for a ferry, and the smaller wheels/wheelbase make it much easier getting on and off.

Happy to answer any other questions, and thanks again to those who helped with advice.

16 hours ago, guerney said:

Is the box for the battery? @StuartsProjects made a lighweight L bracket:

https://www.pedelecs.co.uk/topic/44498-ebrompton-build/page/6/#findComment-688549

more to support a basket, I am using a similar approach to StuartsProjects, of an aluminium L bracket, but to support either a basket or small box like below. and just sit the batter/controller bag in it alongside shopping bags etc. I dont fold the bike much so thats not an issue. when the front wheel flops it does catch the brake cable slighly so i may need to extend the cable or protect it somehow.

below is a photo of a pretty gruesome prototype: