The Antares roller means that you can cycle freely to refine your coordination & technique. Its a favourite among track riders for warming up. This roller can be retracted to 80 cm. The rollers themselves are conical to ensure your bike always stays in the middle of the roller you are riding on. A training/ warmup favourite of the proffesionals, you can take this marvellous kit anywhere. FEATURES Type of trainer: Roller Roller diameter: 100-110mm (3.93-4.33") Suitable bikes: All bikes with a wheel diameter of 26 to 29"