BDS Suspension | 8" 4-Link Suspension System | 2014-2016 Dodge Ram 2500 4x4 Diesel. BDS Suspension adds to its industry leading lineup for the late model RAM 2500 4WD trucks with 8" 4-link systems. This new 8" 4-link system offers premium on-road comfort and superior offroad capability for the best all around performance out of your new 3/4-ton RAM trucks. The system converts the factory radius arm suspension to BDS's tried and true 4-link design for improved stability, wheel travel, and handling across all terrains. The 4-link design limits caster change to less than 1-degree of change throughout wheel travel for better handling, steering control, and overall driveability. The heart of the system are a pair of massive frame-mounted brackets precision welded and engineered to position the new upper and lower control arms for optimal suspension geometry for late model RAM trucks.