August Momberger

During the season he took a further second-placed finish, and posted two fastest laps, but worsening arthritis and a deteriorating relationship with the Auto Union team manager forced him into retirement before the end of the year.

Following his retirement from racing, Momberger returned to his engineering training and rose steadily through the ranks of the German automobile industry, eventually becoming technical director of the Borgward company's Goliath division in Bremen.

In winning this race – a forerunner to the first German Grand Prix the following year – Momberger defeated works entries from many of the international motor industry including Mercedes and Bugatti.

For the 1927 Grand Prix season, Momberger switched his affiliation to Bugatti, and took this new car to the 5000 cc class victory at the inaugural Eifelrennen meeting celebrating the opening of the Nürburgring in June of that year.

Momberger joined the Daimler-Benz factory team for the 1929 Grand Prix season, driving the firm's new Mercedes-Benz SSK cars.

He won the third qualifying heat, but could only finish third in the race final, beaten by Achille Varzi's Alfa Romeo and Tazio Nuvolari in a Talbot.

New cars from their compatriots and rivals, Mercedes, had been withdrawn following pump troubles, so the main competition for the Auto Union team came from Scuderia Ferrari's streamlined Alfa Romeos.

By this point, Leiningen had already retired with a faulty radiator, so it was left to Momberger to challenge the Italian cars, and he set the fastest lap of the race at an average of over 140 mph (230 km/h) while chasing the lead.

However, from the start Momberger suffered from mechanical problems and rapidly dropped toward the rear of the 13 car field,[12] with only Tazio Nuvolari's misfiring Bugatti behind him, and he became the race's first retirement when his steering finally failed on lap 10.

The race was held on a chicane-peppered ad hoc adaptation of the Monza Autodrome – designed to improve safety at the notoriously dangerous track – and the winning Mercedes of Rudolf Caracciola took almost five hours to complete the scheduled 116 laps, at an average speed of only just over 65 mph (105 km/h).

[20] The condition had not improved by the end of the month and Walb decided to formally replace Momberger with Sebastian for the next race, Auto Union's final entry of the season, in Brno.