Everything you need to know before you buy an e-bike
So, you’re interested in an e-bike? Great! The humble bicycle has been with us since 1817 when German Baron Karl von Drais invented his Laufmaschine reportedly as an alternative to using horses to get around.
Times have changed, and since then the car, plus other motorized transport, has ruled the roost in terms of getting from A-B in our daily lives. But electric technology is fast developing, and e-bikes are becoming an ever more common sight on our roads, helping people reconnect with the bike and cleaner, healthier transport again.
Here, we’ve put together our definitive guide that aims to demystify the basics of the e-bike, and what you should consider when thinking about investing in one.
Ready? Let’s go.
How do e-bikes work?
E-bikes, also known as pedelecs, are like ordinary pedal-powered bicycles, but with an electric motor and battery fitted that provides assistance, reducing effort, and in lots of cases makes your journey faster.
The keyword here is “assistance”. Unlike e-scooters, which work by engaging a throttle after the initial kick-off, e-bikes offer powered pedal assistance, supplementing the effort that you put in each pedal stroke. This is where the term “electric-assist” comes from.
In the UK, e-bikes are governed by strict laws. The bike must be pedal-powered, while the motor can deliver a maximum of 250W of additional assistance up to a maximum speed of 25km/h (15.5mph), after which it cuts out. For perspective, that’s about the same amount that a well-trained club cyclist might be able to generate for an hour, working as hard as they can using their legs alone.
In recent years, e-bike popularity has grown rapidly. Where once upon a time the only bikes that you’d find with electrical assistance were city bikes, now there’s a diverse market of electric-assist bikes.
Bike riders of all kinds are beginning to go electric, including mountain bikers and road cyclists that prefer to have a little help along the way. As a result, there exists e-road, e-MTB and e-gravel bikes where motors and batteries have been designed into frames that look like traditional enthusiast bikes, as well as those bikes designed specifically for the urban environment.
These ‘city’ e-bikes can come with a standard or step-through frame (so-called “step-through” because of their dipping top tube – or lack of top tube at all – to make getting on it easier). These can also come built with large luggage compartments, which are known as ‘cargo e-bikes’. They all feature flat handlebars and a relaxed seating position compared to enthusiast-type bikes and e-bikes.
However, it’s worth noting that the popular term for these kinds of bikes – ‘city bikes’ – is in fact a bit of a misnomer. These bikes are equally capable of riding in and between rural towns in the country, as they are for a commute or trip to the shops in a built-up area.
Another option is a folding e-bike, pioneered by brands like Brompton. These offer specially-designed motor systems to fit within the smaller, lighter frame, and although these are often less powerful, they offer a great alternative for those needing to take their e-bike with them on public transport, wanting to store it away under a desk at work, or neatly away at home.
Fundamentally, the right type of e-bike for you will largely hinge on what you intend to use it for, for the majority of the time.
Motor types – Frame and hub
E-bike motors come in two main forms – either fitted into the central structure of the frame (known as the bottom bracket area around which the pedals and crank arms spin), or in the hub of one of the wheels. There is no clear winner for which is best – rather, each has its own positives and negatives – but all do a good job.
A frame-mounted motor is the most common in many premium e-bike models, and is arguably ‘smarter’, because it can directly measure how hard you’re actually pedalling with each pedal stroke. As a result, it can provide a set amount of additional assistance based on the effort you’re putting in yourself and the chosen assistance setting (more on that later in ‘Modes’). This ability also means that it doesn’t deliver assistance when it’s not needed, saving battery life in the process.
The downside is that they can require slightly more maintenance than hub motor systems thanks to the added stress placed through the drivetrain.
A hub motor mounted to the rear wheel is attached to the rear hub, where power is transferred through the chain and cassette to the wheel. These types of motors are popular especially in cases where you might not want to show off the fact that you’re benefitting from a motor – like an e-road bike or some especially stylish city e-bikes.
The rear structure of a bike frame is normally the strongest, while the majority of a rider’s weight pushes down through the rear wheel, adding traction. This plays into the hands of a rear hub motor, but the downside is that it can make removing the rear wheel to fix a puncture harder.
Front hub motors are different in that they aren’t directly attached to the pedaling drivetrain, instead of relying on being ‘pushed’ in order to activate and add their own assistance. This sometimes gives the impression that they’re pulling the bike along in response, especially thanks to their position in front of the rider.
More commonly found on cheaper e-bikes, they might also give more equal weight distribution in some models where batteries are mounted in the middle or rearwards, which can improve ride handling.
Battery technology is developing quickly, and in the past few years, some manufacturers have managed to downsize their batteries so that they fit inside the frame itself, or clip into a cavity within the frame. Meanwhile, others are squeezing more and more power out of the tried-and-tested exterior battery design.
Battery dimensions largely depend on its use – for enthusiasts like mountain bikers and road cyclists, a smaller battery that has been wholly or partly integrated into the frame is often desirable for performance and aesthetic reasons. Urban commuters are arguably better served by a more functional, larger design that attaches outside the frame or, as is often the case, into custom pannier racks (these are often cheaper to produce too, without compromising quality).
