Production restarted in December 1943 of another 60 vehicles, using only new Ausf. H chassis, and continued until March 1944. The Sturmpanzer's baptism in combat at the Battle of Kursk proved that the driver's compartment was too lightly armored and it was reinforced. The gunner's hatch was removed and a ventilator fan was fitted, much to the relief of the crew. Internally sprung, steel-rimmed road wheels replaced the front two rubber-rimmed road wheels in an effort to reduce the stress on the forward suspension that was only partially successful.