The A to B Brompton Buyer’s Guide covers the four key Brompton power-assist conversion kits and Brompton own electric bike. If you’re not interested in a power-assisted Brompton, or any kind of folding e-bike, we have unfortunately had to drop our Buyer’s Guide because there are now so many bikes using a relatively small number of systems, that choosing four or five was getting a bit silly. There’s still a full list of prices and stockists in our comprehensive Electric Bike Price Guide.
Individual entries below include links to our comprehensive road-tests, some still available on real paper, or as downloadable and storable PDFs for 99p or £1.29 per issue depending on the age.
A to B Buyer’s Guide – Top Ten Electric Brompton bikes
1. Cytronex C1
Price: From £1,145 (kit only) Rating: 5/5 Verdict: “Exquisitely designed…”
Cytronex-Brompton
Are we serious? Is a small company in Winchester really turning out the best power-assist system currently available for the Brompton? It’s a subjective thing, and Bromptons get used for all sorts of purposes, but taking into account weight, price, efficiency and user-friendliness, this really is a cracking option, and well worth putting on anyone’s short-list.
For years, Cytronex made a very practical power-assist kit based on the Tongxin motor, still used in the Nano-Brompton. But MD Mark Searles was quietly developing something much more sophisticated, and the C1 was finally launched in 2017 to some acclaim. Before long there was a Brompton variant too. It’s not the cheapest kit-based solution, but nowhere near the most expensive, and it’s probably the most sophisticated, in fact better than many factory-built electric bikes. We have just tried the special C1 T-Type Brompton kit, which is custom-made to fit the new all-titanium Brommie. The complete package, with 198Wh battery, weighs only 11.7kg, which is breathtakingly good… We’ll keep you guessing about the range. Sorry! Well, the digital magazine only costs £1.29.
We have road-tests of the early C1 in A to B 118, fitted to a Brompton in A to B 127 and A to B 132, and to the T-Type Brompton in A to B 136
2. Nano-Brompton 2.1
Price: From £820 (kit only) Rating: 5/5 Verdict: “Now a touch old-tech, but great value…”
Nano-Brompton
For three years after its inception in 2007, the Nano was one of our top recommendations, but it later moved down to a 4-star rating following persistent feedback of battery issues and other quality control problems. For 2012, the Nano returned as Nano 2.0, which has proved lighter, slicker, and more reliable, and was later revised as the 2.1 and back to 5 stars with us. The key change was to Ping batteries, with a promise of a revolutionary fixed price battery repair scheme once outside the 12-month guarantee period, although Nano soon decided it made more sense to source batteries in Europe, and now primarily sells little 144Wh Bosch garden tool batteries. The Nano 2.0 and later variants have the control electronics positioned low down near the front pannier block rather than high up on the handlebars. This looks clumsy if you ride without a front pannier, but you’re unlikely to, because the pannier holds the battery…
Gross weight (including the separate pannier-mounted battery) is a reasonable 15.8 to 18.5kg, and you only have to carry 12.5-14.5kg in one hand. The wide range comes down to the Brompton model used and the size of the battery. The motor is whisper quiet, a capable hill-climber, and managed to go 45 miles on a charge, but this was our first test of a prototype fitted with a large battery and a motor designed for a 26-inch wheel. so it was geared for less than 10mph on a Brompton wheel. That’s a very good way of getting extra mileage! Expect 15-30 miles with a more typical battery and a 15mph top speed.
Early battery issues now seem to be sorted, and there isn’t a great deal else to worry about, although motors occasionally fail. Thanks to Euro-chicanary, most manufacturers have stopped fitting twistgrip throttles, but they are still legal with a pedal movement sensor and Nano offers a twistgrip or thumb-lever as an option. Do take our advice and pay a modest £30 extra for the thumb-lever or twistgrip versions (the nice Nano people can show you how this works). We didn’t like the automatic control one bit, as with most of the cheaper types.
The Nano isn’t quite the discount option it once was, but it’s a reasonable price for a straightforward power kit with a good track-record. The 12-month battery guarantee is looking on the low side these days too, but overall it’s a good little machine, so it stays near the top of our electric bike wish list.
A nice option is factory fitting of the kit for an extra £100… well worth it for the electrically or mechanically challenged.
The Nano kit can be fitted to any bike for a hundred quid less than the Brompton version.
A folding electric bike that still outclasses all but Brompton’s own by a substantial margin.
