Electric bikes (or e-bikes) offer the fun and freedom of riding a bike, with much less of the hard work. What’s not to like about that?

E-bikes allow adults of all ages rediscover the benefits of cycling. Forget the stereotypical image of cyclists: this isn’t Lycra-clad road cyclists or dirty mountain bikers. This is everyday people riding a bike for everyday travel: to get to work, to shop, to meet friends at the café.

Anyone who doesn’t ride a bike usually has a few reasons why. Safety on the roads is the top concern – if you haven’t ridden since you wore a school uniform, some of our roads can look pretty dangerous. However, many people also think they aren’t fit enough – no-one wants to arrive at their destination sweaty and out of breath. Hilly terrain and headwinds also put people off riding. Bikes can’t carry much of a load. And the weather is never quite good enough. An e-bike’s power-assistance removes most of these obstacles. Unfortunately, it can’t improve the weather.

Accelerating gently into the future

E-bikes make cycling more accessible to more people. They overcome any lack of fitness, make loads easier to carry, flatten out hills, negate headwinds and extend the distance a cyclist can cover. If you’ve considered riding a bike to improve your health and wellbeing, but have been put off by any of these reasons, the e-bike is your solution.

There’s positive news for safety too – the main reason given for not riding a bike. Research shows more people cycling improves the safety of every cyclist (it’s a “safety in numbers” effect). With more people cycling, councils and government will find more reasons to invest in cycling. Which, in turn, will encourage even more people to cycle.

In addition to the economic, environmental and health benefits, perhaps the best reason to jump on the e-bike bandwagon is that riding one is such good fun. You might even find yourself going for a ride just for the joy of it.

Anatomy of an e-bike

At the centre of any e-bike is a normal bicycle. But an e-bike also has an electric motor, battery and an electronic control system to make life easier for the rider.

Motors are usually mounted at the centre of the rear wheel in a hub drive, or down by the pedals in a mid-drive. Hub-drive motors can be retrofitted to nearly all existing bikes, so are more common, particularly on less-expensive e-bikes. But mid-drive motors that drive through the bike’s gears, such as the Bosch system, have a performance advantage – they make better use of the assistance available.

Batteries are lithium-ion. They recharge from flat in less than four hours, and are good for 500 to 1000 recharge cycles before starting to lose capacity – that’s likely to be at least three to six years of use. Once they lose capacity, they still work but with a reduced range. Replacement batteries are readily available, costing upwards of $600 depending on brand and capacity.

Motor controllers are the really clever bit. They use sensors to measure how fast you are travelling and pedalling. Some also measure how hard you’re pushing the pedals. The measurements are used to adjust the level of motor assistance – you get less help when cruising quickly, and more when pushing hard on the pedals riding slowly. If you aren’t pedalling, the bike works just like a normal, unpowered bike. A control on the handlebar allows the rider to select their level of assistance. Our regulations also allow for a hand throttle so the rider can manually boost motor assistance.

An e-bike rider can expect from 30km to more than 100km from a full charge –depending on battery capacity, weight of the rider and load, terrain, wind, and how much pedalling effort the rider puts in.

The quality of batteries and controller generally increases with e-bike price. At the top end, Bosch guarantees its batteries for 500 charge cycles (or two years). Even if worked extremely hard, that’s at least 15000km of riding. More advanced controllers respond faster to rider inputs, deliver power smoother and have features such as walk-assistance.

Most e-bikes also have lights powered from the battery. Many also have USB ports for recharging mobile devices.

A primer on e-bike styles

Just like normal, unpowered bikes, e-bikes come in various shapes and sizes, each better suited to different sorts of riding. However, bikes are versatile; most perform fine in most situations. Broadly, e-bikes can be split into these categories:

  • City bikes, sometimes known as “Dutch bikes”, are designed for short urban rides. They are relatively heavy – 18kg or more without the motor and battery – and often have step-through frames, swept-back handlebars, a plush seat, full mudguards and cargo racks or baskets. They might have up to 10 gears or an automatic gear system built into the rear hub. They aren’t built to go fast, cover long distances, or slog up hills. But they are comfy and can carry lots of luggage or shopping. A variation is a cargo bike, which has a longer wheelbase to accommodate additional load-carrying space either behind the seat or in front of the handlebars.

