Rusting on the metal parts such as the undercarriage, the hinge and the tires of the kamado is almost unavoidable if it is left outside all year round. This has to do with humidity. Even if the kamado is dry, for example under a veranda, and the cover is used, condensation will still form on the sheet metal due to temperature differences.
You can maintain this, so that rust has as little influence as possible on the kamado. It is important that it is regularly rubbed with, for example, WD40 so that the sheet metal remains well greased and moisture can get the least amount of grip on it. To reduce rust formation, you can carefully rub the rust spots with a very fine sandpaper or scouring pad and then apply the tip with WD40.
Spray the metal parts such as the undercarriage, tires and the hinge with WD40, so that they are more resistant to weather conditions such as rain and frost.