1VP65 1.3/8 Gates 1 groove variable pitch light duty sheave 6.5 (in) outside diameter, 1-3/8 (in) bore. Use with 4L or 5L v-belts. Gates Product Number 7810-1839. 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.