Gear ratio calculator for Bromptons and other hub- (and fixed-) geared bicycles.

Untick the 'Brompton-compatible data only' box to reveal extra hub and tyre options. ('Brompton-compatible' includes tyres and hubs known to have been fitted to the Brompton. Not an exhaustive list.)

If you have any questions, comments or corrections, please feel free to contact the developer.

To link to the calculator please use this URL: http://xldev.co.uk/bgc.html