Brush Hog (Rotary Cutter) Buying Guide: Size, Weight and Gearbox

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Plan on 4 to 5 PTO horsepower for every foot of cutting width on a brush hog. A 5 foot cutter wants 20 to 25 PTO hp. A 6 footer wants 25 to 30, and more if you cut real brush.

Use PTO horsepower, not the engine number on the hood decal. A Kubota BX2380 is sold as a 21.6 hp tractor, yet Kubota’s brochure lists 17.7 hp at the rear PTO. That gap is normal, and it decides what fits.

Horsepower is only the first gate. Lift capacity, tractor weight, gearbox rating and driveline protection decide whether a cutter is a good match. This guide works through each one, using manufacturer specs and dated dealer prices we could confirm.

What is a brush hog, and how is it different from a finish mower or flail mower?

A brush hog is a rotary cutter. Two heavy swinging blades spin under a steel deck, driven by your PTO through a gearbox. The name comes from the Bush Hog company, but owners use it for every brand.

It is built for rough ground. Think pasture, fence lines, old fields and small saplings. The blades swing free on pins, so a rock or stump kicks them back instead of snapping them off.

A finish mower is the opposite tool. It uses a lighter deck and three fixed blades to leave a lawn look, and it cannot take brush.

A flail mower swings dozens of small knives from a horizontal drum. It mulches finer and throws less debris. It also costs more and needs more power per foot of width.

If your land is mostly grass you mow every two weeks, a finish mower may serve you better. If it is pasture and brush you knock down a few times a year, you want the rotary cutter.

What size brush hog do I need for my tractor?

The right size is the widest cutter your PTO horsepower, lift and tractor weight can all handle. Check the three limits in this order.

1. Find your PTO horsepower in the operator’s manual or the brochure spec table, not the gross engine hp.
2. Divide by 4 for grass and by 5 for brush. The result is the widest cutter in feet.
3. Compare your lift rating at 24 inches behind the lift points against the cutter’s weight. Include guards and the driveline.

Then check the tire track. A good cutter is a little wider than the outside of your rear tires. Otherwise the tires flatten a strip of grass the blades cannot reach.

Brush hog size for tractor hp

This table pairs tractor classes with the cutter width that manufacturer minimums and owner experience support. Treat it as a starting point and confirm the exact cutter’s minimum hp and weight.

Manufacturer minimums back up the 4 to 5 hp per foot rule. Bush Hog’s light BH110 series lists 15 PTO hp for the 44 inch BH114. The 56 inch BH115 needs 20, and the 68 inch BH116 needs 25.

Its standard BH210-3 series steps up. The 5 foot BH215 lists 25 hp, the 6 foot BH216 lists 30, and the 7 foot BH217 lists 50.

Frontier, Deere’s implement line, shows the same pattern in its RC20 literature. The 4 foot RC2048 is rated for 18 to 45 PTO hp. The 5 foot RC2060 covers 20 to 65, and the 6 foot RC2072 covers 25 to 65.

That Frontier sheet is dated 2011, so check the current Deere page before you buy. Land Pride lists its RCR12 series for 20 to 60 hp tractors. Woods rates the BB60.30 for 25 to 50 PTO hp and the BB72.30 for 30 to 65.

Bush Hog’s BH200 manual adds a warning most buyers never hear. Too little power can damage the tractor engine. Too much can damage the cutter by overpowering it in heavy cutting, so stay inside the published range at both ends.

Still choosing the tractor? Start with what size tractor you need by acreage and job, then come back for the cutter.

Why speed and conditions change the math

Owners adjust the rule for the job. Thin grass may need only 4 hp per foot. Thick brush may need 6.

Ground speed matters as much as horsepower. Bush Hog’s manual gives a normal range of 2 to 5 mph. Owners report the low end in thick stuff, and cutting less than full width keeps the engine at rated PTO speed.

Light, standard or heavy duty: what do the duty classes mean?

