Having thus described the invention, we claim:1. A rubber tired carrier adaptable for use with material handling equipment, the carrier comprising;a main body;a first frame adjustably connected to the main body;a second frame adjustably connected to the main body;a first wheel assembly set directly rotatably mounted to a first drive assembly set directly mounted on the first frame; and,a second wheel assembly set directly rotatably mounted to a second drive assembly set directly mounted on the second frame,whereby the first and second drive assembly sets are adjustable relative to one another to effectively expand or narrow an overall width of the carrier.2. The carrier as set forth in claim 1 wherein the main body has first apertures formed therein and the first and second frames have second apertures formed therein corresponding to the first apertures, the carrier having fasteners extending through selected first and second apertures to respectively connect the main body to the first and second frames.3. The carrier as set forth in claim 1 wherein the first wheel assembly set includes three tire assemblies having rims and the second wheel assembly set includes three tire assemblies having rims.4. The carrier as set forth in claim 1, wherein the wheel assemblies include a rim and a flexible material formed around the rim, the rim including a circular rim plate having a rim aperture formed therein for accommodating a hub, a rim cylinder having the rim plate positioned therein and generally triangular gussets extending from the rim cylinder to the rim plate.5. The carrier as set forth in claim 1 further comprising a chain drive assembly to link elements of the first and second wheel assembly and drive assembly sets.6. The carrier as set forth in claim 1, wherein the drive assemblies include a hub rotatably mounted within a wheel housing, a gear case connected to the wheel housing through a gear case adapter, a hydraulic motor connected to the gear case and a stub shaft connecting the gear case to the hub.7. A carrier adaptable for use with material handling equipment, the carrier comprising;a main body having first apertures formed on a first side thereof and second apertures formed on a second side thereof;a first frame having third apertures formed therein wherein the first frame is adjustably connected to the first side of the main body, first fasteners being positioned through aligned first and third apertures;a second frame having fourth apertures formed therein wherein the second frame is adjustably connected to the second side of the main body, second fasteners being positioned through aligned second and fourth apertures;a first wheel assembly set directly rotatably mounted to a first drive assembly set directly mounted on the first frame;a first means for connecting the first wheel and drive assemblies;a second wheel assembly set directly rotatably mounted to a second drive assembly set directly mounted on the second frame; anda second means for connecting the second wheel and drive assemblies;whereby the first and second drive assembly sets are adjustable relative to one another to effectively expand or narrow an overall width of the carrier.8. The carrier as set forth in claim 7 wherein the first and second wheel assembly and drive assembly sets incorporate skid steering principles.9. The carrier as set forth in claim 7 wherein the carrier has a generally square configuration when the overall width of the carrier is expanded.10. The carrier as set forth in claim 7 wherein the first and second wheel assemblies of the first and second drive assembly sets are rubber material mounted on rims.11. The carrier as set forth in claim 7, wherein the wheel assemblies include a rim and a flexible material formed around the rim, the rim including a circular rim plate having a rim aperture formed therein for accommodating a hub, a rim cylinder having the rim plate positioned therein and generally triangular gussets extending from the rim cylinder to the rim plate.12. The carrier as set forth in claim 7, wherein the drive assemblies include a hub rotatably mounted within a wheel housing, a gear case connected to the wheel housing through a gear case adapter, a hydraulic motor connected to the gear case and a stub shaft connecting the gear case to the hub.13. A material handler comprising;an upper having an extension for handling material; anda carrier supporting the upper, the carrier including;a main body;a first frame adjustably connected to the main body;a second frame adjustably connected to the main body;a first wheel assembly set directly rotatably mounted to a first drive assembly set directly mounted on the first frame; and,a second wheel assembly set directly rotatably mounted to a second drive assembly set directly mounted on the second frame,whereby the first and second drive assembly sets are adjustable relative to one another to effectively expand or narrow an overall width of the carrier.14. The carrier as set forth in claim 13, wherein the wheel assemblies include a rim and a flexible material formed around the rim, the rim including a circular rim plate having a rim aperture formed therein for accommodating a hub, a rim cylinder having the rim plate positioned therein and generally triangular gussets extending from the rim cylinder to the rim plate.15. The carrier as set forth in claim 13, wherein the drive assemblies include a hub rotatably mounted within a wheel housing, a gear case connected to the wheel housing through a gear case adapter, a hydraulic motor connected to the gear case and a stub shaft connecting the gear case to the hub.