WHEELS
Wheels must have enough strength to carry the weight of the vehicle and withstand a wide range of speed and road conditions. Automobiles and light trucks are equipped with a single piece wheel. Larger vehicles have a lock ring (side ring) that allows for the easy removal of the tire from the wheel and. when in place. it provides a seat for one side of the inflated tire. A standard wheel consists of the RIM (outer lip that contacts the bead) and the SPIDER (center section that bolts to the vehicle hub). Normally the spider is welded to the rim. Common wheel designs are as follows:
Drop center
Semidrop center
Safety
Split
Drop Center Wheel
The drop center wheel (fig. 8-35) is made in one piece and is commonly used on passenger vehicles because it allows for easier installation and removal of the tire. Bead seats are tapered to match a corresponding taper on the beads of the tire.
Semidrop Center Wheel
The semidrop center wheel (fig. 8-36) has a shallow well, tapered-head seat to fit the taper of the beads of the tire. It also has a demountable flange or side ring. which fits into a gutter on the outside of the rim. holding the tire in place.
Safety Wheel
A safety wheel (fig. 8-37) is similar to the drop center wheel. The major difference is that the safety wheel has a slight hump at the edge of the bead ledge that holds the bead in place when the tire goes flat.
Split Wheel
A split wheel (rim) (fig. 8-38) has a removable bead seat on one side of the rim. The seat is split to allow for its removal so tires can be easily changed. Some bead seats also require the use of a lock ring to retain the seat. These wheels are used on large commerical and military vehicles.
