In the prospect of obtaining very high speeds on the straight sections of the Hockenheim track Ferrari schemed up some streamlined spats which fitted behind the rear wheels of the 312T2 cars, but neither Lauda, in 031, nor Reutemann in 029, could detect any difference, so the idea was discarded. This season the Ferrari team have been keeping to the same cars, rather than running a rota system as in the past, and they had with them 027 as the spare, though it was not used.
Team Lotus having offered the original Type 78 for sale to a suitable driver, took numbers 2, 3 and 4 to the German GP and though Andretti and Nilsson practised with 3 and 2, respectively, the Swedish driver took the later car, 78/4 for the race, as his own car had trouble with the engine mountings. Similarly, Watson changed to the spare Brabham, as he had done at the British GP, because it felt better than the car he should have used. He started practice with BT45/6B, the latest car to be built, but soon changed to BT45/1B and retained it for the race.
The spare Shadow, DN8/4A was fitted with smoother outline body panels, but was only used by Jones during the untimed practice on Saturday morning; he and Patrese driving their usual cars. Scheckter had Wolves numbers 2 and 3, using WR2 for practice and the race, but doing some comparative tests with WR3 during the untimed practice session. In the Hesketh team Keegan used the latest car, 308E/4, while Rebaque used 308E/2, normally driven by Ertl.
The Ligier team had a brand new car with then, number IS7/03 and this was kept as a spare to back up the usual car driven by Laffite, number JS7/02, while Fittipaldi had the second of his 05-series cars, which had first appeared at the British GP.