Last week I watched Freightliner (they claim they make 80 percent of motorhome chassis) try and load their 45' bare chassis on a rollback trailer. The hitch would not have been dragging in the dirt if the tag axle had not deflated and the drive axle would have spun even sooner if it was inflated. A manufacture could spec a tag axle without the more expensive ride height valve and wiring that lets it dump the tag axle air in 1st, 2nd and reverse.
In looking at new, really heavy, big motor homes recently,I was surprised how many had steerable tag axles. Actually I should not have been surprised as taking the weight off a tag axle that has up to 17,000 pounds on it would severely overload the rear axle.
*Even though my tag axle lifts, I really raise it unless I'm doing multiple hard turns. In 80,000 miles I have not seen any extra wear on the tag tires plus they age out before they wear out. One that did not release the tags air pressure would not be a dealbreaker for me.
