An Analysis of Recreational Off Road Vehicle Tire Performance Characteristics

Recreational Off Road Vehicles (ROVs) which are sometimes referred to as side-by-sides, have increased in popularity over the last decade. These vehicles are available in many different sizes and performance characteristics from a host of different manufacturers and also have a variety of different missions, just as there are many types of off road terrain. The United States Federal Government, through the Consumer Product Safety Commission (CPSC), has advocated and proposed vehicle handling and rollover resistance standards for the side-by-sides which have a top speed above 25 miles per hour (these are not defined as “low speed vehicles”). For the sake of repeatability, the proposed maneuvers are to be performed on a high friction hard surface (like asphalt) as opposed to the off road surfaces (i.e. grass, sand, dirt, mud. rocks, etc.) that these vehicles are designed to be operated on. Since ROV tires are designed for off road use only, their force and moment characteristics on an asphalt or concrete surface has not been studied in depth. This paper discusses a technical analysis of tire force and moment properties of two types of ROV tires, a bias ply and a radial ply both of the same size. The tests were conducted on an MTS Flat Trac III tire machine where slip angle sweep tests were performed at various vertical loads. Comparisons between the two ROV tire types, as well as comparisons to common passenger vehicle tires are made. Repeated step input of slip angle runs were also made to study how the ROV tire performance characteristics change as they wear during severe cornering in limit maneuvers.