Hello, you know, during the trip on holiday I drove the BAB behind Heilbronn in the direction of Würzburg, but also other bad motorway sections (e.g. at Soltau) The lanes are so old and in a miserable condition, that I ate every time with the rear axle on the buffer with the unevenness. First I did not understand these blows and went to the rear during the trip with approx. 90 km/h. With every plate change (probably still from Hitler’s times) there was At home I measured the distances between the buffer and the frame. At a rear axle load of 1.86 t, the distance hi left 11 mm and back right 9 mm (The water tank is left !) What distance must still be available at maximum load? Is there a way to increase the travel of the spring? What is the cost of air suspension? Is this advantageous for the driving characteristics o What does the tyre pressure have to be? Thanks for the information PS: Fiat Ducato, 3,5 t, Bj 2017