The frame or unibody is the main structural piece of the vehicle. Though they provide similar functions, they have different designs and purposes. When combined with all the braking, steering and suspension systems, this is commonly referred to as the chassis, or undercarriage, of the vehicle.
The frame or unibody provides the structural strength of the vehicle and also a location and mounting points for other systems that make the total chassis. The frame design is the oldest, made of steel and designed so that the body of the vehicle is mounted on top. The unibody, on the other hand, differs from the frame in that it is actually stamped out as part of the body structure. Today’s automobiles most commonly use the unibody design because of its inherent ability to absorb energy during a collision.
The frame or unibody is not a separately serviceable item, so it does not require regular maintenance. Nevertheless, it is a good idea to periodically clean the undercarriage of the vehicle. Should your vehicle be involved in an accident, have the damage inspected immediately by a collision professional. Sometimes damage that appears to be merely cosmetic may wind up being more severe and affect your vehicle’s structural integrity, which could impact your car’s safety. Such damage may also affect wheel alignment, since proper alignment relies on a frame or unibody that’s within manufacturer’s specifications.