Disc Harrow HP per foot of disc harrow width?

[MickeyDBC]

Are there any good rules of thumb for tractor horse power per foot of disc width along the lines of 5 PTO HP per foot of shredder? Need to get a bigger disc and wondering what a 70HP 4wd tractor will pull.

 

[MMalabama]

It depends on if you are talking 3pt or pull behind. Id say with 70 hp you can pull 7ft discs on the 3pt and 8ft hydraulic pull behind. I have a 40 hp Mahindra 4wd and I pull a very heavy set of Atlas 6.5ft discs 3pt. No doubt has to be in 4wd when going up hill or if the ground is wet.

 

[MtnViewRanch]

Are there any good rules of thumb for tractor horse power per foot of disc width along the lines of 5 PTO HP per foot of shredder? Need to get a bigger disc and wondering what a 70HP 4wd tractor will pull.

There are so many variables that it truly is impossible to get you an accurate idea without knowing pretty much all the circumstances-conditions. Just to give you an idea, A lot of people would say that my 75hp tractor would pull a 12'-14' disk. When in reality it only pulls my 8' disk. The tractor weighs in at 10,000+lbs with no loader.

I have an old pull type off-set disk with 22" pans, I've forgotten what it weighs, 3000lbs? :confused3: It's built with 3/8" & 1/2" frame material. I have rolling hills to do. On flat ground I don't even know its back there, get on the hills and on the 2 pass it works the tractor enough that I figure that a 9 footer may be to much at times.

I can pull a single pass on basically flat ground with our 12 footer as seen in the last picture, forget a 2nd pass or any hills what so ever.

So that is only an example, like I said, to many variables to actually give you an accurate idea IMO.

Just my :2cents:

 

[Phillip w]

That depends on how heavy the disc is and how deep you want to sink it in the ground. About 12 ft is going to be plenty. I got a 12 ft case disc and with the wheels up I can pull it with a 75ish hp tractor with no problem. It is pretty light. I got a 12 ft Krause disc and it is really heavy. With the wheels all the way up I can't pull it. It really digs in. I can pull it as long as I let the tires support some of the disc. Personally if I were in your shoes, I would not be afraid of a 10 or 12 ft pull behind disc. Make sure you have hydraulic couplings on your tractor so you can run the hydraulic cylinder on the disc.

 

[MickeyDBC]

That depends on how heavy the disc is and how deep you want to sink it in the ground. About 12 ft is going to be plenty. I got a 12 ft case disc and with the wheels up I can pull it with a 75ish hp tractor with no problem. It is pretty light. I got a 12 ft Krause disc and it is really heavy. With the wheels all the way up I can't pull it. It really digs in. I can pull it as long as I let the tires support some of the disc. Personally if I were in your shoes, I would not be afraid of a 10 or 12 ft pull behind disc. Make sure you have hydraulic couplings on your tractor so you can run the hydraulic cylinder on the disc.

That is along the size that I was thinking would work, tractor weighs about 9.5K with ballast and the loader. Just trying to break the soil up a little so we can drag it smoother with some cattle panels and railroad track, the old moving junkyard style. Going to rotate a mixed regenerative cover crop to try and get the soil back into condition before we start planting trees, just want to start with something a little smoother than I have now. I have an old 6 foot 3pt disk but it is not in the best of shape (needs more welding for cracks and some bearings on one row) and I am not sure that I want to mess with it right now, probably save it for a future project.

 

[MickeyDBC]

There are so many variables that it truly is impossible to get you an accurate idea without knowing pretty much all the circumstances-conditions. Just to give you an idea, A lot of people would say that my 75hp tractor would pull a 12'-14' disk. When in reality it only pulls my 8' disk. The tractor weighs in at 10,000+lbs with no loader.

I have an old pull type off-set disk with 22" pans, I've forgotten what it weighs, 3000lbs? :confused3: It's built with 3/8" & 1/2" frame material. I have rolling hills to do. On flat ground I don't even know its back there, get on the hills and on the 2 pass it works the tractor enough that I figure that a 9 footer may be to much at times.

I can pull a single pass on basically flat ground with our 12 footer as seen in the last picture, forget a 2nd pass or any hills what so ever.

So that is only an example, like I said, to many variables to actually give you an accurate idea IMO.

Just my :2cents:

Is the Mahindra turbocharged? I had a non-turbo diesel truck that would fall on its face at pretty much anything above sea level. We are at about 400 feet and pretty flat. Thanks for the pics, looks like you stay busy.

 

[smstonypoint]

Here's a spreadsheet from Iowa State that allows you to specify soil and tractor types* in calculation of HP requirements for various implements -- https://www.extension.iastate.edu/agdm/crops/xls/a3-28tractorsize.xlsx.

Steve

* The 4WD tractors are the large ag. tractors with front and rear tires of the same size.

 

[MtnViewRanch]

Is the Mahindra turbocharged? I had a non-turbo diesel truck that would fall on its face at pretty much anything above sea level. We are at about 400 feet and pretty flat. Thanks for the pics, looks like you stay busy.

Yes, it has a turbo, we're at 4000'up to 4140' elevation. If you think that you can pull a 12' offset disk weighing 4000-5000lbs at 8-9" deep for a second pass I sure would like to see that video. The 12 footer that I had pictured typically gets pulled with our D6. If you want to actually turn the ground and not just scratch the top 4-5 inches, even being flat I don't think you will want to go much wider than 10 foot with an offset disk. I have ZERO experience with tandem disks, all we have is a 6', 8' and 12' offset units, all built by Keilfer, all with 22" pans.

You didn't say how much ground you will be disking, but if it's more than 10 acres, I would be removing the loader. Just to much bouncing around, for me anyway.

I know that you can get away with a lot more width when you have wheels to set the depth, but why just scratch the surface? I can do the same by adjusting the cut angle with our sets, but why? I suppose maybe for a 3rd pass? Typically a second pass at 30* makes for a good finished job for me.

Anyway, good luck with your decision and what you end up with. :thumbsup:

 

[AWSubie]

R1s vs R4s will also make a difference with ground contact.

 

[MtnViewRanch]

R1s vs R4s will also make a difference with ground contact.

As far as my 7520, the actual square inches of tread gripping the ground is about 30% less with the R4s vs AG tires, which is huge. "One" of the reasons that I have my tractor ballasted to the weight that it is. (to get more traction) But the tractor would need more HP to pull more than what it now pulls in the conditions that I use it in.