remy:
American tractors usually have tandem drive axles with air bag suspension. You can let the air out of the bags but it won’t lift the axle up. Some dump trucks and heavy haul tractors that have an extra axle do have the option to lift that axle up when not needed. Some trailers have air bags but no lifting axles but most have the old metal leaf springs.
. . . Yeah, old being key . . . Currently pulling an old 1986 A-train!
Jeeze, how do they get away with running these old things now days 