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Electric Bike Buyers’ Guide

Electric Bike
(Image credit: Unknown)

The basics of an electric bike are the same across all brands and types. A motor, powered by a battery, provides assistance to the rider as they turn the pedals up to a speed of 25km/h, when the assistance has to cut out by law. This means you can ride them without any fear of breaking a sweat or having to climb out of the saddle and walk, shamefaced, up a hill (it’s happened to the best of us).

Beyond the basics, however, there is plenty of variation in the e-bikes available today. So to get a better understanding of the options and how they affect your ride, we spoke to James Olsen, head of own brand development for Evans Cycles (opens in new tab), who is part of the design team behind the bike shop’s Pinnacle range of regular and electric bikes, and Peter Hunt, an e-bikes expert at Halfords (opens in new tab).

What’s the best battery position on an e-bike?

Almost all e-bikes opt to put the battery in the middle of the bike, just above the pedals, or on a rack on top of the rear wheel. Each option has its own advantages.

“The reason we put the battery in the middle is because weight distribution is important,” says Olsen.

“By putting the battery, which is a big part of the weight of an e-bike, close to the centre and low down you end up with a bike that feels a bit more natural to ride.

“Putting the battery up on the rack on the rear can have advantages, in that you can have a step-through frame because the battery is right out of the way.”

Who are the main motor manufacturers? And which is the best?

Two names crop up a lot when you look into e-bikes: Bosch and Shimano. Both produce motors that are used by many other brands.

“Bosch is the clear market leader at the moment,” says Olsen.

“It got into the e-bike market early on and it’s got electronics expertise. Shimano makes a very good unit as well. We use the Shimano mainly because the customer support from Shimano is very good – not to say that Bosch’s isn’t.”

What’s the best position for the motor on an e-bike?

“Front drive motors are the cheapest and drive power through the front wheel hub, but these can make accelerating out of corners a little precarious,” says Hunt.

“Rear hub motors put the weight at the rear and provide better traction and more stability. Central drive motors are quickly becoming the most popular system, because they make an e-bike ride much more like a regular bike and keep weight near to the bottom bracket, providing optimum stability, which is hugely important for city bikes as well as mountain bikes.”

What is the difference between a speed sensor and a torque sensor on an e-bike?

On cheaper e-bikes the assistance sometimes arrives with a jerk, while more expensive models offer a smoother experience, especially at low speeds. This is more or less down to whether a speed or torque sensor is used.

“Speed sensors feature on cheaper e-bikes and generally provide an ‘on or off’ feel to the motor,” says Hunt. “Torque sensors are more sophisticated and make a huge difference to the ride quality because they provide power relative to the rider’s input, making an e-bike feel more like a regular bike and allowing for more controlled cornering and low-speed manoeuvres.”

Are there any key specs to look out for in a motor and battery?

The power of the motor and the size of the battery both feed into the most important selling point of an e-bike – how many miles it’s going to cover without running out of juice.

“What it comes down to is range,” says Olsen. “Range anxiety is a big thing with e-bikes – people don’t want to be stranded with a flat battery.

“But it’s a really open-ended question. There's a certain amount of power in the battery, but how heavy the bike is, how heavy the rider is, the power setting they are using – all these things matter. It’s like how far you get on a tank of fuel depends on how you drive your car.”

“Generally the battery size will tell you how much capacity you’ve got. That’s the main thing – how many watt hours you have on a battery.”

The overall range of an e-bike fluctuates depending on the amount of assistance you demand from it. Most will have three or four settings running, from an eco mode where you get less assistance but the maximum range available, to a top setting that provides lots of power but will normally cut the range in half.

“As a rough guide most systems will get 50, possibly 60 miles [80-96km],” says Olsen.

“The official stats will tend to be a little bit higher, but like the official fuel efficiency stats for cars, that’s only in the perfect scenario.”

Folding e-bikes and ones designed for short commutes might also sacrifice some range for a smaller battery that weighs less.

