Thumb HP rule of thumb

[afish]

I have read here that the HP rule of thumb for a tiller or Bush hog is 5 HP per foot. Are they referring to engine or PTO horse power?

 

[IslandTractor]

I have read here that the HP rule of thumb for a tiller or Bush hog is 5 HP per foot. Are they referring to engine or PTO horse power?

I hadn't heard of the 5hp per foot rule but it must refer to engine HP. I ran a 4ft bush hog on a 21hp tractor with about 16 PTO hp and it was well matched. If I'd had a few more HP I could easily have run a 5ft hog in most conditions.

 

[Soundguy]

It should refer to pto hp.. but it is an 'ideal' figure. obviously you can run a hog on less than ideal power in many cases.

soundguy

 

[Tig]

My understanding of the rule is as Soundguy stated.
It's just a rule of thumb. I break it out of necessity with my 13 HP PTO. When the going gets tough I have to slow down to get the job done.

 

[greg_g]

Yup. Rule of thumb I work by is 5 PTO hp per foot of rotary cutter. Add a foot to that for rule of thumb finish mower size. But as mentioned, these apply to medium duty mowing. Adjust up if majority mowing is light duty, adjust down for heavy.

//greg//

 

[jbrumberg]

I will summarize what I read in "The Compact Tractor Bible": 2HP/1' of PTO HP for light duty rotary cutting and 5HP/1' of PTO HP for rotary cutters capable of smashing 2 inch diameter saplings. Jay

 

[RSKY]

I have choked down a 52-hp Ford 4600 with a six foot heavy duty bushog. It all depends on what you are cutting. I was in heavy grass riding down 2 inch saplins. The thirty year old mower is welded, bolted, and chained together but keeps on cuttin.

 

[flusher]

I have read here that the HP rule of thumb for a tiller or Bush hog is 5 HP per foot. Are they referring to engine or PTO horse power?

My Kubota B7510HST (21 hp engine, 17 hp pto) handled a 4-ft KK brush hog fine in weeds up to 2 ft tall. I had to take narrower cuts to handle 3-4 ft tall weeds.

My new Mahindra 5525 (55 hp engine, 45 hp pto) and a 6-ft Hawkline brush hog loaf along in tall weeds. My mowing time has nearly halved with the 5525.

 

[xlr82v2]

For tillers, I think a good rule of thumb is 3.5hp/ft PTO horsepower, at least for the soil we have here in southern Illinois.

For bushhogs, I agree that 5hp/ft is a good "rule of thumb", but I wouldn't feel handicapped with only 4hp/ft... you can always cut a half swath if you need to. I ran a 5' hog on my 8N, which is rated at 23hp on the PTO... and it did OK... considering the "too fast" gearing on the 8N. The 8N was never designed with a 'hog in mind.

 

[have_blue]

For bushhogs, I agree that 5hp/ft is a good "rule of thumb", but I wouldn't feel handicapped with only 4hp/ft... you can always cut a half swath if you need to.

To complicate things, HP ratings are all over the map.

Some tractors rate their PTO HP at an RPM that may not be realistic.

I think all tractor HP should be rated at the PTO, and at 540 RPM. That would be the honest way to do it.