My only experience with a dual is Airflow. I LOVE it. We spread so much less material with that spreader. Second season and its still like new. I have the factory optioned sides on it and pack close to 3 ton in it.
Diesel trucks with plows that are too heavy for them, and spreaders loaded too heavy for them too
Allis 645B with Protech HD 14'
64 Chevelle Tube Chassis drag car and some other toys