There were several tyre options fitted to different Allegro models, they were:
Allegro 1 (1973 to 1975) Saloon 1100, 1300, 1500 - Fitted with a 145SR13 radial tyre as standard
Allegro 1 (1973 to 1975) Saloon 1750 - Fitted with a 155SR13 radial tyre as standard
Allegro 2 (1975 to 1979) Saloon 1100, 1300, 1500 - Fitted with a 145SR13 radial tyre as standard
Allegro 2 (1975 to 1979) Estate 1300, 1500 - Fitted with a 145SR13 radial tyre as standard until 1978 when a 155SR13 was fitted
Allegro 2 (1975 to 1979) Saloon and Estate 1750 - Fitted with a 155SR13 radial tyre as standard
Allegro 3 (1979 to 1982) Saloon 1100, 1300 - Fitted with a 145SR13 radial tyre as standard
Allegro 3 (1979 to 1982) Saloon 1500 - Fitted with a 155SR13 radial tyre as standard
Allegro 3 (1979 to 1982) Estate 1300 - Fitted with a 145SR13 radial tyre as standard
Allegro 3 (1979 to 1982) Saloon and Estate 1500, 17500 - Fitted with a 155SR13 radial tyre as standard
Allegro Equipe (1979 to 1982) - Fitted with a 165/70SR13 radial tyre as standard
The Allegro was the small family replacement for the successful 1100 and 1300 models. It wasn't the sales success of its predecessors, and became part of the slow decline of BL in the 70s, as its products started to look uncompetitive.