The suspension consisted of front drive sprockets, rear idlers and eight double-interleaved rubber-rimmed steel road wheels on each side, suspended on a dual torsion bar suspension. The dual torsion bar system, designed by Professor Ernst Lehr, allowed for a wide travel stroke and rapid oscillations with high reliability, thus allowing for relatively high speed travel by this heavy tank over undulating terrain. However, the extra space required for the bars running across the length of the bottom of the hull, below the turret basket, increased the overall height of the tank and also prevented an escape hatch in the hull bottom. When damaged by mines, the torsion bars often required a welding torch for removal.
The Panther's suspension was complicated to manufacture and the interleaved system made replacing inner road wheels time consuming. The interleaved wheels also had a tendency to become clogged with mud, rocks and ice, and could freeze solid overnight in the harsh winter weather of the Eastern Front. Shell damage could also cause the road wheels to jam together and become extremely difficult to separate. Interleaved wheels had long been standard on all German half-tracks. The extra wheels did provide better flotation and stability, and also provided more armor protection for the thin hull sides than smaller wheels or non-interleaved wheel systems, but the complexity meant that no other country ever adopted this design for their tanks. In September 1944, and again in March/April 1945, M.A.N. built a limited number of Panther tanks with steel roadwheels originally designed for the Tiger II and late series Tiger I tanks. Steel roadwheels were introduced from chassis number 121052 due to raw material constraints.
From November 1944 through February 1945, a conversion process began to use sleeve bearings in the Panther tank, as there was a shortage of ball bearings. The sleeve bearings were primarily used in the running gear; plans were made also to convert the transmission to sleeve bearings, but were not carried out as production of Panther tanks came to an end.
Steering and transmission:
Steering was accomplished through a seven-speed AK 7-200 synchromesh gearbox, designed by Zahnradfabrik Friedrichshafen, and a MAN single radius steering system, operated by steering levers. Each gear had a fixed radius of turning, ranging from five meters for 1st gear up to 80 meters for 7th gear. The driver was expected to judge the sharpness of a turn ahead of time and shift into the appropriate gear to turn the tank. The driver could also engage the brakes on one side to force a sharper turn. This manual steering was a much simplified design, compared to the more sophisticated dual-radius hydraulically controlled steering system of the Tiger tanks.
The AK 7-200 transmission was also capable of pivot turns, but this method of turning could accelerate failures of the final drive.
Throughout its career, the weakest parts were its final drive units. The problems were from a combination of factors. The original MAN proposal had called for the Panther to have an epicyclic gearing (hollow spur) system in the final drive, similar to that used in the Tiger I. However, Germany at the time suffered from a shortage of gear-cutting machine tools and, unlike the Tiger tanks, the Panther was intended to be produced in large numbers. To achieve the goal of higher production rates, numerous simplifications were made to the design and its manufacture. This process was aggressively pushed forward, sometimes against the wishes of designers and army officers, by the Chief Director of Armament and War Production, Karl-Otto Saur (who worked under, and later succeeded, Reichminister Speer). Consequently, the final drive was changed to a double spur system. Although much simpler to produce, the double spur gears had inherently higher internal impact and stress loads, making them prone to failure under the high torque requirements of the heavy Panther tank. Furthermore, high quality steel intended for double spur system was not available for mass production, and was replaced by 37MnSi5 tempered steel, which was unsuitable for high-stress gear. In contrast, both the Tiger II and the US M4 Sherman tank had double helical (herringbone gears) in their final drives, a system that reduced internal stress loads and was less complex than epicyclic gears.
Compounding these problems was the fact that the final drive's housing and gear mountings were too weak because of the type of steel used and/or the tight space allotted for the final drive. The final gear mountings deformed easily under the high torque and stress loads, pushing the gears out of alignment and resulting in failure. Due to the weakness of the final drives their average fatigue life was only 150 km. In Normandy, about half of the abandoned Panthers were found by the French to have broken final drives. However, at least the final gear housing was eventually replaced with stronger one, while final gear problem was never solved.
Plans were made to replace the final drive, either with a version of the original epicyclic gears planned by MAN, or with the final drive of the Tiger II. These plans were intertwined with the planning for the Panther II, which never came to fruition because Panzer Commission deemed that temporary drop in production of Panther due to merger of Tiger II and Panther II was unacceptable. It was estimated that building the epicyclic gear final drive would have required 2.2 times more machining work than double spur gears, and this would have affected manufacturing output.
Most of the shortcomings were considered acceptable once design flaws were rectified. Due to the mechanical unreliability of final gear Panther must be driven with care, a characteristic shared with the Tiger tanks as well as Jagdtigers. Long road marches would result in a significant number of losses due to breakdowns, and so the German Army had to ship the tanks by rail as close to the battlefield as possible.
Lieutenant Colonel Wilson M. Hawkins of the 2nd AD wrote the following comparing the US M4 Sherman and German Panther in a report to Allied headquarters:
"It has been claimed that our tank is the more maneuverable. In recent tests we put a captured German Mark V [Panther] against all models of our own. The German tank was the faster, both across country and on the highway and could make sharper turns. It was also the better hill climber"
This was backed up in an interview with Technical Sergeant Willard D. May of the 2nd AD who commented:
"I have taken instructions on the Mark V [Panther] and have found, first, it is easily as maneuverable as the Sherman; second the flotation exceeds that of the Sherman"
Staff Sergeant and Tank Platoon Sergeant Charles A Carden completes the comparison in his report:
"The Mark V [Panther] and IV [Tiger] in my opinion have more maneuverability and certainly more flotation. I have seen in many cases where the Mark V and VI tanks could maneuver nicely over ground where the M4 would bog down. On one occasion I saw at least 10 Royal Tigers [Tiger B] make a counter attack against us over ground that for us was nearly impassible"
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