Duty class is the cutter’s strength: deck steel, blade size, gearbox and the biggest stem it is rated for. There is no industry standard label. Woods calls its mid line “Standard Plus” and Bush Hog uses series numbers, so read the specs and not the name.

The grouping below is our own way of sorting the market. The specs inside it come from the manufacturers’ current pages and manuals.

Rated capacity is the largest stem the maker says the cutter can handle. It is not what the cutter should do all day.

A 2 inch rating means the occasional sapling, not a stand of them. If you regularly face stems over 1 inch, step up a class.

Weight climbs fast as you move up, and Bush Hog’s own numbers show it. A light 5 foot BH115 is about 500 lb. The standard BH215 is 750 lb, and the heavy BH315 is 1,030 lb at the same width.

That weight is why a heavy duty cutter does not suit a small tractor, even when the PTO could turn it. A heavy cutter lifts the front end. Bush Hog’s manual requires 20 percent of total tractor weight to stay on the front axle at all times.

What does the gearbox horsepower rating mean?

The gearbox rating is the most horsepower the gearbox is built to carry. It is a ceiling, not a requirement. A gearbox that is too small fails when a stump hit sends a torque spike through it.

Owners often confuse it with the minimum hp. Both appear in the same spec table, and they are different numbers.

Bush Hog’s 56 inch BH115 carries a 60 hp gearbox and lists a 20 hp minimum. Its BH216 lists a 65 hp gearbox and a 30 hp minimum.

Woods lists a 65 hp gearbox on the BB60.30. Oddly, it lists 60 hp on the wider BB72.30.

Keep the rating clearly above your PTO hp. A 60 hp gearbox on a 55 PTO hp tractor leaves almost no margin for shock loads.

Ratings are not measured the same way across brands. Bush Hog’s spec sheet says its rating is based on field performance, and Woods says the same about its field testing. Compare within a brand, and treat cross brand numbers loosely.

Gearbox warranties are the clearest signal of confidence. Bush Hog and Woods both list a 10 year limited gearbox warranty on current single spindle cutters. Land Pride’s site mentions 5 years on the RCR12 while dealer pages still say 3, so ask which applies.

Check the oil before the first mow and every season after. Bush Hog and Rhino manuals both call for EP80W-90 or EP85W-140 gear oil. Both say to check the level with the cutter sitting level.

Capacities are small. The BH215 holds 2.1 quarts and a Rhino RH115 holds just under a quart.

A quart of Valvoline 80W-90 gear oil tops up a light duty gearbox. Confirm the grade in your own manual first.

Shear bolt or slip clutch: which driveline protection do you need?

A shear bolt is the cheap, simple choice. A slip clutch is the convenient one. Both exist because something must give before the gearbox does when the blades hit a stump.

Shear bolt

A shear bolt is a soft bolt through the driveline yoke that snaps when torque spikes. You replace it and keep going.

It costs almost nothing to own. You do need to carry spares and a wrench, or you walk back to the barn.

The grade is not a matter of opinion. Rhino’s RH series manual says to install a grade 2 bolt only, 1/2 by 3 inches. It warns that a stronger bolt “will result in driveline failure and will void warranty.”

Bush Hog’s BH200 manual names a different animal. Earlier BH215 and BH216 models take a metric 8 by 50 mm class 8.8 bolt. The Rhino RH series manual shows how specific these instructions get.

So use exactly what your cutter manual names, in grade, diameter and length. If yours calls for grade 2, a pack of grade 2 shear bolts in 1/2 inch keeps you mowing. Check the length against your yoke, since 3 inch and 3 1/2 inch bolts both exist.

Slip clutch

A slip clutch uses friction discs and springs. Under overload the driveline slips, then grips again. Nothing breaks.

Owners say it adds roughly $100 over a shear bolt model. Bush Hog, Rhino, Land Pride, Woods and King Kutter all offer one. Woods and the heavier Bush Hog series make it standard.

