Springs and Suspension Assemblies. Springs and suspension assemblies shall be: Of ample resiliency under all load conditions; Able to sustain the loaded vehicle without evidence of overload; and Designated to carry their proportional share of gross vehicle weight. Rear Springs. Rear springs shall be of a progressive type. Front Springs. If leaf-type front springs are used, the stationary eyes shall be protected by a full wrapped leaf in addition to the main leaf. Shock Absorbers. Two front and two rear double acting shock absorbers compatible with the manufacturer's rated axle capacity shall be provided.