This race was run under Formula Libre regulations, namely, no weight or power limit for the engine.

[2] In order to obtain the best possible results and take advantage of the long straights, Mercedes rebodied three of its cars according to the "Streamline" style.

The first, entered in the race under number 35 and entrusted to Rudolf Caracciola was a W125 equipped with its original M125 engine.

The second, entered in the race under number 36 and entrusted to Manfred von Brauchitsch was a W25K in which a 736 hp DAB engine had been installed.

The last, entered in the race under number 37 and entrusted to Hermann Lang was a W25 equipped with an M125 engine.