It needs a yearly check, and Bush Hog’s procedure is simple. Loosen the spring nuts a third of a turn, then engage the PTO at idle for 2 to 3 seconds so the clutch slips without turning the blades. Retighten to the original spring length.

Skip that and a clutch left outdoors can rust solid, so it never slips. Set it too loose and it slips in normal work and burns the discs.

A slip clutch is the better pick for rocky ground, stumps or work far from home. A shear bolt is fine on clean pasture. Plenty of long time owners say neither is clearly better.

If your used cutter came without a driveline, a VEVOR Series 4 PTO shaft is a common replacement. Measure collapsed and extended length on your tractor first. A shaft that bottoms out on a lift will wreck the gearbox.

A VEVOR 1 3/8 inch PTO slip clutch can add protection to a shear bolt driveline. Confirm the spline count and shaft size match before ordering.

Do you need an overrunning clutch on a tractor without an independent PTO?

Yes. If your transmission and PTO share one master clutch, run an overrunning clutch (ORC) between the PTO stub and the driveline. Bush Hog’s and Rhino’s manuals both state this as a requirement, not a suggestion.

An ORC works like a bicycle freewheel. It lets the heavy blade carrier coast without driving back through the PTO.

Without one, the spinning cutter pushes the tractor forward when you press the clutch to stop. The AEM safety manual bound into Rhino’s book calls this the flywheel effect. Common examples are the Ford 8N, 9N and 2N and the Ferguson TO series.

Owners add that many older 6 speed New Hollands and other transmission driven PTO tractors need one too. Our Ford 8N buyer’s guide covers that tractor’s PTO setup.

On a live or independent PTO, most owners skip it. Kubota’s BX80 brochure lists a live independent PTO with a hydraulic clutch, so a BX does not need one.

A few owners of bigger tractors run one anyway. It spares the PTO clutch pack from a heavy 6 foot cutter at shutdown.

An ORC is not a slip clutch. It does nothing for stump hits. Its only job is to let the blades coast.

For a Ford 8N, 9N or 2N, there is a C670F overrunning PTO coupler. It has limited review history, so treat it as one option and verify the fit.

For other non live PTO tractors, a 1 3/8 inch 6 spline overrunning clutch slips onto the stub shaft. Make sure the driveline still has enough overlap once the ORC adds length.

Which features matter: stump jumper, blades, tail wheel, guards and hitch?

Five features separate a cutter you will like from one you will fight. Guards come first, because they are your safety gear.

Front and rear chain guards

Chain or rubber guards close the gap between the deck and the ground. Purdue and Ohio State Extension both say chain guards reduce objects thrown from under the mower. Both say to keep them in place and replace worn ones.

The numbers explain why. Bush Hog’s and Rhino’s manuals warn a rotary mower can throw objects 300 feet or more, and tell you to keep bystanders that far away. Penn State’s ag safety material puts thrown object speed at up to 200 mph.

Buy a cutter with both front and rear guards, or add them. Light duty cutters often ship with a front rubber deflector and rear band, with front chains optional. Read the Ohio State Extension rotary mower safety sheet before your first season.

Stump jumper

A stump jumper is a dished plate or pan under the center of the deck. The blades bolt to it, and it lets the cutter ride over a stump instead of catching the gearbox shaft.

Land Pride uses a 10 gauge stump jumper on the RCR12. Bush Hog uses a formed pan on the BH110 and an oval carrier on the BH210-3. Any cutter you take into brush should have one.

Blades

Light duty cutters use 1/2 by 3 inch blades. Standard and heavy cutters step up to 1/2 by 4 inch. Thicker, wider blades carry more momentum through saplings.

Blade hardware is serious. Bush Hog’s and Rhino’s manuals call for 600 foot pounds on the blade nut and 450 on the pan nut. Both are rechecked after the first 8 hours.

That is beyond a normal shop torque wrench, so plan on a dealer or a multiplier for blade work. Both manuals also say to replace blades in pairs with new bolts and nuts. Never weld or straighten a blade.

