In April 1941, production of the Panzer IV Ausf. F started. It featured 50 mm (1.97 in) single-plate armor on the turret and hull, as opposed to the appliqué armor added to the Ausf. E, and a further increase in side armor to 30 mm (1.18 in). The weight of the vehicle was now 22.3 tonnes (24.6 short tons), which required a corresponding modification of track width from 380 to 400 mm (14.96 to 15.75 in) to reduce ground pressure. The wider tracks also facilitated the fitting of ice sprags, and the rear idler wheel and front sprocket were modified. The designation Ausf. F was changed in the meantime to Ausf. F1, after the distinct new model, the Ausf. F2, appeared. A total of 471 Ausf. F (later temporary called F1) tanks were produced from April 1941 to March 1942.