The Porsche tractor design included a hydraulic coupling between engine and transmission; this distinctive feature of Porsche-Diesel engines was used in tractors until the last model produced in 1963. Engineers in the 1930’s believed that farmers in those days were not able to handle a clutch properly when shifting gears. Prof. Dr. F. Porsche produced three prototype tractors in 1934, all equipped with petrol engines. The Porsche diesel engine with its unique air-cooled feature was not quite ready for production.
After WWII only companies in Germany who were producing farm tractors during and prior to the war were allowed to continue producing those tractors. Since Porsche was not one of these companies it signed licensing agreements with the German company Allgaier GmbH and the Austrian company Hofherr Schrantz. These two companies used the Porsche engine design and called their tractor: Allgaier System Porsche and Hofherr Schrantz System Porsche.
In 1956 Porsche took over the production of the AP 22 from Allgaier and produced the AP 22 until 1957. The tractor on offer is the rarer narrow – track version used mainly by viticulture farmers. Said to be in good overall condition by the vendor. These sought after models are ever increasing in value and desirability in the historic tractor market.