Rear Finish Mower Required PTO HP

trook · Jun 4, 2017

What is the rule of thumb for required PTO HP for rear finish mowers?

I know the rule of thumb for rotary cutters is 5hp at the pto per foot. However, I have found that I like to have closer to 7hp per foot at the pto for those tougher applications.

What do you suggest for normal pto hp for a finish mower, and what pto hp do you suggest for those tougher applications?

aczlan · Jun 4, 2017

trook said:
What is the rule of thumb for required PTO HP for rear finish mowers?

I know the rule of thumb for rotary cutters is 5hp at the pto per foot. However, I have found that I like to have closer to 7hp per foot at the pto for those tougher applications.

What do you suggest for normal pto hp for a finish mower, and what pto hp do you suggest for those tougher applications?

I would say about the same, we run a 7-foot finish mower on a tractor 35 PTO horsepower and in thick heavy grass it'll bog tractor down pretty well. If you were to go slower with a smaller horsepower tractor you would be fine.

Aaron Z

leonz · Jun 4, 2017

trook said:
What is the rule of thumb for required PTO HP for rear finish mowers?

I know the rule of thumb for rotary cutters is 5hp at the pto per foot. However, I have found that I like to have closer to 7hp per foot at the pto for those tougher applications.

What do you suggest for normal pto hp for a finish mower, and what pto hp do you suggest for those tougher applications?

============================================================================

Any integral or towed PTO powered implement is sized strictly using the gearbox provided by the manufacturer of that implement based on the estimated PTO horsepower needed for that implement.

There is a lot more to consider as a Hydrostatic/automatic transmission is going to be an energy hog simply due to the use of fluid power for the tractor and you lose power due to the heat created by the transmission and the oil pump or pumps used to power the tractor.

A mower of any type should be sized according to the tractors available horsepower or better yet to have the next larger engine frame size tractor for the work as the implemennt used will be less of a stress on the drive train of the tractor used

It is all going to come down to your wallets size and what you can afford to spend versus the rated horse power at the power take off of the tractor and whether you want an all purpose mower like a very good finish flail mower with three or four rows of side slicer knives or or a rotary cutter you intend to use on good turf. You have to keep in mind the power loss as you will or may very well invest in a rear finish mower that will have a central gearbox that will power the numerous mower spindles with V belts as many of them do.

Turbys_1700 · Jun 4, 2017

I pulled a 5 foot light duty Land Pride finish mower for 14 years with a 17 HP YM1700 Yanmar with no issues at all. Later I upgraded to a New Holland 1720 with 23.5 PTO HP and a heavy duty 6' Woods PRD 7200. The 1720 would struggle at times in heavy grass if my speed was too fast. The heavier duty Woods mower pulls much harder than the lighter duty Land Pride. I traded up to a Workmaster 50 last year so HP is a non issue.

The 5 HP per foot of cut is a good rule of thumb that I would expect to hold for lighter duty cutters. I would up that number to 7 for heavier duty units.

chim · Jun 5, 2017

Personal experience shows the deck weight / design have a lot to do with it:

Ford 1210, 13.5 PTO HP = Caroni 5' RFM is no problem, but Landpride 5' was way too much

Kubota B7500, 16 PTO HP = Caroni 5' felt like it wasn't even there, Landpride 5' was the upper limit

Kubota L3200, 25.2 PTO HP = 6' Landpride feels just right, can mow in 3rd range even on hills

kthompson · Jun 5, 2017

Type of grass also comes into play. We have a B2710 Kubota with 27 hp and hydro trans and use a 6 foot Bushog brand rfm. Works very well in high range cutting about 2 inches high on centipede and our zenith zoysia where not thick. But where the zoysia is thick it really bogs down. Have to really run slow there. Have had some bermuda sprigged for hay and mowing it with the Kubota and rfm last week at about three inches high. No issue most of the time but when hit thick crabgrasss which was at least 10 inches high it bogged way down. Part of that was the deck could not handle the amount of grass under it normal mowing speed but those spots were not normal.

Just for a comparison have two ztrs, one a Bushog using same spindles as the rfm and it is a 20 hp Kohler on 52 inch deck, would not have any smaller motor on that size deck and also have a Ferris with a 37 hp Kawaskia on a 60 inch (may be 61 or 62) and it also slows down in same zoysia but only for a couple of seconds. The 37 hp is an over kill for most of my mowing but it handles the zoysia when it is really thick very well.