09 Tag Axle

Tag Axle Operation

A tag axle is installed on coaches longer than 40’ to distribute weight, improve ride, and add stability to the vehicle.

The tag axle is not a “lift” style axle. However, air pressure in the tag axle is controlled while making sharp turns, and when backing up, to reduce vehicle turning radius and prevent excessive wear on the tag axle tires.

While driving, tag axle air pressure is regulated by the drive axle height control valve. This allows weight on the tag axle to vary based on weight applied to the drive axle. When the turn signal is activated, and vehicle speed is below 20 MPH, pressure in the tag axle air bags is reduced to provide a tighter turning radius, and to prevent “scuffing” of the tag axle tires. Once the vehicle speed is above 20 MPH the tag axle air bags will return to their normal operating pressure.

When the transmission is placed in reverse gear, pressure in the tag axle air bags is also reduced to allow for tighter turns while backing the vehicle. Once the vehicle is driven above 20 MPH the tag axle air bags will return to their normal operating pressure.