Not true. Most modern cars have 4 wheel disks, exept for the very small economy cars. One exeption is the 1/2 ton Silverdos and Sierras from about mid-'05 up, they do have drums on the back. Most modern cars, though, use a considerably smaller, usually solid cast, rotor on the rear, as most of the braking is on the front. However, a truck is different as they require more braking on the rear, namely whan they are loaded.
