Types of gearing
There are two types of gearing: derailleur gearing and internally geared hubs. When you want to install a mid drive kit, the kit will work with both types. Easy as. The only thing with mid drive kits is that you will lose your front derailleur (if you have one), because the motor only allows one front chainring to be installed. So with mid drive kits you will only be able to keep the gears in the rear.
With hub drive conversion kits it can be slightly more complicated. If you’re doing a front wheel conversion, no worries. You’re not interfering with the gearing and therefore you don’t need to take this part into consideration.
If you’re doing a rear wheel conversion you need to pay attention: you can’t do a rear wheel conversion if you have an internally geared hub in the rear. That entire wheel will be replaced with the motor wheel, and the motor will take up the space where the internally geared hub was. So if you have an internally geared hub and you want to do a rear wheel conversion, you’d have to either use the kit with a single speed (not particularly recommended, explained below) or change to a derailleur system. Also note that you can only use the threaded, screw-on type freewheels in combination with the rear hub motors, you can’t use splined cassettes.
Why are gears useful on an electric bike?
When you add a motor to a normal bike, you don’t really feel the need for the gears as the motor makes pedalling so much easier. But gears are still useful on an electric bike, because they will help the motor to perform better and help save on battery life.
When using the proper gearing, the motor, controller, and battery won’t have to work as hard and will perform better for a longer time. For instance, when you go up a hill in a high gear instead of a low gear, the motor will have to work so much harder to get you up that hill. This also means that the motor will put more strain on the battery and controller, which will cause these components to age more quickly. So, if you want to use your electric bike for a long time, it helps to help the motor by choosing the right gear for the job!