  • Recreational, hybrid or commuter bikes are the do-everything bike, covering a wide variety of riding from daily commuting, to weekend rides on rail trails, to longer “fitness” rides. With flat handlebars, narrower tyres, up to 30 gears and a racier riding position, they are faster and are more comfortable than city bikes, including up hills. However, they are less manoeuvrable on city streets and not so well equipped for carrying luggage or shopping, though many at least have mudguards and a cargo rack.

  • Trail or mountain bikes, are designed for riding off-road on rough terrain. They have suspension at the front (and sometimes at the rear too), wide flat or high-rise handlebars, wide knobbly tyres and up to 30 gears. They are often repurposed as an urban or commuter bike, as they are tough, have a big range of gears, powerful brakes, and offer a balance between city-bike comfort and recreational-bike speed.

  • Folding bikes are designed to, well, fold. That’s useful if you regularly take your bike on a train, ferry or bus, or if you need to store your bike inside your home or office. They have smaller wheels to aid folding, but otherwise ride like a recreational bike. There aren’t too many electric folding bike designs as the additional weight of a motor and battery makes them harder to carry.

Buying an e-bike

Our e-bike market is maturing quickly. Only a couple of years ago, e-bikes here were the preserve of DIY tinkerers, or were low-quality, imported from China and sold through Trade Me. E-bikes like that are still available – and best avoided. The new generation, including models from European specialists with Bosch and Yamaha motors, aren’t cheap, but they have vastly superior quality and, as sales increase, prices will come down.

The minimum you should expect to pay for an e-bike is about $2500. Paying $3000 or more gets a better quality bike, battery, motor and controller. Upwards of $5000 buys an e-bike from a European e-bike specialist or large traditional bicycle brand.

You also need to include $150 to $200 for a helmet and a good quality bike lock. You might also want to consider insurance. Adding an e-bike on to a home contents policy is the most cost-effective option. You need to specify the bike as an extra on the policy and maintain proof of value, but insurance shouldn’t cost more than a few percent of the bike cost. Check your policy covers your bike when locked in a public place, not just when stored at home, and includes third-party cover when riding.

To put the purchase costs of an e-bike into context: in Wellington, if your car was parked in a public garage, with a typical “earlybird” all-day rate of $15, you’d pay the equivalent of a $3000 e-bike in 200 days – just one year of weekday parking. Alternatively, your e-bike wouldn’t cost anything to park.

A snapshot of e-bikes in NZ

Smartmotion

$2100-3600. smartmotionbikes.co.nz or electricbikes.co.nz.
Smartmotion is a New Zealand company who designed the e-bikes used by New Zealand Post. Its range of folding, city and hybrid bikes, manufactured in China, is available with either a front- or rear-wheel motor and battery mounted on a rear cargo rack.

eZee Kinetic

$2500-4000. ezeebike.com or electricbikehub.co.nz.
eZee Kinetic is a Chinese company who have been in the e-bike business for more than a decade. It offers a range of folding, city, hybrid and cargo bike styles, with rear- or front-wheel hub motors and a battery distinctively mounted behind the seat.

Linus with Lekkie kit

$2850 (kit-only $1790). bicyclejunction.co.nz or lekkie.bike.
Assembled by Wellington store Bicycle Junction, using US-designed and Taiwan-made Linus bikes and the New Zealand-designed Lekkie electric drive kit. The two urban bikes available have a choice of either a mid-drive or rear-hub motor and battery mounted to the frame.

Pedego

$2900-3700. pedegoelectricbikes.com or electricbikes.co.nz.
Pedego is a US company with a range of city, hybrid and beach cruiser bikes made in China. They have rear-hub motors and batteries mounted to the rear cargo rack.

Moustache

$4950–8950. moustachebikes.com or ebikestudio.co.nz.
Designed and manufactured in France, Moustache bikes use a Bosch mid-drive motor with a battery either integrated into the frame or mounted on the rear cargo rack. Its range includes city, hybrid and mountain bikes.

