Various embodiments of a crankshaft assembly with an insert are disclosed. The crankshaft assembly for an air compressor comprises a crankshaft with a first segment; a second segment having an outside diameter and a cavity extending into a distal end. The cavity comprises a first portion having a first inner diameter; and a second portion having a second inner diameter, wherein the second inner diameter is less than the first inner diameter. The crankshaft includes a linear passage in the second segment, wherein the linear passage does not intersect the cavity. The crankshaft assembly includes an insert having a first end with a first insert diameter and a second end having a second insert diameter, wherein the insert is sized to be matingly engaged in the cavity.