Tail wheel

A tail wheel supports the back of the deck and sets cutting height. It keeps the cut steady on rolling ground.

Most 4 to 6 foot cutters carry a single laminated tire that cannot go flat. Frontier offers dual wheels only on its 7 foot RC2084.

3 point versus pull type

A 3 point cutter mounts on your Cat 1 or Cat 2 hitch and lifts for transport and turns. A pull type rides on its own wheels behind the drawbar.

Pull types are for wide cutters and big tractors. Small tractors almost always want a 3 point unit. Most 4 to 6 foot cutters are Cat 1, and Bush Hog’s 7 foot BH217 moves to Cat 1 or 2.

Can a sub compact tractor run a brush hog?

Yes, a sub compact can run a 4 foot light duty cutter, and that is usually its limit. A 5 foot cutter is a stretch. A 6 footer is too heavy.

Take the Kubota BX2380. Kubota’s BX80 brochure lists 17.7 PTO hp and a Cat 1 hitch. Lift is 680 lb at 24 inches behind the pin, and at 4 hp per foot the PTO supports about 4.4 feet.

Lift is the tighter limit. A Bush Hog BH114 (44 inch) is about 400 lb. A Land Pride RCR1248 is dealer listed at 413 lb with guards, so both fit under 680 lb with room for the driveline.

A 5 foot standard duty cutter does not. Bush Hog’s manual says the hitch must lift at least the cutter’s weight, and the BH215 is 750 lb. That alone rules it out on a BX.

Owners add two practical points. BX hitch arms are short and spread less than on larger compacts. A 24 hp class tractor with a 4 footer also feels slow uphill.

One old forum post quoted a 42 inch and 300 lb limit from a BX manual. We could not confirm it, so check your own manual’s implement section.

Our list of the best sub compact tractors notes which models have lift to spare. For service on this model, see the Kubota BX maintenance guide.

How much does a rotary cutter cost, and which brands should you look at?

A new 4 to 5 foot cutter from a major brand runs about $1,750 to $3,700 at dealers in October 2026. Light duty units sit at the low end and standard duty at the top. A 6 footer adds a few hundred dollars.

These are dealer asking prices from listings we checked, not manufacturer list prices. Freight, setup, tax and the slip clutch option all move the final number.

Here is how the brands sort out. Bush Hog and Woods are the premium names, with 10 year gearbox warranties, heavier decks and prices to match. Land Pride is Kubota owned and usually costs less for a light duty cutter.

Frontier is Deere’s dealer line, built to pair with Deere compacts and the iMatch quick hitch. Rhino’s current single spindle line is the RH100 and RH200. Its specs match Bush Hog’s BH110 and BH210-3 almost number for number, since both belong to Alamo Group.

King Kutter and Titan are the budget brands sold through farm stores and online. King Kutter offers a 40 or 60 hp gearbox on the same 5 foot deck. A shear pin is standard and a slip clutch is optional.

Titan’s Standard Series 4 footer lists a 40 hp gearbox, 11 gauge steel, 440 lb and a 1 year warranty. We could not confirm the 5 foot model’s current specs or price on Titan’s site.

Budget cutters are a fair deal for grass and light brush. The tradeoff is usually a lighter deck, a smaller gearbox, optional chain guards and a shorter warranty.

Used cutters make sense because they are simple machines. Frontier and Land Pride units a few years old turn up at $1,300 to $2,700 in dealer listings.

What should you inspect when buying a used rotary cutter?

Inspect the gearbox, driveline and deck before you talk price. Those are the expensive parts, and a seller cannot easily hide their condition.