You may see variations on this theme, but battery capacity should be a top consideration. If you need to complete longer journeys, or you know that you’re going to rely upon pedal assistance more heavily thanks to living in a hilly area, a larger capacity battery (or an e-bike that offers swappable or extendable battery packs) will appeal.
Battery capacity is generally measured in amp-hours, and the higher the number, the bigger its capacity and potential range.
Note: Battery capacities drain over time and use, as well as in very cold conditions (although lithium-ion battery technology, on which the vast majority of e-bike batteries are based, is constantly improving to mitigate this). Look for batteries from reputable companies, and which carry a warranty.
Motor and battery systems combine to work together. Popular and renowned manufacturers from the cycling and electronics industries share this market, sometimes collaborating to develop new systems. These brands include specialists Shimano, Ebikemotion, and Fazua, and more mainstream names like Bosch, Sony, and Yamaha. Remember that electronics and built-in frame mountings for electronic parts are very rarely cross-compatible, so you’ll need to stick with your system once you’ve chosen your e-bike.
E-bike motor systems usually come with a selection of power settings. Arbitrarily, these can be set to low, medium, high, plus some kind of ‘max’ setting, although this varies between motor systems and models. Some may have only two settings, while others might have as many as five or more.
Ultimately, we don’t think that the number of modes should concern you too much – as long as you can easily switch between modes on the go using a control interface, then you can choose what you need when you need it. Experience is the best teacher in terms of knowing what works best for you on a day-to-day basis – many even find that they rarely need to use their e-bike’s ‘max’ setting, instead of using a lower power mode for much of the time.
An e-bike should come with a handlebar or (in some cases) a frame-mounted control unit, while others feature smartphone apps that can offer this, as well as metrics that can tell you your mileage, track your use and even offer tips on how to get better range, as well as run system diagnostics and firmware updates. This control unit (and app) will also indicate how much battery you have left at any given time, while some can dynamically predict what range you have left.
Much like when you drive your car, the e-bike range depends on how you ride it, so claimed ranges by manufacturers should be taken with a pinch of salt. If you ride it in its most powerful mode all the time, then you’ll drain the battery much faster, while hilly terrain will also likely cause the motor to provide more assistance more of the time too, depending on the mode you have it set in.
As we’ve mentioned, some systems feature companion apps that can give you an insight into how to get the most range. But, ultimately, your potential range is a simple equation of your battery capacity, the motor’s power output, and how you ride it.
One of the few downsides of e-bikes is the additional weight the motor, battery, and electronics bring compared to an ordinary bicycle. This means that, although you can ride them with the motor system off, it is more difficult than it would be without those parts.
E-bikes can weigh anywhere from around 10-11kg (for a specialist high-end e-road bike), up to around 25kg in the case of large city e-bikes. In the latter case, this can make carrying them around – onto trains, for example – quite challenging. That said, added weight and ‘sturdiness’ can make navigating potholes and poor road surfaces a bit easier.
Foldable e-bikes, like the Brompton Electric folding bike, stand out because they are designed to be portable thanks to their collapsible design and lower weight (around 16-17kg with the battery attached). However, the smaller wheels and design mean that ride quality is generally not as comfortable for longer journeys.
Build quality and reliability
More established than e-scooters, with more regulations and standards that underpin overall designs, e-bikes can generally be relied upon to provide good standards of build quality (as long as they meet these regulations!) and reliability.
However, there are some pitfalls worth watching out for and avoiding.
Online shopping outlets like eBay are peppered with seemingly fantastic deals on e-bikes, with claims of the same (or even ‘unrestricted) performance and cheaper prices. These should be avoided, as the manufacturers are not necessarily producing or sourcing their frames and components from reputable places, while any warranties given are likely to be limited, at best.
Unbranded e-bikes are also to be treated with caution, as are unbranded motors and batteries. All e-bikes should be capable of being ridden in the rain without issue, but cheap electronics can at best be faulty, and at worst dangerous for obvious reasons.
You may also be tempted into buying second-hand. Although second-hand e-bikes have their place, you risk buying an e-bike that might have hidden, unprovable-until-it’s-too-late issues (such as a degraded battery and/or faulty motor, plus worn-out mechanical parts) that are no longer covered under warranty and need replacing to
Cost and value
Compared to a similarly equipped ordinary bike, e-bikes tend to be more expensive thanks mostly to the inclusion and cost of the motor systems and electronics.
This cost will largely change due to a few factors, which boil down to:
✔ Motor specification ✔ Battery capacity (plus the addition of an extra battery) ✔ Mechanical components (the non-motorized parts) ✔E-bike manufacturer reputation ✔Frame material
However, although e-bikes might seem expensive, often costing several thousands of pounds, it’s important to consider this against the cost of your current commute or travel habits. Do you spend much of that money each year already on public transport, or on fuel and congestion and parking charges for your car, for example?
Often, when totting up the realistic costs of each, an e-bike can work out significantly cheaper than other motorized transport over a period as short as a year, while there are a host of benefits to being outside in the fresh air and staying relatively active too.