Never wondered why the lug nuts are to be tightened in a crosswise order?
This is done to avoid even a minimum misalignment between the contact surface of the wheel and the wheel hub. If we tighten the lug nuts in any other way, the wheel can end up with a 0.3–0.5 mm misalignment, and, however tiny it may seem, this will be enough to make the wheel wobble, which will lead to the passengers’ discomfort, and damage the suspension.
It is because of this that neither the wheel hub nor the contact area of the wheel is ever painted. Even at the factory. Because the layer of paint even a fraction of a millimeter thick can cause a wobbling effect and using such wheel will become a nightmare. Many car tuning enthusiasts are unaware of that, and, looking to adorn their vehicle, cover the calipers and the hubs with paint.
At the same time, it is important to know the difference between painting the caliper and painting the hub. There are special enamels for painting the caliper and this practice is widespread. But the wheel hub itself must not be painted.
The same applies to repairing and painting the wheel discs. The contact area is not to be painted under any circumstances.
By the way, for this same reason the competent car repair services always clean and oil the wheel hub when replacing the wheels.