Full review of the Nano-Brompton. We have also published two follow-up tests (see back issues), a full review of the Nano-Brompton 2.0, and the 2017 spec bike is reviewed in A to B 117
3. ARCC-Brompton
Price: From £1,799 (factory-fitted kit) Rating: 4/5 Verdict: “Hard to fault, but not quite in Cytronex territory…”
An interesting outfit, and an interesting product, if a bit expensive. It’s all good quality stuff, and mostly well engineered, but with a few tedious little niggles like the lack of a light on the control unit and some slightly tricky ergonomics. We said in our test that it feels a bit like a Sunday morning toy rather than a serious tool for commuters, and that sums it up quite well. ARCC has close links with Moulton and is best known for its Moulton kit, which perhaps fits with the enthusiast side of things.
Weight-wise, we’re at the mercy of the particular model chosen by the manufacturers and they tend to choose one with lots of gears and extras, presumably to massage the journalistic ego. Our test bike weighed 17.7kg complete with Bosch 6Ah (216Wh) battery, but ARCC had chosen a 6-speed with an extended steel steat-pillar, so that’s a bit pessimistic. With the tiny 2Ah battery and a lighter bike, you might see 15.6kg, but we found the little battery had a range of barely 7 miles. The 216Wh gives 20 miles, which is OK, but not exactly in Cytronex territory.
The full review of the ARCC-Brompton is in A to B 129.
4. Brompton Electric
Price: From £2,995 (complete bike) Rating: 3/5 Verdict: “A disturbing number of teething troubles.”
Brompton Electric
The factory-made electric Brompton was under development for years, possibly a decade. The problem with that sort of gestation is that the public either lose interest, or the bike ends up featuring a pile of ten-year-old technologies and no-one wants it either way. Both of these things have happened here to some extent, and the development road was to run for another few months after the launch, with a variety of issues surfacing.
What you get is a 2-speed or 6-speed Brompton with crank-mounted torque sensor and Brompton’s own front wheel motor. Weight is from around 17kg (our 6-spd test-bike weighed 17.3kg), but that includes the battery pannier, which weighs 2.9kg, so like the Nano, you should never need to carry the whole lot in one hand – a big advantage.
Very briefly, with bad news first, Brompton’s motor is noisy by modern standards (yes, it would have been OK a decade ago), there are still a variety of software and hardware bugs (dirt on the bag connector is behind most issues), it only comes with one size of battery (unlike the Nano above), and most seriously, you cannot fit a standard Brompton front pannier to the bike, or use the electric front pannier(s) with a normal Brompton… as you can on the Nano, of course. Not the end of the world, but it leaves you with only two options: an impossibly tiny luggage space as standard, or a reasonably capacious bag for an extra £130.
Reliability issues do still occurr unfortunately. There have been motor failures, control-system failures, and for some people just don’t like the pedal torque-sensing system. It’s sensitive to different pedalling styles, so makesure you have a proper ride before buying one.
Early failures like overheating seem to have passed, but there are still some daft practical issues. You can’t easily change power or light settings on the move, because the battery top ‘dashboard’ is too far away, and who decided to make it impossible to fit a normal bag? Were they mad?
The good news is that the electronics are fundamentally well sorted now, as should be with Williams F1 involved, it’s covered by Brompton’s dealer network and warranties (unlike aftermarket options like the Nano and Cytronex), the lights are excellent, power output is good and reasonably controllable (don’t try reaching for the control buttons on the move though), and the price is acceptable.
The bike looks and feels like a product that will last. Not a world-beating design like the original Brompton, but a good solid performer if they can remove all the final niggles. It edged ahead of the Nano in late 2018, but has dropped back since. The choice really depends on your views about bags, cost (Nano can convert your own bike, for example) and warranties.
This really should have been the king of the electric folders, but it’s a bit of a lemon.
We have two reviews of the Brompton Electric – a very detailed early test in A to B 117 from August 2017, and a follow-up looking at the production version (hopefully the definitive version!) in A to B 122 in November 2018
5. Swytch-Brompton
Price: From £1,250 (kit only) Rating: 2/5 Verdict: “A lot of money for a pretty low-tech affair…”
Yes, a bit pricey at £1,250, but the Swytch kits are half price if you are willing to pay upfront before they’ve been shipped or even MADE. Surely one would be a fool to do that? And a fool to pay £1,250? Also true. That price has no basis in the real world, but what brilliant marketing… Price aside, this thing works tolerably well, but you are carrying a big 2kg battery around on the handlebars, which is not the smartest move on a small-wheeled bike. The whole kit weighs 3kg, so expect your finished e-Brompton to weigh 15kg to 18kg according to model. Range came out at 13.6 miles. That’s pretty good and reasonably efficient, but you have to carry a 180Wh battery around on your handlebars to see that sort of mileage.
Our Swytch-Brompton road test is in A to B 120
