Fatbax was a series, which debuted 2004 in the First Editions series. All 10 cars had giant rear wheels and tiny front wheels. The cars itself were wedge-shaped and often had exaggerated engine sizes. Because of their large rear wheels, they could not fit on hotwheels track, and could only work on very few playsets. The cars with this odd design caused a financial loss for Mattel and the sales of Fatbax cars were unsuccessful. They were found in stores in 2005. Fatbax cars will never be produced again. The rear wheels have all the same size on every Fatbax model.