RPM International offers three distinct types of crankshafts—Cast, 4130/5140 Forged with Nitriding, and the SAE 4340 Forged with Nitriding, which is our top of the line.

SAE Certified 4340 forged material is used for superior strength and its proven performance in the aircraft and aerospace industries. For increased strength these cranks are given a second heat treatment after rough finishing and then nitride hardened eliminating any deformation after leaving the factory.

RPM cranks are perfect for the racer who wants a forged unit without the price of a full race crank. These crankshafts are made from SAE Certified 4130, 4142, or 5140 materials and are nitride hardened for superior strength. These cranks use the part number prefix DG5 (for example: DG5-182D). Please consult your price list or the RPM catalog for the most popular street/strip applications.

RPM cast crankshafts are designed as a better than stock nodular iron OE replacement for domestic applications. Strong castings and a large selection of stroke and rod combinations make these cranks ideal for the street/strip racer. These crankshafts use part number prefix QT for example QT-039. Please consult your price list or the RPM catalog for your application.