MY22H03 - 22_1.0_01.10.2021
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Overview
3.3.3.3 Rear frame damper
A rear frame damper is primarily fitted to mountain
bikes and helps to protect the pedelec and rider
against impacts and vibrations caused by uneven
ground. A rear frame damper deflects when a
steel spring, air suspension, or both suspension
types act on it.
Negative deflection (sag)
The sag is the percentage of total spring
deflection that is compressed by the rider’s body
weight, including equipment (such as a
backpack), their seating position and frame
geometry. Sag is not caused by riding.
The rear frame damper rebounds at a controlled
speed if it is optimally adjusted. The rear wheel
does not bounce off rough surfaces or the ground;
it stays in contact with the ground instead
(blue line).
The saddle is raised slightly if the bump is
compensated and gently sinks downwards when
the suspension deflects as soon as the wheel
touches the ground after the bump. The rear
frame damper rebounds in a controlled way, so
that the rider remains sitting in a horizontal
position when the next bump is absorbed. The
suspension motion is predictable and controlled.
The rider is not thrown upwards or forwards
(green line).
Figure 15: Optimum rear frame damper ride performance
When optimally adjusted, the rear frame damper
counteracts deflection, stays higher in its
deflection range and helps to maintain speed
when riding on hilly parts of terrain.
Figure 16: Optimum rear frame damper ride performance on hilly terrain
