The term folding e-bike encompasses a wide variety of designs. As is obvious from the name, they all fold in one manner or another, usually through hinges or pivots manufactured into the frame; but the reason for the fold and the overall design of the bike can vary greatly. Before we dive into the design details, let’s consider who might want one...
Regular visitors to London can’t have missed the explosion in folding bikes that has taken place over the last few decades. Indeed for many thousands of commuters around the world, folding bikes and e-bikes have made ‘multi-modal travel’ the most practical way of getting to work, and it’s easier than ever to find a folder that you can take on most types of public transport. Light weight and quick-folding qualities are usually at a premium to allow you to get your machine on and off the train as quickly and easily as possible.
Smaller, lighter folders will also appeal to those who want a bike they can keep inside their house, especially if space inside is limited. This may be because of concern about theft, or perhaps because of a lack of useable outside space. Here, the lightness and portability of a folder pays dividends, especially for those who need to carry it up steps or store it when inside.
The leisure market is another huge target for folding e-bike makers, but here we can assume that folding isn’t something that needs to be done multiple times a week. A reasonably compact fold, a light weight comfortable ride and an attractive price tag are the more typical attributes of your more leisure-orientated, ‘campervan’ e-folder.
A rarer category could be classed as e-folders for utility and touring. Here bigger batteries, bigger wheels and increased carrying capacity compared to other e-folders are all important. They can take more weight longer distances, but still fold to allow them to be used with other transport links in your journey. Sturdier models can cope with child seats and quite large cargo loads.
So to summarise, some e-folders are built to fold as small as possible and be as light as possible, while others aim to replicate some of the characteristics of bigger e-bikes like a comfortable, predictable ride and larger battery capacity. Delving into the different design aspects of e-folders, as we do below, it soon becomes apparent any e-folder is a trade-off between these characteristics.
Wheel size and gearing
There are two main ‘families’ of wheel sizes on folders and electric folders, grouped by the approximate diameter of the wheel plus the tyre: 16” and 20”. 16” wheels are chosen to make for a more compact fold and to cut weight, with the downsides being extra rolling resistance of a more sharply-curved tyre (compared to larger tyres of an equivalent design) and rather more sensitive handling than bigger versions. Conversely, folders with 20” wheels mean a larger and usually heavier folded package, but they may produce a more efficient, comfortable and predictable ride. For carrying on public transport, you might find 20” wheels more of a struggle to get on a train luggage rack, to give one example.
As with most other bike types, there is a choice between derailleur gearing and hub gears. Derailleurs are lighter but need more maintenance, and can be more prone to damage (an even greater risk for folders jammed on luggage racks on a busy train). Hub gears are heavier, but lower maintenance and more intuitive to use.
Small wheelers are easier to pedal up to speed quickly compared to larger ones, but less efficient at maintaining speed over longer distances, pedalling steady at a consistent pace. This is another reason they are so popular as ‘start/stop’ machines for nipping through city traffic.
Frame and folding mechanism
The most common type of folder is the ‘fold in half’, where the frame hinges in the middle and the seatpost and handlebar post fold down. This is pretty quick and easy, but often results in a bigger folded package than other designs.
The main other type of design is one that breaks the frame in two places. By its very nature this is a little more complicated to fold, but generally produces a smaller package than a ‘bi-fold’. The Brompton is the classic example of this and the quick, compact and secure fold is an absolute classic of bike design. The electric version retains the same superb folding mechanism.
Unlike on larger e-bikes where mid-drives are becoming dominant (particularly when you move above the £1,500 price point), hub motors are by far the most common on folders. That’s simply because these can be made lighter than most mid-drives, and are less likely to get in the way of the fold. Batteries are often smaller in capacity too, to keep weight down and help simplify the fold. The battery sizes on our recommended selection of e-folders are pretty typical, ranging from 150Wh up to 400Wh. On full size e-bikes a typical range is 300-625Wh, with options for dual battery systems meaning 1250Wh is possible. Of course you can always buy a spare battery for an e-folder and carry it with you to extend your range.
7 of the best folding e-bikes
Here is a selection of e-folders we'd recommend that fulfill some or all of the criteria mentioned above depending on what you want out of a folding e-bike. Where possible we've tried to list bikes we can fully recommend, backed up with a full review from an eBikeTips tester...
The Stow-E-Way is a capable folder with a 245Wh battery and a good quality electric assist system, from a well-respected manufacturer called Tranz-X. It delivers smooth, strong power and comes well equipped with LED lights, mudguards and kickstand. The rack is frame integrated and very strong. Although the folded package is a little bulky with its 20” wheel design, it does fold fast and is easy to cart around. Like the B’Twin featured below, the Raleigh Stow-E-Way comes with a two year guarantee on the electrical system including battery and backup from a major retail chain.
