Absolutely none. Nor is it required to lubricate any parts in the drive unit nor disassemble it... all you have to do is taking care for it as a traditional mountain bike. It is important to mention, however, as a precaution applicable to any mountain bike: electronic parts and, specifically, the bottom bracket area of the drive unit should never be cleaned with any high-pressure washer machine. Therefore, it is not possible to use high-pressure water to clean the cranks axle directly as the electronic parts of the drive unit can be seriously damaged.