In my personal opinion, there are two reasons
1. Moment of inertia, which affects power consumption and wheel response and transmission load.
2. The center of mass of the wheel is in the center of the axle no matter how much weight is added to the wheel, the center of mass of the weight at the end of the axle can be under the axle, which is a higher gain for the same weight, of course, if your whole car’s center of gravity is very upward, the wheel will still gain a lot by adding weight to the wheel.
In addition, there is an optimal weight for wheel grip, which needs to be tested according to the actual situation.