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“You want to carry a folding bike,” says Olsen. “If you have a big battery it increases the weight of the bike you've got to carry, and they tend to be ridden not more than four or five miles in any one journey.”

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How much maintenance does an e-bike require?

“As with any rechargeable battery you’re going to have a limited number of charges and discharges before the battery stops holding capacity in the same way,” says Olsen.

“It’s like your mobile phone or laptop – a couple of years down the line they don’t hold the charge as well. E-bikes are the same.”

“As with any rechargeable battery you’re going to have a limited number of charges and discharges before the battery stops holding capacity in the same way,” says Olsen.

“It’s like your mobile phone or laptop – a couple of years down the line they don’t hold the charge as well. E-bikes are the same.”

But you can do things that will help to wring the most out of your e-bike’s battery.

“Always store your e-bike charged,” says Hunt. “Leaving a battery over winter or storing without charge can lead to your battery entering into a deep-sleep mode, which requires a special deep-charge through a registered service centre to restore it to life. In the long term, this can also degrade the battery and affect its future performance potential. Always store your e-bike with at least a 60% charge and recharge every six weeks when not in use.

“Where possible, charge and store your battery in a warm environment. Batteries hate the cold and if you charge it indoors, the battery will accept more charge. Likewise, if you fit a battery that has been kept indoors to your bike, its range will be longer and its performance superior.”

However, beyond keeping an eye on the health of your battery, which might need to be replaced every few years, there isn’t any more maintenance required on an e-bike than on a regular bike, since you really shouldn’t start fiddling with the motor.

“The power system on an e-bike is not user-serviceable,” says Olsen.

“You plug it in, charge it up and use it like a normal bike. There’s no extra service or maintenance needs. If there’s any problems with the electrical components it will be taken care of by the warranty.”

Is commuting the main use for e-bikes?

Electric bikes are an excellent way to get to the office without requiring a change of clothes while avoiding the crush and potential delays of public transport. However, according to Olsen, they are at least as popular for mountain biking, if not more.

“Mountain biking tends to be quite a social activity,” says Olsen, “and fitness can make a massive difference to how well a group can stick together on a ride.

“A lot of people go downhill happily at their own pace, but climbing is when differences in fitness really show up. I see a lot more people buying mountain e-bikes so they can keep up with fitter riders.”

Touring on e-bikes is yet to really take off in the UK, but it is a common sight in parts of the continent.

“If you go to the Rhine Valley in Germany you see a lot of group tours along fairly flat countryside using e-bikes,” says Olsen.

How much do you need to spend on an e-bike?

You can get a decent commuting e-bike or folding e-bike for around £1,000, but generally you need to spend more like £1,500 to £2,000 to get a quality hybrid bike, and probably over £3,000 for a dedicated road or mountain e-bike.

If you spend extra money on an e-bike you’re likely to be rewarded with useful extra features like integrated lights powered by the battery, automatic electronic gear shifting or the ability to customise the assistance provided by the motor. If you opt for a full-suspension mountain e-bike, that will also increase the cost.

Another trend in more expensive e-bikes is that the frames are custom-built to integrate the battery and motor, rather than the designer adding the parts onto an existing frame.

“The easiest way for a manufacturer like us is to take a proven system like Bosch or Shimano and add it to a proven bike format,” says Olsen.

“With some of the more expensive options, on the other hand, they are creating frames that are designed to house a custom-made battery so the whole thing is hidden, more integrated. It’s a much more expensive engineering process to do that, but it’s becoming more popular.”

Nick Harris-Fry
Nick Harris-Fry

Nick Harris-Fry is a journalist who has been covering health and fitness since 2015. Nick is an avid runner, covering 70-110km a week, which gives him ample opportunity to test a wide range of running shoes and running gear. He is also the chief tester for fitness trackers and running watches, treadmills and exercise bikes, and workout headphones.