Imperial Tyres

A 27-inch imperial bicycle tyre is a classic size once standard on road bikes before metric 700C tyres became dominant. Measuring roughly 630 mm in bead seat diameter, it fits older touring and racing bicycles, offering smooth rolling on paved surfaces. Tyres in this size are typically narrow (1¼"–1⅜") and designed for high pressure to reduce rolling resistance. Modern replacements remain available from brands like Schwalbe and Continental, ensuring continued use of vintage bikes. Though largely replaced by the 700C (622 mm) standard, 27-inch tyres remain valued by enthusiasts restoring older frames for their authentic fit and ride quality.