Disc Brakes

From GTM Workshop

Calculating your disc size

Measuring your disc size can be difficult without totally removing them, however it is possible to measure across one part of your disc (called a wp:chord) and measure from the chord to the disc edge (height) to calculate the disc diameter. This website has a handy calculator to do the hard work for you: http://www.1728.com/circsect.htm (in the diagram "circle 2" the chord is A-B and the height is E-D)