6C 1927 to 1933
Alfa Romeo 6C 1927 to 1933
Along with the P2 and later 8C models, this range of cars developed from the 6C 1500 of 1927 are the core of Alfa's competition identity. Desperate for new road cars to replace the RL and RM, whose sales had tailed off dramatically, Jano built a smaller 6 cylinder version of his P2 GP engine, removed the supercharger and put it in a usefully light body and chassis. It was a risky venture, as the capacity was much smaller than the accepted norm for a full-sized sportscar.
The six-cylinder cars built an impressive sportscar (and even GP!) record at every significant racing venue before the war, and were developed relentlessly, making them excellent road cars also. Even the Second World War interrupted this only a little; as the 2500 model was released in 1938, was built well into the war years, then continued on into the early 1950s. All the models were quick and attractive, some are iconic! This guide is to the original models developed from the 1500.
The earliest of these cars are nearly a century old, so it would be no surprise to find them on non-standard wheels and tyres. As a result, this is a guide only to standard fitments when new. Even then, not all the cars would have had standard tyres, and records can sometimes be contradictory. Please contact us if you would like to discuss fitments.
6C 1500 - In 1927, the standard tyre for the Normale models was a 29x5 crossply tyre (equivalent to a 500-19). In 1928 this changed to a 30x5.25 (equivalent to a 525-20). In 1929 the standard was a 28x4.95 (again equivalent to a 500-19). The sportier models (Sport and Super Sport) were fitted with a 27x4.75 tyre (equivalent to a 475-18).
6C 1750 - This model was built in more versions and by a greater variety of coachbuilders, so there is more variation in tyre fitment. As a general guide, cars supplied to the UK (in all versions) in 1929-31 had 27x4.75 (equivalent to 475-18) tyres. In 1932 things were a little less standard, some cars had 18-inch wheels, fitted with either 525-18, or 550-18; and some had 19-inch wheels with 450-19 or 525-19 tyres. From 1932 to the end of production it's a bit simpler - the majority of cars were fitted with 28x5.25 (525-18) tyres.
6C 1900 - The last development of the 1500 model. Available as a Gran Sport only, and only made in 1933. Its standard tyre was a 28x5.25 (525-18)