6" x 2" V-Groove Ductile Steel Kingpinless Swiv Caster Heavy Duty,1500# Cap6" x 2" V Groove Ductile Steel Wheel Kingpinless Swivel Caster The Ductile Steel wheel provides extreme weight capacity for its size. The ductile steel is graphite rich, which is stronger and more durable than even our standard semi steel wheels. With a tensile strength of 45,000 PSI, you'll be hard pressed to find a job that needs a stronger wheel. The v groove allows this wheel to easy travel along integrated tracks. Tread: Solid Cast Ductile Steel