Page "Crankset" Paragraph 18

* Even newer designs have the bottom bracket spindle, usually hollow and larger diameter than is possible for bottom brackets with bearings held inside the bottom bracket shell of a bike frame, for reduced weight and increased stiffness, permanently attached to the right crank ( Shimano and others ) or the left crank ( Race Face ).

The left crank slides onto a spline and is tightened with one or more pinch bolts ( Shimano ) or is pressed onto a spline by a bolt on the bottom bracket spindle ( Race Face ).