Print 1 per tyre. Drive the car onto the tyre-up.

Make sure the tyre is hanging over the edge with the sidewall. You can clean/dress the tyre without the bottom touching the ground leaving an untreated spot.

As an extra there's also a pressure washer hose guide on the front of the item so the hose won't get stuck under the tyre while cleaning around the car.

Print instructions:

Use a strong filament like PETG at 50% infill, gyroid. This should be strong enough.

You can reduce infill when you plan to use it with a lighter car.