Rotary mower size

TGKY

Member

Equipment
L4701
May 24, 2018
31
3
8
US
I’m interested in opinions on minimum hp to run an 84” rotary cutter.

I recently purchased an l4701 up from an l3000 dt. I ran a 60” on the 3000. I see some Kubota packages putting a 72” with the l4701 but wondering if I can go 84” without problems.

I’ll be mowing around 40 acres of crp per year so it’s thick but mowing that much I want as big as I can trailer.
So do I need to stay with a 72 or can I go 84 without bogging down and having to run slow.
Also what gear are folks running in.
 

SDT

Well-known member

Equipment
multiple and various
Apr 15, 2018
2,230
382
83
SE, IN
I’m interested in opinions on minimum hp to run an 84” rotary cutter.

I recently purchased an l4701 up from an l3000 dt. I ran a 60” on the 3000. I see some Kubota packages putting a 72” with the l4701 but wondering if I can go 84” without problems.

I’ll be mowing around 40 acres of crp per year so it’s thick but mowing that much I want as big as I can trailer.
So do I need to stay with a 72 or can I go 84 without bogging down and having to run slow.
Also what gear are folks running in.
As always when sizing a mower one must first consider tractor PTO HP, type and thickness of cover, how quickly one wishes to travel while mowing, and tractor and mower weight.

First place to look is the recommended implement limitations in the Operator's Manual.

Don't have such specifications for L4701 in front of me at this time but can say that my HD 72" mower is all my L6060 wants at times.

SDT
 

mcfarmall

Well-known member

Equipment
Kubota M5660SUHD, Farmall C
Sep 11, 2013
606
543
93
Kalamazoo, MI
I'm not mowing jungle, but my M5660 (50hp @ PTO) spins my Land Pride RCD1884 just fine in low 4. Could run faster for sure if the ground was smoother. Grass isn't usually very tall, but thick.
 

PoTreeBoy

Well-known member
Lifetime Member

Equipment
L35 Ford 3930
Mar 24, 2020
740
252
63
WestTn/NoMs
With a wider mower, you have the option to slow down or overlap more in thick stuff. But, the wider a single gang gets, the more scalping you'll have on uneven ground (until you level it up :rolleyes:).
I think your L4701 has enough HP for a 7 footer, but it'll struggle lifting a single spindle like the RCR1884. Unless you find a good deal, I think you'll find the twin spindles are $$$.
Personally, I like to slow down in thick stuff so I can see obstructions. The ride is smoother and you get a better cut.
 

skeets

Well-known member

Equipment
BX 2360 /B2601
Oct 2, 2009
12,167
1,032
113
SW Pa
As I recall the old rule of thumb was 5 PTO hp per foot of implement. Hence I dont think it will have enough PTO hp to efficiently run a 84 inch deck. Will it run ,most likely but will it run with out tearing something up, and doing what you want it to do, that is the question and MHO is no
 

TGKY

Member

Equipment
L4701
May 24, 2018
31
3
8
US
Thank your for the replies. That rule of thumb is very helpful
 

TGKY

Member

Equipment
L4701
May 24, 2018
31
3
8
US
In follow up the specs say my 4701 has 39.3 hp at the pto(gear drive)
An 84” mower should require 35hp at 5hp/ foot. Am I thinking about that right or is that cutting it to close. I sure don’t want to break anything
 

hedgerow

Member
Jan 2, 2015
78
49
18
Malcolm NE
I think you would find a 84 inch mower on a L4701 in CRP would be a load. I did some CRP mowing with my MX-6000 and a Rhino TW-84 mower and it was a load on the MX-6000 in CRP. It handled well enough but I had to blow the rad and oil cooler out a lot.
 

SDT

Well-known member

Equipment
multiple and various
Apr 15, 2018
2,230
382
83
SE, IN
In follow up the specs say my 4701 has 39.3 hp at the pto(gear drive)
An 84” mower should require 35hp at 5hp/ foot. Am I thinking about that right or is that cutting it to close. I sure don’t want to break anything
Should be OK in light/moderate cover.

As I said, the 72" Woods cutter is all that my 53 PTO HP L6060 wants in much of the stuff that I cut.

Yes, I do cut close.

SDT
 

D2Cat

Well-known member
Lifetime Member

Equipment
L305DT, B7100HST, TG1860, TG1860D, L4240
Mar 27, 2014
10,177
1,273
113
40 miles south of Kansas City
Get a disc mower. Cut it and let it lay. Or you could bale it and give it away or feed you own animals. Not suppose to sell it unless there is a drought.

I think cutting 4' tall CRP with 7' chopper and 40 HP is too much mower!