John Deere 4066M · FLAIL MOWERS
For the standard 4066M hydro profile, the brochure’s 57 PTO hp and the book/manual’s unqualified 52 both exceed the FM62 family’s 45-PTO-hp maximum. The FM78’s 30–65 band remains numerically available, and both PTO references exceed FM2584’s 49 minimum. The remaining choice is about 70 versus 84 inches, blade configuration, reach and complete load—not a presumption that more tractor power approves every smaller mower.
By Acreage Equipment · Reviewed November 8, 2026 · Specification research, not a field test
PUT THIS GUIDE TO WORK
See published mismatches and the checks still needed.
BEST MATCHES FOR THE 4066M
9 of 23 flail mowers we track pass the published power, hitch and speed screen. Each still has a detail to confirm with the seller.
Flail mowerWoodMaxx
70″ cutting width, inches · 30–65 PTO hp · Y-blades only
Confirm the complete operating weight; a shipping weight cannot establish the attachment load.
Flail mowerWoodMaxx
70″ cutting width, inches · 30–65 PTO hp · Hammer blades only
Resolve the conflicting published specifications for the exact model revision.
Flail mowerWoodMaxx
70″ cutting width, inches · 30–65 PTO hp · Hammer blades only
Confirm rear remotes, hydraulic flow and pressure requirements.
Flail mowerLand Pride
72″ cutting width · 42–80 tractor hp · engine/PTO basis unspecified
Ask the manufacturer whether the horsepower range means engine or PTO power.
Flail mowerLand Pride
84″ cutting width · 49–80 tractor hp · engine/PTO basis unspecified
Ask the manufacturer whether the horsepower range means engine or PTO power.
Flail mowerFarmry
87″ cutting width · 30–85 HP (basis not stated) · official page and manual
Ask the manufacturer whether the horsepower range means engine or PTO power.
3 more possible options in the full comparison table.
THE DECISION IN NUMBERS
57 is a brochure-defined standard-model hydro reference. Unqualified 52 is retained, not relabeled HST. Land Pride’s engine/PTO basis remains unstated even where both interpretations have the same numerical result.
Scroll the table sideways on smaller screens.
| Product / configuration | Published power requirement | Qualified tractor comparison | Decision still needed |
|---|---|---|---|
| FM62 / FM62H hammer · 55-inch cut | 24–45 PTO hp | 57 is 12 above maximum; unqualified 52 is 7 above | Outside the published power band. A smaller deck is not an automatic option for a larger tractor. |
| FM78 fixed · Y or hammer · 70-inch cut | 30–65 PTO hp for either blade option | 57 is 8 below maximum; 52 is 13 below | Power range does not choose blade style; order the intended configuration and verify fixed placement. |
| FM78H hammer · 70-inch cut | 30–65 PTO hp; rear hydraulic circuit required | Same numerical range as fixed FM78 | Verify actual rear circuit; no settled cutting-edge travel follows from the page’s offset labels. |
| FM2572 hammer · 72-inch cut | 42–80 tractor hp; basis unstated | 57 and 52 PTO, and 65 engine, are inside numerically | Clarify basis and material demand; only 2 inches more cut than FM78, with different mounting geometry. |
| FM2584 hammer · 84-inch cut | 49–80 tractor hp; basis unstated | 57 is 8 above 49; 52 is 3 above; 65 engine also inside | Power-basis ambiguity does not flip this screen. Complete 84-inch hammer load and 96-inch overall envelope remain decisive. |
The FM62 family’s 45-PTO-hp ceiling applies to both its 55-inch hammer and Y configurations, including hydraulic versions. Both Deere references exceed it. This exclusion holds even though the 57-versus-52 source conflict remains unresolved; no lower-power workaround is inferred. FM78 and FM78H have a different 65-PTO-hp maximum. The current 65-hp engine label should not be compared to that PTO ceiling: the selected 57 PTO reference is 8 below it, while the unqualified 52 alternative is 13 below. Confirm the actual rating before purchase, but do not erase the documented upper limits.
