Harshness Conditions

Harshness is the term commonly used to describe the ride quality of the vehicle. Hard ride or harshness is usually caused by the tires or suspension system, namely:

- Over-inflated tire installed on the vehicle.
- Worn suspension components.
- Suspension components installed with preload on pivot points, bearings and bushings.
- Units equipped with tires not specified by the manufacturer. (Different brand tires often give different ride qualities to the vehicle.)
- Bent or bound-up shock absorbers.
- Heavy-duty components installed on vehicle.
- Improper installation of cab mounts (grounding).

Other vehicle ride motions may be summarized as follows:

- Vehicle bounce -- the vertical motion of a vehicle on its suspension system, front and rear in phase. A low frequency "float," an intermediate frequency "kick."
- Vehicle pitch -- the out-of-phase vertical motion of the front and rear of the vehicle. A flat ride would be considered the opposite of a pitch ride.
- Vehicle roll -- the side-to-side rotation of the vehicle body about the front and rear axles.