E-bike conversion kits: How to add an electric motor to a regular bike

E-bikes [1] have made cycling more accessible than ever before, helping to broaden horizons and open up a wider scope of riding opportunities. All of this has been achieved through their motors which provide assistance during a ride, taking up some of the slack. This can be great for those who don't have the fitness levels to ride mechanical bikes, want to enjoy more relaxed rides, or want to find a greener alternative to driving [2].

All of this has combined to make e-bikes hugely popular and the industry is in the midst of a boom [3].

Despite this, electric bikes still remain inaccessible to some courtesy of their higher price tags. While there are budget-friendly options available, e-bikes are generally more expensive than their mechanical cousins. Luckily, there is another option.

Rather than buying a new e-bike [4], it is possible to turn a standard mechanical bike into one through an e-bike conversion kit.

It's an option that many cyclists are now taking advantage of, but what is an e-bike conversion kit and how do they work? Here's everything you need to know.

Explore all of our e-bike buying advice and guides [5]

What does an e-bike conversion kit contain?

E-bike conversion kits come in all different shapes and sizes (more on this later), but they all contain the key components needed to electrify a standard mechanical bike.

This includes:

Motor: The motor is what provides the assistance. There are many different types available, from mid-drive to hub-based.
Battery: A motor can't power itself, which is where a battery enters the equation.

Pay careful attention to the capacity of a battery, as this will influence the range of the e-bike system. The larger the capacity, the more assistance you'll get between charges.
Computer/control system: The assistance level on an e-bike can be varied depending on your needs, usually through a device or computer mounted on the handlebars.
Sensors: Completing the set-up, sensors are important. These are used to detect how fast you are going, which is important if you're to abide by laws, and how hard you are pedalling.

The latter ensures you receive the right amount of assistance.
Charger: The battery will need topping up, which requires a charger.

Types of e-bike conversion kits

Not that long ago, the e-bike market was still in its infancy. Anyone wanting to electrify their ride had a narrow selection of bikes. Things couldn't be more different now, and the e-bike market is a bewildering place to navigate [7].

From folding and cargo, to road and mountain bike, there is an e-bike available for virtually every type of riding.

The same can be said for e-bike conversion kits, which have mimicked the availability of regular e-bikes. So, no matter what type of mechanical bike you have, there's a good chance that there will be a compatible conversion kit available. This compatibility is key, as you don't want to invest in something that won't work.

Make sure that you have a compatible kit before pulling the trigger and buying one.

E-bike systems also come in varying forms.

Mid-drive motor

Common on regular e-bikes, mid-drive motors are also regularly used in e-bike conversion kits.

For this set-up, the motor is mounted around the bottom bracket, near the pedals. This has the advantage of keeping the weight low down, creating added stability.

Hub motors

Hub motors provide the most practical option. These are built into wheels, and are usually powered by a separate battery.

They're the easiest option as you simply swap out your wheel and are also commonly used for converting folding e-bikes, where the real estate for a mid-drive motor is limited to non-existent.

Integrated motors

For a cleaner aesthetic, you may want an integrated motor that is hidden from sight.

These are uncommon due to the difficulty of fitting such a system to a bike - remember, mechanical bikes aren't specifically designed for e-bike systems. So, it's best to stick to one of the other options.

Will an e-bike conversion kit damage my bike?

Conversion kits are specially designed for mechanical bikes, so you shouldn't run into many problems - but still proceed with caution.

Read your owner's manual to ensure you're not doing anything that will void the warranty or inadvertently cause damage.

E-bikes often also use special drivetrains that are designed to handle the additional torque of the motor. Your mechanical bike won't have these specialised components, which could cause extra wear and tear, leading to mechanical problems.

Benefits of e-bike conversion kits

E-bike conversion kits have one major benefit over a regular e-bike: cost.

Rather than having to splurge big sums on a shiny new e-bike, you can instead convert your existing steed.

Doing so will be much more cost friendly, with many conversion kits coming in at under GBP500 / £500 - in comparison, e-bikes often carry heftier four-figure sums.