FM78 cuts 70 inches, FM2572 cuts 72 and FM2584 cuts 84. The largest option adds 14 inches of cut over FM78, but its overall width is 96 inches and its mounting choices are centered or a fixed 10 inches right. Those figures are not hydraulic travel or proof of reach beyond this tractor’s tires. Both PTO references and the current engine label lie inside FM2584’s numerical 49–80 range, so the unresolved horsepower basis no longer changes the initial result. Ask for actual wheel spacing, gate clearance, permitted offset position and material demand before choosing the wider deck.
Fixed FM78 Y and hammer options share the same 30–65 PTO-hp band; the Y version does not have a lower minimum at this size. WoodMaxx describes different vegetation uses and says the purchased configurations are not interchangeable. FM78H adds hydraulic positioning, requiring a rear circuit whose type, flow and pressure are not settled by Deere’s total-pump number or remote-availability wording. FM25 uses separate rotor assemblies and fixed hitch positions. Its current catalog conflicts between 1.5- and 2-inch hammer capacity, so that unsettled value cannot justify a claim that FM2584 handles tougher material.
The standard 4066M brochure still gives 2,500 lb at 24 inches and 3,130 lb at the link ends, the same references as the smaller standard 4M models. FM2584’s 1,236-lb manual figure is a duckfoot-equipped unit, not the complete hammer machine; its separate 301-lb hammer rotor is not an add-on total. FM78’s 880-lb manual figure also lacks complete operating inclusions. Obtain the assembled mower, shaft, fluids and rake load with its center of gravity. The older Deere manual’s whole-machine 8,820-lb ballasted limit is not implement payload. Resolve actual hitch geometry, fixed WoodMaxx iMatch exclusions and PIN-matched ballast/axle limits.
Farmry rates the HFS87 at 30–85 hp without saying whether that is PTO or engine power, lists Category I and II, cuts 87 inches and weighs 1,299 lb with the shaft. The John Deere 4066M’s 57 PTO hp and 65 engine hp are both inside that range, so the basis does not change the result. Its published lift at 24 inches, 2,500 lb, carries that weight with 1,201 lb to spare; check front ballast all the same. Farmry rates the gearbox at only 50 hp, below this tractor’s 57 PTO hp; ask Farmry how hard it can be driven. The 87-inch cut is 3 inches wider than Land Pride’s FM2584. Farmry’s page listed it at $4,499 on November 14, 2026.
THE SCREEN, WITH ITS LIMITS VISIBLE
No pairing below is manufacturer-confirmed. “Preliminary” still requires implement limits, load center, ballast, hitch geometry and shaft checks.
Initial specification screen only. Scroll the table on small screens. Read the product page for every remaining check.
| Attachment | U.S.-linked brochure HST scope · 037BLV / eHydro 1520 reference · standard 4M · 4WD · open station57 PTO hp |
|---|---|
| Farmry LFS45 →355 lb · Net weight WITH PTO shaft, current LFS manual Rev 1.7 p18 | Published mismatchBoth engine (65) and PTO (57) horsepower exceed the published 35 hp maximum. |
| Farmry LFS53 →395 lb · Net weight WITH PTO shaft, current LFS manual Rev 1.7 p18 | Published mismatchBoth engine (65) and PTO (57) horsepower exceed the published 35 hp maximum. |
| Farmry LFS61 →421 lb · Net weight WITH PTO shaft, current LFS manual Rev 1.7 p18 | Published mismatchBoth engine (65) and PTO (57) horsepower exceed the published 35 hp maximum. |
| TMG Industrial TMG-TFM60 →650 lb · Product-page operation weight; manual gives conflicting 270 kg (about 595 lb) | Published mismatch57 PTO hp exceeds the manual’s 50 PTO hp maximum. |
| Farmry LFP47 →464 lb · 464 lb including PTO shaft on the product page; current Rev 1.3 manual lists 210 kg / 463.7 lb. Shipping weight is a separate 671 lb. | Published mismatchBoth engine (65) and PTO (57) horsepower exceed the published 45 hp maximum. |
