Polini Racing Evolution2 full cheek crankshaft with little end bearing for 12mm gudgeon pins - higher pre-compression and standard stroke. In order to keep the rotating mass low, plastic parts have been cast into the metal. The lower connecting rod bearing is also equipped with copper thrust washers. The extra hole at the upper rod end supplies the gudgeon pin with suitable lubrication under extreme loads. Polini quality for track & the seasoned tuner. Caution: should be used only in conjunction with the corresponding tuning cylinder kit or piston with 12mm gudgeon pin.