Velocity ratio for pulley drive is given by [Where D1 = diameter of driving pulley, D2 = diameter of driven pulley, t = thickness of belt, S = total percentage slip]
1
\(\left( {\frac{{{D_1} + t}}{{{D_2} + t}}} \right)\left( {\frac{{100 + S}}{S}} \right)\)
2
\(\left( {\frac{{{D_1} + t}}{{{D_2} + t}}} \right)\left( {\frac{{100 - S}}{S}} \right)\)
3
\(\left( {\frac{{{D_1} + t}}{{{D_2} + t}}} \right)\left( {\frac{{100 - S}}{{100}}} \right)\)
4
\(\left( {\frac{{{D_1} + t}}{{{D_2} + t}}} \right)\left( {\frac{{100 + S}}{{100}}} \right)\)