1. Check the gearbox for oil weeping at the input and output shaft seals.
2. Pull the fill plug and look for milky oil, metal flakes or a dry box. Rhino ships its gearboxes empty, so dry is normal on a new unit. On a used one it is a red flag.
3. Spin the blade carrier by hand and feel for roughness or play in the output shaft.
4. Rock each blade and check the blade bolts and holes for wear. Blades should swing, not wobble.
5. Look under the deck for cracks, welded repairs and thin spots along the sidebands and skids.
6. Confirm the front and rear guards, the driveline shield and the gearbox shield are present.
7. Check the driveline type. A slip clutch should turn freely by hand with the springs loosened, not sit rusted solid.
8. Read the model plate and look up the gearbox rating, minimum hp and weight before you load it.

Walk away from a cutter with missing guards unless the price covers replacing them. A cracked gearbox housing or a bent blade carrier is also a reason to pass.

What mistakes do owners make with rotary cutters?

Most problems trace back to a cutter that is too big, missing guards or the wrong shear bolt. Here are the usual ones.

• Buying too big. A heavy cutter wags the tractor instead of the other way around. Weight matters as much as hp.
• Using engine hp instead of PTO hp. The gap is often 3 to 5 hp on a compact, which is a full foot of cutter.
• Running without guards. Chain guards, deflectors and the PTO shield stay on. Never carry a passenger.
• Using the wrong shear bolt. A harder bolt passes the shock to the gearbox and can void the warranty. One that is too soft shears all day.
• Skipping the overrunning clutch on a tractor whose PTO shares the transmission clutch.
• Mowing too fast in thick growth. Slow the ground speed and keep the engine at rated PTO rpm.
• Cutting too low. The deck rides on its skids and wears them out, and it throws more debris. Bush Hog’s manual says to raise the cut to 6 inches where thrown objects are a risk.
• Forgetting front ballast. A rear cutter lightens the front end. Our free ballast calculator helps you keep 20 percent of the weight up front.
• Never checking gearbox oil. A quart of gear oil is cheap. A gearbox is not.

The box blade buying guide uses the same lift and weight check. The rest of the attachment lineup is in our implements section.

Bottom line

Size a brush hog by PTO horsepower at 4 to 5 hp per foot. Then confirm your lift capacity and tractor weight. Sub compacts belong with a 4 foot light duty cutter, and compacts do well with 5 or 6 feet.

Pick a gearbox rated above your PTO hp. Choose a shear bolt or slip clutch and use the exact bolt your manual names. Add an overrunning clutch if your PTO is not live, and keep every guard on the machine.

Frequently asked questions

What is the difference between a brush hog and a rotary cutter?

Nothing, in everyday use. Bush Hog is a brand. Owners use the name for any rotary cutter, the way people say Kleenex for tissue.

How many feet of cutter does a 25 hp tractor pull?

A 25 PTO hp tractor handles a 5 foot cutter, which is exactly the minimum Bush Hog lists for its BH215. If 25 hp is the engine rating, your PTO hp is closer to 20. Look at a 4 foot or a light duty 5 foot unit instead.

Can I use a 6 foot cutter on a 30 hp tractor?

Yes in grass, at a slow ground speed. Bush Hog lists 30 PTO hp as the minimum for its 6 foot BH216. Woods lists 30 for the BB72.30.

You are at the bottom of the range, so thick brush and slopes will bog it. Check lift too, since those cutters weigh 850 to 880 lb.

Do I need a slip clutch if my cutter has a shear bolt?

No. Either one protects the gearbox. A slip clutch is easier on rocky ground because you do not stop to replace a bolt.

How high should I set the cutting height?

Set it as high as the job allows, and higher over rough ground. Most cutters adjust from about 1 1/2 to 12 inches. Cutting too low wears the skids and throws more debris.

Is a heavy duty cutter worth it for a small farm?

Only if you regularly cut stems over 2 inches and your tractor has 35 PTO hp or more. Bush Hog’s 5 foot BH315 lists a 35 hp minimum and weighs 1,030 lb. On smaller tractors that weight adds cost without helping.

How often should I change the gearbox oil?

Follow the schedule in your cutter manual. Bush Hog says to check the level every 8 hours of operation. Change the oil if it looks milky or dark.