The CIO bike light fits all the bikes we have been testing so far. From our point of view the mounting and function of the CIO bike light can be problematic on a bike with 16 inch wheels or smaller, or on bikes with low angled seat stays. Therefore, we do not recommend to mount CIO on those bike types.
If you have a front fork with a large diameter, remember that you can extend the wire by rotating the key counter-clockwise.
If the bike light does not fit your bike upon arrival please contact our support team.