1VP40.1/2 Gates 1 groove variable pitch light duty sheave 3.75 (in) outside diameter, 1/2 (in) bore. Use with 3L, 4L, or 5L v-belts. Gates Product Number 7810-1408. Gates variable pitch sheaves are engineered for mechanical drive speed variations that are efficient, easy to install, and easy to adjust for your light-duty applications.