[serialk11r]

Today I decided I would try a bit harder to get a measurement on the pulley, and spent some time with my hand stuck in the tiny gap next to the motor to try and get a measurement. I can't be sure if I managed to get a reading of the actual diameter, but I got a 112.5mm on my calipers, which is including the belt wrapping around one side, so the pulley is at least 108.5mm in diameter.

Eyeballing it, there seemed to be a bit over 1cm of clearance between the tensioner and water pump, so adding 5-6mm to the radius should not be a problem. This should reduce the speed by 9%, decreasing pump power consumption by 30%, which should save me something around 100-200W while cruising depending on speed, and around 2hp at high rpm.

Can anyone make me a 119mm OD, 109 ish ID, 21mm wide plastic ring with a 3d printer? Nylon preferred, but frankly anything is probably fine. The pulley is smooth, it doesn't need grooves. Happy to give you money for your trouble of course.