During the production of the Model AA, the wheels were also changed. Spoked wheels similar in appearance to Model A wheels but much heavier were used during 1928. Twenty inch 6 slot disc wheels were produced by Budd for Ford during 1929. In 1930, a new style 20 inch 5 slot disc wheel was adopted. These wheels were used for 1930 and part of 1931. The final wheels were a further modification of the 1930 wheel, with a raised center to reinforce the wheels and allow spacing of dual wheels in the rear so the tires would not rub against each other. The dual wheels were used for a variety of body styles, including dump trucks, tow trucks, tankers, fire trucks, and flatbed stake trucks. Wheel nuts changed with each new style of wheel to meet the changes made in the designs of the wheel. Special wheels were produced for ambulances, buses, and funeral coaches (hearses).