Using an existing bike is also more convenient too, although you may be questioning that when you're trying to set up the system on your bike. Depending on your practical skills, this can vary from relatively easy to a pain.

Then there's the prospects for future upgrades. As it isn't a permanent fixture, conversion kits can be removed from a bike to make way for a newer model.

Conversion kit technology is still in its relative infancy, so this could be a big area to take advantage of in the future.

Anyone aiming to build fitness may one day [9] reach the point when they no longer need any assistance, at which point they can convert their bike back to a standard mechanical model.

Are e-bike conversion kits worth it?

A conversion kit can be a significant investment so you shouldn't purchase one on a whim. Weigh up the pros and cons before buying one.

Among the considerations, think carefully about your bike. If it's an older model, there's a good chance you'll need to replace it soon.

When you add the cost of the conversion kit on top of a new mechanical bike, it will soon be reaching the level of a brand new e-bike, so why not just buy the latter?

You'll need the practical skills to fit the kit too. The alternative is a cost-incurring trip to the bike shop. Removing the kit can be an arduous task too.

If you plan to use it as a normal bike again in the future, it may be an extra hassle.

Then there is the simple question of how much you plan to ride the bike. There's no point in going through lots of effort if you only plan to ride very sporadically, or if it is going to be a short fad, before the converted bike is assigned to the garage where it is forgotten about.

If you're unsure, stick to a mechanical bike for now. You can always return to the idea in the future.

Are e-bike conversion kits legal?

Most countries now have laws that govern and set restrictions for e-bikes [11].

As long as your e-bike conversion kit adheres to these, it should be legal to use.

There are a couple of things to be wary of here. The first is the type of assistance. This will either be pedal assistance, whereby the rider needs to be pedalling, or throttle assist, when they don't. Some countries classify throttle assist bikes as mopeds [12], meaning they are subject to different laws and require a licence and registration for road use.

They're also not legal to use on bike paths or pavements. In other places, throttle assisted bikes are still classed as e-bikes.

Assistance limits are in place in many countries too. In the UK this is 15.5mph, while 25kph is popular among countries that use the metric system.

To be legal, an e-bike's motor must be capped so it can't provide assistance beyond these speeds, and the same rules apply to a conversion kit.

Remember, these laws are designed for your and other road users' safety [13], so you should always adhere to them.

How to convert your bike into an e-bike with a conversion kit

Unfortunately, there isn't an easy answer to this question as the process varies depending on the type of kit. Even kits that use the same type of system, for example mid-drive motors, will vary.

Follow the instructions provided by the conversion kit manufacturer carefully. If the kit is of high quality, the process should be manageable, but cheaper options may be more fiddly [14].

Double check the owner's handbook for the bike you're adding the kit to as well.

You don't want to do anything that could void the warranty on a bike or accidentally cause damage.

References

^ E-bikes (www.globalcyclingnetwork.com)
^ or want to find a greener alternative to driving (www.globalcyclingnetwork.com)
^ e-bikes hugely popular and the industry is in the midst of a boom (www.globalcyclingnetwork.com)
^ Rather than buying a new e-bike (www.globalcyclingnetwork.com)
^ Explore all of our e-bike buying advice and guides (www.globalcyclingnetwork.com)
^ Charging your electric bike: Everything you need to know about e-bike batteries (www.globalcyclingnetwork.com)
^ the e-bike market is a bewildering place to navigate (www.globalcyclingnetwork.com)
^ Every type of e-bike explained (www.globalcyclingnetwork.com)
^ Anyone aiming to build fitness may one day (www.globalcyclingnetwork.com)
^ 10 benefits of riding an e-bike (www.globalcyclingnetwork.com)
^ Most countries now have laws that govern and set restrictions for e-bikes (www.globalcyclingnetwork.com)
^ Some countries classify throttle assist bikes as mopeds (www.globalcyclingnetwork.com)
^ these laws are designed for your and other road users' safety (www.globalcyclingnetwork.com)
^ but cheaper options may be more fiddly (www.globalcyclingnetwork.com)