This is hands down best money I ever spent! Belt is very happy in the sheaves. Set up with a stock contra and with the included red clutch springs. Very snappy take off with some wheelie action but is controlable. I was running the Treats 108 mm pulley halves but finding a belt was impossible and lots of vibration at top speed. None of that anymore. Would be a blessing if the pulley halves could be sourced alone.