The first Speed 20, the SA was fitted with a 525-20 crossply tyre.
The SB (and the following SC), introduced for 1934, had a 525-19 crossply on a new 19-inch wheel.
The final SD version of 1936 got a slightly wider 550-19 crossply tyre, as did the bigger-engined 3.5 Litre (SA).
The Speed 20 was a successful touring car for Alvis. It's sporting looks and good performance were backed up with fine suspension and handling. Available as saloons, coupes, tourers and cabriolets. Progressively improved, its run-out model had a bigger 3.5 Litre engine for bigger more luxurious bodies, and went on after the end of the standard model as the Speed 25 SB short-wheelbase model.