Measuring along this imaginary line can sometimes be tricky. Luckily, it's possible to calculate the BCD of a chainring by simply measuring the center-to-center distance of two adjacent bolt holes. With this measurement ("B") you can refer to the table below to identify the corresponding BCD, or use one of the following equations: Jun 10, 2009 · Bicycle frame sizes and tire sizes differ, but neither of these apply when talking about whether a bicycle is 16 inches, 24 inches, 26 inches, 27 inches or 700 millimetres. These designations can be confusing, but one wonders how a manufacturer determines what to call a push bike's rim size. Diamondback - MTN 100 % Suspensions , pile Hardtail , Devine Models , Comfort ,Cruiser , Efficiency a mix of both , a mix of both , Youth , BMX Fuji - road, pile, Specialized, Ladies, Way of living, Little ones