An air suspension apparatus is disclosed for use with the fifth wheel connection between a tractor and semitrailer. The apparatus includes upper and lower frame sections that are connected by a hinge mechanism for relative pivotal movement. An inflatable air bag is operably disposed between the upper and lower frame sections, having a low ratio of effective surface area to internal volume and hence a very low profile. An air reservoir defined by tubular framework surrounds the air bag and has an internal volume approximating that of the air bag. The air bag and reservoir are connected by an air line with a very small cross sectional area as compared to the surface area of the air bag. The reservoir and interconnecting air line effectively damp vibrational energy in the air bag as the tractor and semi-trailer move over the highway.
