G.3.5. What is a 90° grooved nut?
The 90°-nut is used in combination with torque levers or special cone rings.
In combination with torque levers, shims of 0.1 mm thickness are used to center the unit perfectly in the bottom bracket shell.
The 90° nut is available in three different widths to make installation possible even for unusual combinations.
It also allows the combination with different cone rings. In this case, aluminum cone rings with smooth back side are used, as there is no torque to be transmitted on the left side.
The photo above shows a 90° grooved nut with a +2 mm cone ring with smooth backside.
The photo below shows a 90° grooved nut with 0.1 mm shims.
Grooved nuts for mountain-drives have a left hand thread, for speed- and high-speed-drive a right-hand thread.