| TMG Industrial TFMS50 →660 lb · Product-page operation weight: 660 lb. Manual structure weight: 300 kg (about 661 lb); shaft and fluid inclusion are not explicit. Shipping weight: 770 lb. | Published mismatch57 PTO hp exceeds the manual’s 50 PTO hp maximum. |
| WoodMaxx FM-54 · Y-blades →408 lb · Current 2025-and-newer manual p40 lists 408 lb product weight without stating shaft inclusion. Page instead says 410 lb mower-only plus a 39 lb shaft. Do not treat 408 lb as a verified complete operating assembly; confirm delivered Y-blade weight. Shipping page figure is 500 lb. | Published mismatch57 PTO hp exceeds the published 25 hp range. |
| WoodMaxx FM-62H · Hammer blades →860 lb · Current 2025-and-newer manual, printed p40 / PDF p41: 860 lb product weight; shaft/oil/packaging inclusion is unstated. Page instead lists 716 lb mower-only plus a 39 lb shaft. Shipping is separately labeled 860 lb. Do not treat the manual number as verified complete operating weight; confirm delivered hammer assembly. | Published mismatch57 PTO hp exceeds the published 45 hp range. |
| WoodMaxx FM-78H · Hammer blades →968 lb · Current 2025-and-newer manual, printed p40 / PDF p41: 968 lb product weight; shaft/oil/packaging inclusion is unstated. Page instead lists 804 lb mower-only plus a 39 lb shaft. Shipping is separately labeled 1000 lb. Do not treat the manual number as verified complete operating weight; confirm delivered hammer assembly. | Needs specification reviewConfirm rear remotes, hydraulic flow and pressure requirements. |
| WoodMaxx FM-62 · Hammer blades →774 lb · Current 2025-and-newer manual printed p40 / PDF p41 lists 774 lb product weight without shaft/oil/packaging inclusion. Page lists 641 lb mower-only plus a 39 lb shaft; shipping is separately labeled 800 lb. Retain these distinct bases and confirm complete operating weight for the delivered hammer assembly. | Published mismatch57 PTO hp exceeds the published 45 hp range. |
| WoodMaxx FM-78 · Hammer blades →880 lb · Current 2025-and-newer manual printed p40 / PDF p41 lists 880 lb product weight without shaft/oil/packaging inclusion. Page lists 710 lb mower-only plus a 39 lb shaft; shipping is separately labeled 900 lb. Retain these distinct bases and confirm complete operating weight for the delivered hammer assembly. | Needs specification reviewResolve the conflicting published specifications for the exact model revision. |
| Farmer-Helper FH-EFGC125 · Hammer blades →Operating weight unconfirmed · Complete operating weight is unverified. Current page: 576 lb “Weight” and 624 lb “Crated Weight.” Linked Rev 12-12-17 manual p23: 600 lb “Weight” and 635 lb crated. Product-weight shaft/oil/assembly inclusions are unstated. Keep these separate; do not use crate weight or silently choose one product figure as an operating load. | Needs specification reviewConfirm the complete operating weight; a shipping weight cannot establish the attachment load. |
| Farmer-Helper FH-EFGC155 · Hammer blades →Operating weight unconfirmed · Complete operating weight is unverified. Current page: 741 lb “Weight” and 789 lb “Crated Weight.” Linked Rev 12-12-17 manual p23: 720 lb “Weight” and 755 lb crated. Product-weight shaft/oil/assembly inclusions are unstated. Keep these separate; do not use crate weight or silently choose one product figure as an operating load. | Needs specification reviewConfirm the complete operating weight; a shipping weight cannot establish the attachment load. |
| WoodMaxx FM-62 · Y-blades →Operating weight unconfirmed · Complete Y-configuration operating weight is unverified. Current manual p40 gives 774 lb generic product weight without shaft/oil or blade-specific inclusion. Page gives 641 lb mower-only plus 39 lb shaft and separately 800 lb shipping. These bases conflict or lack scope; none substitutes for an assembled Y operating load. | Published mismatch57 PTO hp exceeds the published 45 hp range. |
