Choosing an electric bike with or without derailleur?

Among all the criteria for choosing an electric bicycle, the presence or absence of a derailleur is particularly important. Indeed, the derailleur is an element of transmission and gear change system that in the case of an electric bike can also determine the location of the motor.

We therefore propose a guide to discover the differences between electric bikes with a classic derailleur and models with a transmission mode by hub with integrated gears. These differences impact the comfort of use, the pedaling sensation, the price and the maintenance of the EAB (electrically assisted bicycle).

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Electric bikes with derailleur transmission

The external derailleur transmission system is the one that every cyclist has already seen and used, whether we are talking about a city bike, a mountain bike, a classic bike or an electrically assisted model.

The derailleur, attached to the frame of the bicycle at the rear wheel, allows the chain to move from one sprocket to another and thus change the speed by modifying the development, i.e. the distance covered with each turn of the pedal and wheel. Derailleurs are available in mechanical (cable) and electronic versions, in which case a motor triggers the movements of the derailleur.

The advantages of the traditional derailleur

The traditional derailleur is a system that has the first advantage of being very simple in design, which translates into a low manufacturing and sales price. The same is true for the cost of maintenance or replacement, which remains very reasonable and accessible.

Moreover, compared to a transmission with integrated gears, the derailleur is light, so that it has very little impact on the total weight of the bike.

Furthermore, derailleurs with sprockets associated with a chainring located at the bottom bracket, offer a large number of ratios and gears, allowing the cyclist to find a gear adapted to all types of terrain (road, track, mountain, etc.). This is why bikes with derailleurs are preferred for sport cycling.

The derailleur is the most common transmission and gearing system used on EABs and offers a wider range of models and brands: city bikes, mountain bikes, men's, women's or children's models.

The disadvantages of the derailleur

The position of the derailleur, next to the rear wheel, is responsible for its main drawback: being exposed to shocks, dust or rain. This exposure causes the derailleur to clog and age more quickly, requiring maintenance, adjustment or replacement.

The bike chain is also under much more stress, which means it must be replaced when it jumps off the sprockets or chainring, and it must be maintained or changed regularly. Any cyclist who has experienced having to put a chain back on when it gets stuck between the derailleur and the rear wheel can testify to the difficulty of the task and how dirty his or her fingers are when in contact with grease and sludge.

Regarding the practice of cycling and the feeling of pedaling, traditional derailleurs are known for their poor adaptation to a comfortable use in town and urban environment. Indeed, with an electric bike with derailleur, it is impossible to change gear when stopped. Therefore, when a cyclist at a good speed has to stop at a red light, he has to use all his pedaling power to start again, before he can change gear.

This problem can be solved with the electronically controlled derailleur solution, but the bike loses two advantages: its price and weight become higher. In addition, electronic motor shifting draws power from the EAB battery, reducingbattery life.

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Hub transmission systems

The alternative to derailleurs is called a hub and spoke transmission. This means that gear changes are made through a gear mechanism located in the hub of the rear wheel of the electric bicycle.

With such a system, only one sprocket is visible on the rear wheel axle and the derailleur is then designated as internal. A hub drive system can offer anywhere from 3 to 14 gears, depending on the model.

What are the disadvantages of hubs with integrated gears?

Hub-integrated transmission and shifting are more expensive and heavier technologies than external derailleurs, which impacts the price and weight of the EABs equipped with them.

It is also necessary to take into account a specificity of the transmission by hub, which is a great sensitivity to the pedaling power and which imposes to stop pedaling about one second during the changes of speed. This practical aspect is the one that makes sport cyclists (road, trail and mountain) generally prefer the traditional derailleur operating mode, more reactive and controllable.

The advantages of hub transmission

Electric bikes with a gear shifting system integrated into the rear wheel hub have a practical and mechanical advantage: reliability.

The entire system is protected from the elements, which means it will last for thousands of miles without a hitch. In addition, since the bicycle chain no longer needs to move from one sprocket to another during gear changes, there is no risk of it derailing.

Furthermore, if hub transmission electric bikes are recommended for better comfort in the city, it is because they offer the possibility of always being in the right gear, having only to concentrate on the steering and the crankset. In contrast to external cranksets, hub systems allow you to stop at a red light or stop sign and automatically shift into the right gear. This avoids unnecessary and sometimes dangerous efforts by the cyclist. Forcing the pedals when starting can cause a pitching or falling phenomenon for novices.

Being able to change gears at a standstill is a feature that gives electric bikes an undeniable improvement in comfort of use in the city, compared to bikes with external derailleurs.

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