My tool box is loaded up no gravel bags yet but soon. Maybe 250 lbs in tool box tires aired down to 50 f 40 r. Remember this is a regular cab long box tradesman. Ride is firm and ok on smooth roads . The good firm seats help a bunch. But on rough broken roads it’s a bit harsh. 300 lbs of gravel bags will give me some help. Like hauling a 4 wheeler and also help with traction in the snow and ice to come. This is a 1 ton truck and rides like it. I would not want to make it any worse. Thanks for all the help