[Vern3039r]

Mowers are designed for 540rpm input, they may work ok at a lower rpm but won't have the same blade tip speed. If you are using a tractor at the upper hp range of an implement you won't notice using lower rpm as much as a tractor with the min hp.

I remember reading years ago that you want a torque rise when a tractor runs out of power and the rpms drop. You want a higher torque at a lower rpm than you are running so when it bogs down you actually get more power. If not you would have to start downshifting like an 18 wheeler going up a hill, if you're tilling you want to keep your speed up to get through soft ground not slow down.

 

[Vern3039r]

I agree with @mo1 to run the tractor at PTO speed for those implements that need it. The reason is that is how the implements are designed to run, if you run at 450rpm you are running 17% slower. When in heavy grass, 3' to 5', you will want to be at 540rpm and can bog down in heavier spots.

Like I said in post #5 you want the rpm to above the maximum power because the governor alone is going to do the job, you want more power available at a lower rpm so you don't stall.

If you have a 4052R you can get an economy PTO kit for it which lets you run an implement at 540rpm at a lower engine rpm