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Swytch e-bike kit review: Electrify your folding bike on the cheap

Our Rating :
Price when reviewed : £799

Not the most polished of rides but Swytch’s folding bike-conversion kit is ludicrously compact and light


  • Amazingly lightweight
  • Simple to fit
  • Inexpensive compared with Brompton Electric


  • May void your Brompton warranty
  • A tad rough around the edges

When I reviewed the Brompton Electric, one of the main criticisms I had was how expensive it was. Although Bromptons aren’t cheap in the first instance, charging £2,695 for a power-assisted version just felt unreasonable, especially when the motor, battery and other necessary components cost a fraction of the price to source from China.

There is an alternative, however, for folks attracted to the folding prowess of the Brompton who don’t quite have that amount of money to spend: an aftermarket e-bike conversion kit from Swytch.

Folding Swytch e-bike kit review: What you need to know

The Swytch conversion kit is very simple to fit, although it’s worth noting that doing so will void your warranty. Not so much a consideration if you have an older Brompton but certainly something to think about if you’re buying from new.

It comes in the form of a pre-built wheel with a 250W hub motor fitted, a small lithium-ion battery pack and control unit, together with a charger, all the cables and brackets you need and a cadence sensor that fits around the left side of your bottom bracket.

It doesn’t take a bicycle repair genius to fit, either. Just swap over the front wheel, attach a few other components and connect some cables together and you’re ready to ride.

READ NEXT: Brompton Electric – the best folding e-bike

Folding Swytch e-bike kit review: Price and competition

The Swytch kit for the Brompton is available in two different flavours: the Eco (35km/21.7-mile range) and the Pro (50km/31-mile range). It was initially only available on Indiegogo but has since launched on both Amazon and the Swytch website – though stock is non-existent. The price starts at around £400 for the Eco kit I’m reviewing here and £491 for the Pro. Those are Early Bird prices, though, and around £500 for the Pro kit.

Even once the price rises to the full amount (£799 and £999), though, this still compares favourably with buying a pre-built Brompton Electric, which costs from a minimum £2,695 for the most basic official model. If you buy the (roughly equivalent) Brompton M3L and fit it with the full-priced Eco Kit you’ll be saving nearly £1,000.

There are other folding e-bikes available for around the same price, notably the Decathlon Btwin Tilt 500, which sells for £900. We like it a lot but it doesn’t fold up as neatly as a Brompton Electric or a Swytch-upgraded Brompton.

Check stock now at Swytch

Folding Swytch e-bike kit review: Fitting and features

Our test Brompton came with the Swytch kit already fitted so I can’t relay any real-world experiences as to how easy it was to fit. However, I’ve built bikes before and retro-fitted a couple of e-bike kits to my personal bikes and this kit looks pretty straightforward to me. Even if you run into trouble, Swytch offers one to one video support calls (you’ll have to schedule them, mind) to help you through.

If you have lights or a bell fitted to the centre part of your handlebars, you’ll need to move them. Other than that, assuming you have the correct tools, you should be able to complete the upgrade in half an hour or so. The first job is to swap out the front wheel – you’ll also need to swap over your tyre and inner tube, naturally. Next, you clip the “magnet wheel” to the left side of the bottom bracket and then cable tie its sensor to the frame so the motor knows how fast you’re spinning the pedals.

Then attach the battery bracket to your handlebars, run the cables along your Brompton’s existing cabling and you’re almost there. The only small jobs that remain are to plug everything together – the connections use waterproof and colour-coded Higo connectors so this is a doddle – and to replace the peg that’s there to clip the handlebars to the frame when the bike is folded with a longer one. This ensures the forks don’t hit the motor when folding the bike. It also means the fold isn’t quite as neat as it is on the official Brompton Electric but it only adds a centimetre or so to the width overall.

That’s pretty much it for the standard kit, but there are some optional extras. You can add brake sensors for that extra peace of mind, so the motor cuts out when you tweak the brake levers. My test bike wasn’t fitted with them and I didn’t have any problems. It’s also possible to purchase a slightly neater pedal sensor but you’ll need to remove the left-hand crank to fit it, which is – frankly – a pain and requires specialist tools.

Once the kit is fitted, though, it’s remarkable how little impact there is on both the look and the overall weight of your bike. The motor adds 1.5kg to the bike and the smaller battery is only 1.5kg so with that stowed in your rucksack it’s almost as easy to lift as your regular bike. For reference, the official Brompton Electric’s motor is over 2kg and the battery weighs 2.9kg. The Swytch has it beaten here.

The only moan I have is that, when folded, the extra weight of the battery bracket can cause the handlebars to detach from the frame clip as you’re carrying it. Swytch will be selling an optional luggage mount bracket, though, so it is possible to avoid this happening if it becomes an issue for you.

Check stock now at Swytch

Folding Swytch e-bike kit review: Ride and performance

With the battery on the handlebars or the luggage mount – my test bike was provided with both so I could try them out – the Swytch-fitted Brompton handled well and provided a surprisingly strong level of power assistance.

As per UK law, the 250W motor will only provide assistance up to 15.5mph (25km/h), and there’s no throttle, but this is plenty enough speed for the typical journey a Brompton is used for. I used it for my whole commute of around 11 miles each way and never felt wanting for speed.

If anything, at low speed, I preferred the feel of the Swytch kit to the official Brompton electric. The power kicks in a little earlier and with 40nm of torque on tap it gives a nice thrust of acceleration, bringing you up to top speed in a jiffy. There are five power settings to choose from, selectable via buttons on top of the battery pack and you can entirely disable the motor if you want to ride without assistance – there’s no drag from the motor so it feels just like riding a regular Brompton.

Where the Swytch kit falls short of the official Brompton Electric is refinement. When you hit that 15.5mph limit, you can feel the motor disengage and then re-engage as you fall back below the limit again, resulting in a slightly lumpy feeling ride. Faced with a steep hill, I also found that unless I was in the right gear, the motor had a tendency to cut in and out occasionally if I didn’t apply enough power to the pedals. An appropriately low gear keeps that behaviour to a minimum, though, and ensures you don’t have to pedal too hard.

Range, inevitably from such a small battery pack, is limited, but I found it coped fine with my 11-mile commute and with capacity to spare. With the power set to maximum power for half the ride and at level four for the rest of it, I had two red LEDs out of five showing on the battery come the end, which was fine.

The official range, at lower power levels, is 22 miles (35km) according to Swytch and ten to 15 miles at full power, which is pretty good for something so small and compact. The larger battery provides up to 31 miles (50km) of assistance. The Brompton Electric’s bigger battery delivers 20 to 45 miles of range.

Folding Swytch E-Bike Kit review: Verdict

It’s still not cheap when you consider the components provided, and don’t forget you’ll be voiding any remaining warranty you have, but the Swytch conversion kit does offer fantastic value for money versus the official Brompton Electric. Even without any kind of early adopter discount, the overall saving will be nearly £1,000, which is not to be sniffed at.

Sure, it doesn’t quite have the polished feel as the Brompton Electric and it’s rough around the edges when it hits its 15.5mph assistance limit but, for the most part, this kit hits the mark. It’s very light, simple to fit to an existing Brompton and delivers more than enough power assistance.

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