8" x 2" Ductile Steel Wheel AR Rigid Caster - 1250 Lbs Capacity overall-height-3-1/4 *Temperature range dependent upon bearings

*Temperature range dependent upon bearings selected

they can also operate off the track thanks to the tread on either side of the v-groove

While ductile steel is very hard

5" x 1-1/4" Steel Wheel Swivel Caster - Part # Q525001STL

8" x 2" Ductile Steel Wheel AR Rigid Caster - 1250 Lbs Capacity overall-height-3-1/4 *Temperature range dependent upon bearings8" x 2" Ductile Steel Wheel AR Rigid Caster Part # 28AR12 Manufactured from a high strength steel alloy, ductile steel offers improved capacity, durability & impact resistance compared to standard cast iron wheels. Ductile steel provides approximately 45,000 PSI tensile strength & features a thicker tread, spokes & hubs to withstand abusive industrial applications. Its moderately crowned tread design further reduces friction during rolling, swiveling