developing the 250 Bialbero in 1955, NSU (fifth with Horst Kassner) had withdrawn its factory team at the end of 1955 after the deaths of Rupert Hollaus and Gustav Baumm, and Kassner rode with an NSU Sportmax production racer. ČZ machines were by no means at the level of the Western brands, František Bartoš was only twelfth. In 1957 the fortunes for MV Agusta changed. First, Mondial appeared with the 250 Bialbero and two top drivers: Cecil Sandford, who was the 1952 125 cc Champion, and brought experience to the team, and Tarquinio Provini, who was only 23 years old but very talented. The season started well for MV Agusta: Carlo Ubbiali won the first Grand Prix at the Hockenheimring and his teammate Roberto Colombo came in second. In the Lightweight TT, Taveri and Colombo came in second and third behind Sandford, while Provini set the fastest lap. Ubbiali and Provini dropped out. In Assen the MVs did not start. Provini won convincingly, ahead of Sandford and Sammy Miller. Remarkably, MV Agusta dropped this race, Colombo was there, but only started in the 125cc class, in which he finished second. Roberto Colombo died following an accident during practice for Spa-Francorchamps when he was using the MV Agusta 350 4C. MV withdrew from the 250 cc class for the rest of the season. However, John Hartle, on an experimental twin-cylinder MV Agusta still raced in Spa and won. Roberto Colombo was posthumously the best 250 cc MV driver that season. He finished fourth in the Championship, Ubbiali came fifth. The fall of 1957 proved be a turning point for world road racing championships. All major Italian brands (Mondial, Moto Guzzi, Gilera and MV Agusta) decided to withdraw en bloc from the World Championships. The costs of racing were huge and disproportionate to the sales. For Moto Guzzi and Gilera this was especially so, because their income was solely from motorcycle sales. Mondial was able to make some money with transport tricycles and for Agusta, motorcycle production was still more a hobby than a profession. Count Domenico Agusta reversed his decision and continued the racing activities. In 1958, MV Agusta was the only remaining top racing marque competing, so could engage the top drivers of the time: John Surtees and John Hartle in the 350 and 500 cc classes and Tarquinio Provini and Carlo Ubbiali in the 125 cc and 250 cc