| CPC F02B 75/282 (2013.01) | 24 Claims |

|
1. A piston apparatus, comprising:
a cylindrical piston body configured to slide in an opposed-piston, internal combustion engine cylinder having a bore diameter (D1); and,
the piston body including a biaxial bearing structure configured to define a biaxial wrist pin diameter (D2);
wherein, D2<0.5D1.
|