L.R. / Leverage Ratio: relationship between rear-wheel travel and shock compression. The ratio constantly changes throughout the wheel’s travel range. We focused and worked on the following aspects for our Kern range:
Shape of the LR curve :
Progressive : to maintain stability throughout the travel range and to avoid bottoming out. Parabolic: to quickly lower the ratio around SAG and thereby get better support from the suspension. The relationship between suspension and SAG is important in order to avoid stability problems.
0 to 60 mm : High ratios (between 2.9 and 2.6) provide comfortable and relatively soft suspension. The progressive shape makes it easy to reach the SAG value (a ratio of around 2.65) and facilitates negative travel, which is important for the bike to move smoothly over broken ground.
60 to 120 mm : (ratios between 2.6 and 2.4) the curve is still progressive, but ratio reduction is slowed; suspension is firmer and gives better grip.
120 to 160mm : (ratios between 2.4 and 2.38) the curve bottoms out at 150 mm travel (2.37). The progressive shift in ratios from 2.9 to 2.37 stops the shock bottoming out at the end of travel. At the very end of travel, the force exerted on a pneumatic spring (air shock) increases quicker than the travel (Ramping), which means maximum travel is never reached. This is why, to compensate for the ultra stiffness of the air shock, we’ve slightly lifted the curve again at the end of travel (from 2.37 to 2.40).