clutch will be 2 belts ... weakening or stretching. when straps are loose engine pulley just spins ... the gearbox stand still so I can change the speed. I have four different size pulleys with 340 mm, 220 mm, 140 mm, 70 mm. Each pulley is for two belts. transmission will be so small pulley-pulley belt-high. of the four dimensions that I have that I recommend that you use? I use 2 wheel tractor plowing, transport, planting, harvesting potatoes, etc.. I want to be versatile. will look something like yours. without primary gear ... engine - small pulley-belt-pulley higher - gearbox - 2 wheels