We've independently tested folding electric bikes from brands such as Brompton, Raleigh and GoCycle, so that you can find the best option for you, and avoid spending too much on a dud.
Our reviews answer the most crucial questions about folding electric bikes:
A good folding electric bike should be practical for carrying around and storing in a compact space or transporting by car, caravan or train. The motor and battery system should also be capable of providing adequate support on inclines or over longer distances. It also needs to get the basics right, providing a smooth ride and standing up to regular use and transportation.
In our tests, we found that some bikes were unwieldy to carry, with some unfolding as you go. Others were jerky to ride, or had poor-quality hinges that wouldn't stand up to regular use.
Our reviews are independent. We buy all the products we test ourselves, and don't accept freebies from manufacturers of retailers. So you can be confident that the only thing that influences our recommendations are the test results we get from our labs.
We base our tests on how you use products in real life, focusing on the things that matter the most. All our tests are conducted under exactly the same conditions, so when you look at our results you can be sure that all of the folding e-bikes were tested on an equal footing and that scores and ratings are directly comparable.
We also buy the products we test anonymously from retailers, just like you would, so that we get an authentic product straight off the shelf.
There are big differences between bikes in the distance that they can be ridden on a single charge. Range figures from manufacturers aren't comparable because the testing conditions, such as the weight of the rider, rolling resistance and wind resistance could all be different.
We test under exactly the same conditions, down to controlling the humidity and temperature of the lab. That way we can provide accurate and comparable range figures based on riding the bike on a variety of settings and on different terrain.
Some electric bikes can't even maintain the bike at 11mph on a 6% gradient, so won't be particularly suitable if you live in a hilly area.
We also test the bike motor's efficiency and how it performs on both the minimum and maximum settings.
After taking some time getting to know how each bike folds, we measure how long it takes on average to unfold the bike and also to fold it back up.
We also measure the volume of the bike when its folded. Some take up twice as much space as others and are therefore completely unsuitable for commuting on a busy train service, or putting in the boot of a small or medium car.
Others are hard to carry, and even start to come unfolded as you go. Weight is crucial here. Some folding e-bikes weigh more than a standard bike, which can make lugging them around impractical unless you're a champion weightlifter.
We also assess how easy it is to remove the battery so it's easier to carry the bike, and whether you can remove it if you want to store or charge the battery separately from the bike.
Ultimately, you want your bike to be pleasant to ride, otherwise your commitment to the pedals is likely to wane swiftly. It should be smooth and comfortable, evening out the jolts from bumpy roads and seamlessly providing motor support when needed. There should also be scope for adjustment to suit your measurements.
We test how well the motor helps you off the line; some take a few pedal strokes for the power to kick in, but the best provide support almost immediately. We also assess how well each bike takes corners at low speed, such as going around a small roundabout. Vibration is assessed when riding over cobbled and gravel roads, and we check how noisy the motor is, too.
We also test how quickly the electric motor responds to you applying the brakes and stopping pedaling. Some motors are slower to respond than others, which could affect your braking distance.
Finally, we make an assessment on the quality of the control unit and how easy it is to increase or decrease motor assistance levels while you're riding.
If you're investing thousands of pounds in an electric bike, you'd expect it to last. And folding bikes are likely to take more knocks and scrapes than your average bike, as you will be regularly folding, unfolding and transporting them, so if the bike has poor hinges or doesn't sit well, it's likely to get more battered over time.
We assess everything from the stiffness of the frame at the front and rear of the bike to the quality of each folding hinge. The quality of the seat adjustment lock and any adjustments possible on the steering tube are also checked.
We were really unimpressed by the poor build quality of some folding e-bikes. This was an area where the difference between best and worst models was very clear. Models with poor hinges are unlikely to stand the test of time, as they're flimsy and prone to rust. We've also found some hinges that are incredibly fiddly to tighten and loosen.
All of the assessments listed above go into making the final overall score for each folding electric bike we review. Some elements are more important than others, based on what's most important to you when buying a folding e-bike. The score breaks down as:
A model has to achieve 80% of more to earn our Best Buy recommendation, and anything scoring below 45% is highlighted as a Don't Buy that we think you should avoid.
Lithium-ion batteries always deplete and eventually die over time, and at Which?, we believe that products should last longer than the batteries they come with. That's why we will not give electric bikes Best Buys if spare batteries cannot be bought from the manufacturer – no matter how good they might be.