Rotary Mower Sizing and PTO Horsepower

[Parkranger]

I am trying to decide if there would be much benefit to reducing my rotary (brush) mower size to increase the horse power per foot and thus reduce strain on the tractor and possibly reduce mowing time. My L3430HST produces 27.5hp at the PTO, resulting in about 4.5hp per foot on my light duty BEFCO 72 rotary (brush) mower. The tractor can handle the weight of the mower just fine with the FEL, backhoe sub-frame and loaded tires, but it is a slow mow, about 2 mph, usually in L on the HST.

I am cutting pastures and meadows, so while the grass may get pretty tall between cuttings, saplings and brush is really not involved. Would trading down to a 60 rotary mower, resulting in about 5.5hp per foot really make that much of a difference. The R1 tires are set wide at 70 inches, so that is why the larger brush hog seemed to make sense.

I have also though about eventually getting a larger tractor, but I have also read that other members are able to bog down their machines even at 7hp per foot when cutting tall grass. I have read the 5hp per foot rule, but while having more hp per foot is never a bad thing, in practical terms, is increasing hp per foot going to really speed up mowing and prevent bogging?

Thanks in advance for your input.

 

[Earl Ohl]

I am trying to decide if there would be much benefit to reducing my rotary (brush) mower size to increase the horse power per foot and thus reduce strain on the tractor and possibly reduce mowing time. My L3430HST produces 27.5hp at the PTO, resulting in about 4.5hp per foot on my light duty BEFCO 72 rotary (brush) mower. The tractor can handle the weight of the mower just fine with the FEL, backhoe sub-frame and loaded tires, but it is a slow mow, about 2 mph, usually in L on the HST.

I am cutting pastures and meadows, so while the grass may get pretty tall between cuttings, saplings and brush is really not involved. Would trading down to a 60 rotary mower, resulting in about 5.5hp per foot really make that much of a difference. The R1 tires are set wide at 70 inches, so that is why the larger brush hog seemed to make sense.

I have also though about eventually getting a larger tractor, but I have also read that other members are able to bog down their machines even at 7hp per foot when cutting tall grass. I have read the 5hp per foot rule, but while having more hp per foot is never a bad thing, in practical terms, is increasing hp per foot going to really speed up mowing and prevent bogging?

Thanks in advance for your input.

If you're only cutting grass why don't you try sharpening the blades to try to make the edges a little more like a finish mower blade would be? The sharper the blade, the less horsepower the mower will take.

 

[KennyV]

Earl has the best idea....
Sharpen the blades, & you get a better mow and a Lot less effort for the tractor... Unless you are going to be cutting saplings and heavy brush you can get by with a very sharp blade.... It will take a lot of grinding but well worth the effort .... KennyV

 

[jeff9366]

Sharpening the blades is an excellent solution. You can sharpen dull blades with an angle grinder.

Block or chain up the mower. DO NOT TRUST 3-PT HYDRAULICS TO HOLD UP THE 'HOG.

You may find it cheaper to buy new, sharp mower blades than to pay someone else to grind yours. Check Agri-Supply.

Proper adjustment is also important.

Have you adjusted the 'hog so the front is about 1" lower than the back?

You want your 'hog to cut at the front only, then exhaust clippings out the rear.

If the blades are too flat, it mulches the clippings within the deck before clippings are exhausted out the rear, loading the mower.

You do not want the front too much lower than 1" because if you hit a stone the blade will be deflected too violently within the mower deck.


Is the tail wheel assembly greased and moving freely? Both the tail wheel in rotation around the axle and the castor swing within the strut?

 

[Xfaxman]

I am trying to decide if there would be much benefit to reducing my rotary (brush) mower size to increase the horse power per foot and thus reduce strain on the tractor and possibly reduce mowing time. My L3430HST produces 27.5hp at the PTO, resulting in about 4.5hp per foot on my light duty BEFCO 72 rotary (brush) mower. The tractor can handle the weight of the mower just fine with the FEL, backhoe sub-frame and loaded tires, but it is a slow mow, about 2 mph, usually in L on the HST.

I am cutting pastures and meadows, so while the grass may get pretty tall between cuttings, saplings and brush is really not involved. Would trading down to a 60 rotary mower, resulting in about 5.5hp per foot really make that much of a difference. The R1 tires are set wide at 70 inches, so that is why the larger brush hog seemed to make sense.

I have also though about eventually getting a larger tractor, but I have also read that other members are able to bog down their machines even at 7hp per foot when cutting tall grass. I have read the 5hp per foot rule, but while having more hp per foot is never a bad thing, in practical terms, is increasing hp per foot going to really speed up mowing and prevent bogging?

Thanks in advance for your input.

I think there is very little difference in power required to spin a 5' compared to a 6' mower, if it is not moving forward in grass. You could spin a 15' batwing with your tractor and mow a 5' wide strip of grass. When you move over to a wider strip it will bog down.

I would sharpen the blades as recommended and you don't have to mow the full 6' width, move over and mow 5' wide. It also makes a difference if you are mowing over the windrow left by the previous pass. If you are, you need to go the other direction around the field.

 

[wmonroe]

I would sharpen the blades as recommended and you don't have to mow the full 6' width, move over and mow 5' wide. It also makes a difference if you are mowing over the windrow left by the previous pass. If you are, you need to go the other direction around the field.

Great advice.

 

[Parkranger]

Thanks for all the advice and support, I never knew you could sharpen the blades (to a degree, still leaving a flat edge) of a rotary mower. This also confirms that switching down to a 5 foot mower really would not net that much as 'power'. Thanks