What is the reason for the change-over?. My rayco poly chain has over 400 hours on it and is still in good shape. hope I did not just jinx myself. Does the unit perform better with the v-belts? I would think there would be more slippage with the v-belts. Have a couple of big carltons at work and the poly chains have close to 1000 hours on them. Had one break recently with a poor operator, kept bogging down the machine and running it with dull teeth, so I guess the belt gave up.