Full-suspension suspension makes pedelecs incomparably comfortable and improves traction and bike control. This requires high-quality components and intelligent rear suspension kinematics. In addition, a favourable ratio between sprung and unsprung mass is essential for good function. The unsprung mass essentially includes the wheels, brakes, rear swing arm and pannier rack. These components are positioned virtually in front of the suspension and should be as light as possible. They follow the road profile, while the sprung mass - consisting of the rider and the rest of the frame assembly - ideally remains on its horizontal plane with little movement.
As a general rule, the heavier the unsprung mass is compared to the sprung mass, the less sensitive a full suspension will be
Full-suspension riders feel this especially with a lot of luggage on the carrier. The additional load can lead to similar effects as with bikes without a rear swing arm, because the rear wheel is less able to follow the ground. It loses traction and, in the worst case, smears. Nevertheless, a full-suspension pedelec benefits even with a lot of weight on the carrier. This is because the high weight of the rider, motor, battery and the rest of the frame assembly is damped and the sprung masses remain high in relation to the unsprung masses. If the suspension and damping are correctly adjusted, the pedelec rolls safely over obstacles, even with luggage. Frame-mounted pannier racks turn the luggage into a suspended mass, but are rare exceptions.
In general, road shocks on full-suspension bikes only marginally penetrate the saddle. The rider sits more relaxed, can pedal more smoothly and does not tire as quickly. Traction is improved, the bike can be controlled more efficiently and rolls more safely. But full suspension doesn't just have advantages. The additional components make the bikes around 1 to 1.5 kilos heavier, and a full-suspension pedelec is a good 1,000 euros more expensive than an equivalently equipped bike without a rear swing arm. To maintain their function, the damping elements must be regularly maintained, adjusted and readjusted. And last but not least, the kinematics of the rear swing arm require a relatively large amount of space. Full suspension is often very difficult or impossible to integrate into small frames, ladies' frames and step-through bikes.
Pros and cons of full suspension:
+ very high comfort
+ improved traction
+ fatigue-free driving
- expensive
- maintenance-intensive
- not compatible with all frame shapes
Interview with Markus Greber
Photographer, EMTB test editor
MYBIKE: Do suspension rear triangles on crossover and touring pedelecs make sense at all?
Fullys are noticeably more comfortable to ride than bikes equipped only with suspension forks. And because the rear swingarm and fork not only compress but also dampen when rolling over obstacles, traction is significantly improved. Heavy pedelecs in particular benefit from this, as they roll more safely.
Does the full suspension cost energy when pedalling?
No, a correctly adjusted shock absorber system does not bounce inefficiently when pedalling. On the contrary: the system prevents bumps in the ground from reaching the rider via the wheels, frame and saddle. The rider sits more comfortably in the saddle and can pedal more evenly and smoothly. This is why a lockout function, which locks the fork and swingarm, makes little sense for crossover and touring pedelecs.
What are the disadvantages of full suspension?
The bikes are more expensive and require more maintenance than pedelecs without a rear swing arm. You cannot service the rear shock yourself. The additional components make the pedelecs somewhat heavier. However, this is hardly noticeable on motorised bikes. And on small frames or frames with a low step-through, there is simply not enough space for full suspension.
