The large diameter (and very heavy) hub reduces the amount of space between the hub and the rim and as a result many wheels are built ‘2 cross’ (i.e. each spoke crosses another spoke twice) and stress is also put on the spoke by the accentuated angle that the spoke runs at as soon as it leaves the nipple due to that reduced amount of space – this is where most spoke breakages occur. With the right rim it’s possible to get a ‘3 cross’ build which doesn’t accentuate the angle and is therefore much stronger. This is import as not only does the wheel have to cope with the heavier weight of the bike (before you add in the rider) is also has to cope with the drive of the motor and opposing force of braking so it’s quite common for electric bike to suffer from repeatedly broken spokes.

These bikes are increasingly popular, however, many of the wheels are cheaply built as other components cost so much.