A side skirt blocks the airflow entering under the trailer from the side, reducing turbulence around the axle group and chassis components. Research shows that a properly applied side skirt alone can deliver fuel savings of between three and six percent; a "one size fits all" approach, however, quickly erodes that gain.
The Right Choice by Trailer Type
- Curtainsider and box body: A full-length skirt extending to the axle group delivers the highest gain.
- Tanker and silo trailer: Since access to the valve cabinet and discharge line is required, hinged or segmented partial skirts are preferred.
- Tipper: Due to site conditions, short, impact-resistant skirts with a flexible lower edge are appropriate.
- Container chassis: Systems with folding mechanisms that can be retrofitted to the chassis frame are required.
Material and Mounting Notes
Composite skirts stand out for lightness, aluminium skirts for ease of repair; a flexible lower edge (rubber/thermoplastic) prevents damage on ramp and speed-bump contact. Using vibration-damping connections between the skirt and the chassis during mounting prevents fatigue cracks. The smoothness and continuity of the skirt surface can matter more than its length.
References
- Durbin, T. D., Johnson, K. C., Jung, H. & Miller, J. W. (2021). Characterizing non-box trailer activity and aerodynamic devices for greenhouse gas emissions reductions. Transportation Research Part D: Transport and Environment, 98, 102763. DOI: 10.1016/j.trd.2021.102763
- Van Raemdonck, G. M. R. & Urila, I. (2019). A Study in Options to Improve Aerodynamic Profile of Heavy-Duty Vehicles in Europe. Sustainability, 11(19), 5519. DOI: 10.3390/su11195519