What is the maximum diameter that the CIO bike lights can be mounted on? Mille Stech Jensen November 08, 2017 14:41 Updated Front light: Ø50m / 1.96 inch Rear light: Ø35mm / 1.38 inch Related articles Does the light fit all kinds of bikes? Are the lights waterproof? On which side of the bike should CIO be mounted? How much does the CIO bike light weigh? CIO Comments 0 comments Article is closed for comments.