Read our review of the Raleigh Stow-E-Way here
Of all the e-folders featured here, the Vektron Q9 is the one that brings the most full-size e-bike qualities to the table. It is the only one with a mid-drive, in this case courtesy of Bosch, making it the most powerful e-folder here. It also has the largest battery, which is 400Wh, frame-mounted and removable.
It’s a hugely capable load carrier too, as our review makes clear, having space on the rear rack for a YEPP child seat and a pair of sizeable panniers, just to give a couple of examples. The downside means it’s the heaviest bike on our list (21.9kg), and quite a bulky package when folded at 41cm x 86cm x 68cm. That said, it can be tipped onto its rear end when folded to store it vertically, and with the seatpost extended it can be rolled around station platforms with relative ease.
Read our review of the Tern Vektron Q9 here
The GoCycle GX gets full marks for both practicality and style, with its smooth, funky looks meaning it has been dubbed ‘the iPhone of e-bikes’. It was designed pretty much from the ground up by UK designer Richard Thorpe, and features proprietary technology such as ‘Pitstop’ mag wheels on single-sided forks (that pop off easily in the event of a puncture) and a tiny yet powerful front hub motor.
While at 18.7kg it’s not the smallest or lightest folded package, it’s still pretty impressive for a 20” wheel machine. It would make a practical train commuting bike (as long as you don’t need to lift it above your head too often) as the folded package can be easily wheeled across a platform, and it’s nice and stable when sat on the ground. The fully enclosed transmission and hydraulic brakes make it very low maintenance too. Optional accessories include front and rear carrying racks and full lighting kit; although these bespoke items add considerably to the cost.
Read our review of the GoCycle GX here
This is one of the few true budget choices that offers a really decent level of quality compared to the pricier options out there. It has a fold-in-half aluminium frame and frame-enclosed 187Wh battery, rear hub motor and six derailleur gears, and weighs in at 18.6kg. Budget aspects of the system include crank motion-sensing power activation, as opposed to a more sophisticated torque-sensing system. The folded size is 83cm x 67cm x 45cm, and it rolls on 16” wheels. There’s a full range of accessories too, including LED lights, mudguards and a kickstand.
The Hummingbird Electric combines a super light weight folding e-bike with an all-in-one Zehus hub motor, for a bike that weighs just 10.9kg in total. With 16” wheels, the folded size is 115cm x 63cm x 20cm. If you really must have an ultra light e-folder and are willing to pay very good money for it, then this should be top of your list.
The two piece fold means the rear alloy spaceframe swings under the main carbon fibre body element. The bars drop down at the side to produce a long, slim and quite portable package that is securely locked together. It does come with some performance limitations that are part of the trade-off for such simplicity and lightness. The combination of a gearless motor and single-speed transmission mean it isn’t the greatest hill climber. Regenerative braking feels nice and technologically advanced but will never add much power back into the battery on a lightweight e-bike. Still, it’s wonderfully fast, stiff and responsive to ride and very few e-folders come anywhere near it on the scales.
Read our review of the Hummingbird Electric
The electrified version of the classic Brompton keeps the legendary quick and compact fold, and combines it with a powerful front hub motor and removable battery pack. This can be combined with luggage storage sitting at the front of the frame, where the traditional luggage mounting block sits on the non-powered version. It comes with 16” wheels and a 312Wh battery, and there are 2 speed and 6 speed versions available.
Brompton is of course the train and bike commute folder par excellence and Brompton’s own motor system is powerful and responsive, if not the lightest out there. The Brompton Electric is fairly heavy in comparison to some third party conversions designed specifically to convert unpowered Bromptons into electric versions; most notable amongst these is the Cytronex Brompton kit.
Read our review of the Brompton ML6 Electric here
The MiRider One has an unusual design, with a magnesium frame and the option of throttle control (though to remain legal, pedals must also be turning at the same time). It’s single speed so only really at home over more moderate hills, but more aimed at motorhomers and leisure riders. That said, it would also be equally useful employing the throttle control to buzz around the city. With 16” wheels and a 187Wh frame-integrated battery, the One has folded dimensions of 67cm x 66cm x 43cm.
There is even better news for the future from MiRider; they are working on retrofittable upgrades to reduce the 18.9kg weight and increase power, including a torque sensing bottom bracket mated to a lighter but more powerful rear hub motor. The main weight-saving elements are lightweight wire spoked wheels, sports tyres, carbon fibre seat, stem and handle bars. A larger capacity battery is also in the pipeline too. Watch this space...
Read our review of the MiRider One here