Move the two pickups on the rocker. Black drives from the pushrod, oxblood drives the damper. The linkage re-solves through the whole travel and every plate below follows. Hover any plate to place the wheel there.
On the rocker, motion ratio is simply hd ÷ hp: the perpendicular distance from the pivot to the damper's line of action over the same distance to the pushrod's. Each is arm length × sin(angle to its link). Everything in this chapter is that one sentence, seen four ways.
Left rail: wheel travel in 10 mm steps. Right rail: the damper at each of those steps, drawn at static-ratio scale, so a linear set-up gives parallel rungs. Rungs that spread toward bump are rising rate. Bars give damper millimetres per 10 mm of wheel.
Each effective arm is arm length × sin(angle between arm and link), at its peak at 90°. The heavy band is the stretch of curve each arm sweeps through travel; the arrowhead points to bump. A pushrod band leaving 90° and a damper band arriving at 90° both add rising rate.
The dashed perpendiculars on the mechanism, measured through travel. Rocker ratio is hd ÷ hp. Rising rate is hp shrinking or hd growing in bump.
Motion ratio = pushrod stroke per millimetre of wheel × rocker ratio. The first factor is fixed by where the pushrod meets the wishbone and barely moves. The progression lives almost entirely in the rocker.
Wheel rate scales with the square of motion ratio, so a 20% rise in ratio is a 44% rise in rate. Every plate shares one travel axis: droop on the left, bump on the right.
The slope is the progression. Flat is linear, rising to the right is rising rate, falling is falling rate. A gap means the rocker reaches dead centre and the linkage locks.
The raw kinematic output; ratio is its slope. Rising rate makes the curve convex: it bows above the static tangent at both ends.
The solid line carries the geometric term, spring force × dMR/dz. With a preloaded spring a changing ratio adds rate on top of k·MR², and the gap grows with corner load.
Change in vertical tyre load from static. Rising rate bends the curve away from the straight reference: the last 20 mm of bump costs far more load than the first.
Every cell is a complete re-solve with the pushrod and damper pickups rotated to that pair of angles, at the current arm lengths. Tone is the progression: ratio at full bump ÷ ratio at full droop. Click to move the pickups there.
The pale band is linear. Along it one arm's lever shrinks exactly as fast as the other's.
Oxblood is rising. The pushrod arm passes 90° to its rod early, the damper arm reaches 90° to its damper late. Both levers move the same way and the effect compounds.
Tight contours mean sensitivity. One degree of pickup position changes the progression a lot, so tolerance and rocker flex matter more there.
Hatched cells lock. An arm lines up with its link before full travel. Approaching that edge the ratio runs away, the extreme form of rising or falling rate.
Length sets scale, angle sets shape. Damper arm length scales the ratio almost uniformly; rotating a pickup changes the slope.
Model: planar front-view linkage. The lower wishbone pivots inboard at a fixed point; wheel travel is measured at the contact patch, 510 mm outboard of it. The pushrod mounts on the wishbone 395 mm out and drives a rocker on a fixed chassis pivot; the damper runs from the rocker to a fixed chassis mount. Motion ratio is solved from exact circle-intersection kinematics at 0.25 mm steps. Camber change and compliance are ignored. True wheel rate is d(wheel load)/dz with the spring preloaded to carry the static corner load. Wheel damping scales with MR² exactly as spring rate does.