Haibike

$4500–7200. haibike.de or e-motion.co.nz.
Haibike designs and manufactures its bikes in Germany. Its range of hybrid and mountain bikes uses Bosch and Yamaha mid-drive motors and batteries integrated into the frame.

Specialized

$5500. specialized.com.
This large US-based bicycle company manufacture in Taiwan. Its hybrid e-bike uses a Specialized-branded rear-wheel motor and battery integrated into the frame.

Not quite a free ride

It’s doubtful an e-bike would totally replace your car. A car would still be necessary on wet and cold days and for times like the weekly grocery shop. But the cost savings of using the e-bike are compelling and the bike might mean you don’t need a second family car, even if you don’t ride every day:

For a 20km commute (10km each way) in Wellington:

  • Electricity cost for an e-bike: $0.06 per day (40km per charge from a 400Wh battery, with electricity at 26¢/kWh).
  • Petrol cost for a small car: $1.80 per day (at an admirable 5L per 100km, with petrol at current prices).
  • Bus fare: $7.26 per day (for a three-zone trip, using Snapper payment).

You need to factor in battery replacement into running cost calculations – rechargeable batteries don’t last forever. However, an e-bike battery should last for 500 to 1000 charge cycles (or 20000 to 40000km of riding) before losing capacity. That’s likely to be 4 to 6 years. Once capacity reduces, the battery is still usable but the bike’s range reduces. A top- end Bosch battery costs US$900 ($1400), while a Lekkie battery, using good quality Samsung cells, can be bought for half that price.

Just like a normal bike, an e-bike needs servicing and new parts over its life such as tyres, a chain, and brake pads. An annual service at a bike shop, including parts, should cost no more than $200.

Being classed as a “power-assisted cycle” means your e-bike won’t need an WOF or attract any registration costs.

Power to the people

You’ll still need to pedal an e-bike, but set to give maximum power-assistance, your hard pedalling efforts would only be needed to accelerate quickly or to climb a big hill. Alternatively, if you used a lower power-assistance setting, you’d need to put more effort in, but you’d still be able to tackle bigger hills and you’d travel much faster than you would on a normal bike.

Travelling at a steady speed on any type of bike, you have to overcome rolling resistance (which doesn’t change much with speed) and air drag (which increases dramatically with speed). At some point during a ride, you’ll also need to speed up and to climb hills.

If you want to ride fast, it is best to get into an uncomfortably low, aerodynamic position and hope for a tailwind. To accelerate quickly and fly up gradients, you and your bike should be as light as possible.

How fast and how far you can ride, and the size of hills and headwinds you can tackle depends on your power output. For a normal bike, power comes from just the rider. For an e-bike, power comes from both the rider and the motor.

Power is measured in Watts – it is the rate of energy conversion. For a cyclist that’s potential energy from food being converted into kinetic energy of motion (and a bit of heat). For the motor, the potential energy is stored in the battery, and the motor converts it to kinetic energy and heat. Power can also be viewed as a force multiplied by speed. On a bike, your power output is how hard you can push on the pedals (force) multiplied by how fast you are turning the pedals (speed).

So how does an e-bike motor with a continuous output of 300W compare to the power needed to move a bike and rider?

If you and your bike weighed 85kg, moving at a constant 20km/h on level ground with no wind, you would use approximately 105W. With a light 10km/h headwind or a gently graded 1 percent hill, power required to maintain that speed increases to approximately 160W.

If you were a physically able but untrained cyclist, you could sustain an output of about 200W for 5 minutes. That’s at maximum effort and working up a real sweat. If you eased off the pedals, you could maintain more like 100W over an hour. That’s about the same as the power needed to move at a constant 20km/h on level ground with no wind. Riding into a stronger headwind, climbing bigger hills, or carrying a load, would mean you’d need to slow down. Or get fitter. If the headwind was too strong, or the hills too steep, you’d be off and pushing your bike.

The extra power-assistance from the e-bike motor can make a big difference. At one extreme, with up to 300W available, your journey would be much easier. Alternatively, if you wanted to get the same level of physical workout, you could lower the power-assistance, but you’d still travel further and faster than on a standard bicycle.

To place those power outputs in context, here’s a video of track cyclist Robert Förtstemann and his 73cm circumference thighs powering a 700W toaster for one minute.