The soul of an electric bicycle is the motor itself, so the most important priority when it comes to buying an electric bicycle is to decide what type of motor we want to power our future bike. Indeed, there are a large variety of motor types on the market, so choosing one isn’t the easiest thing to do.
The three main categories are the following: Front wheel drive eBikes, mid-drive, or crank driven electric bikes, and rear hub motor powered eBikes, or just hub motor driven eBikes. As a rule, most hub motor powered eBikes are rear wheel drive only.
You can find front hub motor powered eBikes as well, although those are usually DIY or custom-made electric bicycles. Interestingly, there are also all-wheel drive electric bicycles that represent a very a small sub-niche within the industry, which we are going to discuss in the future in a separate article. In this article, we are going to dive deep into the crank driven and hub motor powered eBike (RWD) world.
Front wheel drive eBikes and kits: In case you would prefer to have a front wheel driven eBike built by yourself, then this is the category that will cost you the least amount of time, energy, and money. As a result, there’s no need to do complex modifications, and kits can be installed to most classic non-electric bicycles as well.
Traction is something you’ll have to keep in mind because it’s not always going to be as expected, especially in wet conditions and steep uphill terrain. Since your bodyweight is mainly supported over the rear wheel, the front wheel will have a hard time maintaining traction. Front wheel spinning is a frequently experienced effect on front hub motor powered bikes. In any event, this can make staying on your eBike tricky.
Rear hub motor powered bikes
Better weight distribution, more pleasant riding experience – simple as that. If you jump over from an FWD eBike to a rear hub motor powered bike, you can experience the positive effects of the rear hub motor right away. As mentioned above, your weight is supported mainly by the rear wheel, so you get better traction on uphill and wet conditions.
Installing a rear hub motor may be slightly more difficult when compared to a front wheel kit, yet it is still relatively easy to do so. A hub motor is a lightweight and compact system, so you won’t need to sacrifice the overall aesthetics of your bicycle. Due to the simplicity of the motor, rear hub motor systems are the most popular among bike manufacturing companies. Therefore, rear hub motor driven eBikes fill up most of the eBike stores. There are two types of hub motors: – Geared hub motors or planetary gear reduction systems – Gearless hub motors or direct drive motors or brushless motors.
Geared Hub motors are usually smaller in size, as there is no direct connection to the shaft. With a small size, comes a smaller weight as well. This system is able to turn the motor at higher revs when compared to gearless hub motor systems. Faster-turning motors are more efficient climbers on steep ascents: but are also noisier.
Considering there are multiple components in the motor case, parts can certainly wear out quickly. Geared hub motors are usually equipped with small plastic gears inside. Changing them to metal gears can increase the lifespan of the motor, although it will result in an even greater noise as well. All the same, if weight is more important for you than performance, geared hub motors are the recommended solution to go for.
The Gearless Hub motor or direct drive motor is driving the axle directly, as its name suggests. Therefore, it is a much more simple system compared to geared hub motors. It is heavier and larger in size. Due to it’s larger size, with the right controller, it can have regenerating capabilities as well. The motor runs without vibration and noise. As a result, you won’t be able to notice whether it’s on or off. Conversely, if performance is a more important factor than weight, gearless hub motors are the choice to go for.
Crank drive motors or mid drive motors are the happy medium between front and rear hub motors. They come with the all the positive factors that hub motors have but with better efficiency. Crank drive motors are positioned near to the bottom bracket and drive the crank directly, which then delivers the power to the rear wheel via the chainring and chain.
Above all, this allows nearly perfect weight distribution and a low center of gravity which then results in overall improved handling. Removing the wheels doesn’t require any compromise with this system, therefore it can be used on front dynamo equipped bikes and internal gear hub equipped bikes as well. Not only can the wheels be removed and replaced easily, but this is also true for the motor itself that it’s designed to make service and maintenance cost effective, but obviously in case of a serious failure in the motor, it can get very expensive as well.
Building a crank driven bike requires frame modifications in order to install the motor correctly, so doing it yourself can be a real challenge. For the most part, attacking this with high precision and focus can make the project a worthwhile time investment, although it may not be as cheap as buying a new factory-built crank driven bike.
Of course, crank drive motors are not perfect either. For example, they are unable to regenerate energy by their very nature. The chain, sprockets, and cogs are the ones that providing the hard work hence they tend to wear out more often on crank driven eBikes.