When sourcing a used lowbed trailer, you must prioritize the structural integrity of the main beam. Look for high-tensile steel (like Q345B or T700) that shows no signs of major welding repairs or sagging. Check the loading capacity (tonnage), typically ranging from 30 tons to 100+ tons, and ensure the deck length and width (often with outriggers for widening) meet your specific heavy-equipment transport needs. Additionally, inspect the suspension system (mechanical or air) and the axle brand (e.g., FUWA or BPW), as these directly impact maintenance costs and load stability.