AEV 4.5″ High Capacity Coil Springs are a direct fit upgrade for customers with an AEV 4.5″ DualSport SC Suspension System. Designed with the overlander in mind, these frequency-tuned, progressive rate coil springs provide the increased load carrying capacity necessary for heavily loaded vehicles, while still offering exceptional ride quality, handling and off-road articulation.These coil springs are only available as a matching set of front and rear springs in order to preserve optimal vehicle handling dynamics. The relative rate/frequency of the front coil springs vs. the rear springs is a crucial part of safe vehicle handling. Because of this, AEV increases the rate/frequency of the front springs in order to maintain an appropriate relationship with the rear springs, across the entire range of rear-biased loading.