For front and rear hubs of all X1/9s from 1973. M20 x 1.5 with deformable top ring. The X1/9 factory torque specification is 216 Nm (159 lb/ft). Not applicable to the very first X1/9s that had M18 x 1.5 hubs. As the nut is staked into the hub shaft, you need to use a new one on each bearing change. Requires 30mm socket drive.

Also applicable to Lancia Beta Scorpion and Montecarlo S1 & S2.