| WoodMaxx FM-78 · Y-blades →Operating weight unconfirmed · Complete Y-configuration operating weight is unverified. Current manual p40 gives 880 lb generic product weight without shaft/oil or blade-specific inclusion. Page gives 710 lb mower-only plus 39 lb shaft and separately 900 lb shipping. These bases conflict or lack scope; none substitutes for an assembled Y operating load. | Needs specification reviewConfirm the complete operating weight; a shipping weight cannot establish the attachment load. |
| Land Pride FM2560 · hammer rotor →Operating weight unconfirmed · Manual p39 specifies 965 lb for the standard unit with a duckfoot rotor; the brochure lists 929 lb without a rotor/inclusion basis. The separate hammer-rotor assembly is 222 lb. No complete hammer operating mass or shipping mass is established. Do not add the rotor to an already rotor-inclusive unit weight or substitute these references for the operating load. | Needs specification reviewAsk the manufacturer whether the horsepower range means engine or PTO power. |
| Land Pride FM2572 · hammer rotor →Operating weight unconfirmed · Manual p39 specifies 1,040 lb for the standard unit with a duckfoot rotor; the brochure lists 1,040 lb without a rotor/inclusion basis. The separate hammer-rotor assembly is 261 lb. No complete hammer operating mass or shipping mass is established. Do not add the rotor to an already rotor-inclusive unit weight or substitute these references for the operating load. | Needs specification reviewAsk the manufacturer whether the horsepower range means engine or PTO power. |
| Land Pride FM2584 · hammer rotor →Operating weight unconfirmed · Manual p39 specifies 1,236 lb for the standard unit with a duckfoot rotor; the brochure lists 1,168 lb without a rotor/inclusion basis. The separate hammer-rotor assembly is 301 lb. No complete hammer operating mass or shipping mass is established. Do not add the rotor to an already rotor-inclusive unit weight or substitute these references for the operating load. | Needs specification reviewAsk the manufacturer whether the horsepower range means engine or PTO power. |
| Blue Diamond Heavy Duty 403740 →1763 lb · 1,763 lb (800 kg) in the Aug-2025 spec sheet (without PTO) and the Feb-2026 manual p49. Add the PTO shaft for the operating load. | Published mismatchBoth engine (65) and PTO (57) horsepower are below the published 75 hp minimum. |
| Farmry HFS87 →1299 lb · 1,299 lb (589 kg) including PTO shaft on the product page and in the HFS manual Rev 1.6, printed p17. | Needs specification reviewAsk the manufacturer whether the horsepower range means engine or PTO power. |
| Farmer-Helper FH-EF95 →330 lb · 330 lb retained, the heavier of the product page (325 lb) and the FH-EF manual p13 (330 lb); crated 360 lb. Neither says whether the included PTO shaft is counted. | Published mismatch57 PTO hp exceeds the published 45 hp range. |
| Farmer-Helper FH-EF105 →347 lb · 347 lb retained, the heavier of the product page (342 lb) and the FH-EF manual p13 (347 lb); crated 377 lb. Neither says whether the included PTO shaft is counted. | Published mismatch57 PTO hp exceeds the published 45 hp range. |
| Farmer-Helper FH-EF125 →390 lb · 390 lb retained, the heavier of the product page (390 lb) and the FH-EF manual p13 (383 lb); crated 438 lb. Neither says whether the included PTO shaft is counted. | Published mismatch57 PTO hp exceeds the published 45 hp range. |
Is an 84-inch fixed-position FM2584 more useful than the 70-inch hydraulic FM-78H?
Read the guide →FIELD GUIDETake the complete setup, not just a horsepower number, to the manufacturer.
Read the guide →FOLLOW THE NUMBERS
Research record reviewed November 8, 2026. Confirm the current manual and the exact revision supplied with your machine.