Am I about to make a big mistake?

[Jackrabbit_Slim]

I have an acre of cleared land that I need to contour into a swale that will border a drainage ditch.

My basic plan is to rough cut it, break it up, and go to work with box blade and loader.

I don't know when this land was logged, but it's been at least four years, and it looks like they came in with something substantial to take the stumps out. There may or may not be some fair sized rocks lurking in the soil, which is a thin layer of very sandy loam covering some very sandy gravel.

Now, the issue I'm wrestling with. The local dealer advises that he wouldn't pull a subsoiler (at about six inches) with my tractor (Kubota B2710 HST... Yeah, the HST thing rears it's ugly head again.) I'm new to this HST stuff, and truth be told, I was so surprised to hear this, I never even thought to get his take on pulling a box blade.

Anybody with experience, advice, observations... I'd welcome your input.

Thanks,

Art

 

[DocHeb]

Don't know about using a Kubota HST, but my New Holland TC40D (with HST) pulls a Tractor Supply King Kutter Subsoiler quite nicely through our clay soil. I run it with the 3pt as low as possible, and it cuts ~12" down. Of couse, I'm running in Range I - Low.

 

[MarkV]

Art, interesting comment from your dealer. I can't recall ever hearing anyone recommending against heavy pulling because the tractor has a HST tranny. It certainly hasn't stopped me from pulling a boxblade as hard as the tractor is able to. With our compact tractors traction is normally the limiting factor and will stop your progress long before you run out of power. The transmission has pressure relief valves just as a loader or 3pt arms do which are designed to kick in when nearing the limits of the system before doing harm to the system. It would be interesting to hear more of the dealers thoughts on what the problem is.

MarkV

 

[MadReferee]

It sounds like your dealer is an old time farmer who thinks you should plow with only heavy gear tractors.

I have a B2710 and it will pull your subsoiler just fine. Use low range for best results. Your soil conditions should present no problems and if you do encounter a large rock that will not move you will stall out. I use a box scraper with the scarifiers all the way down and I hit softball to football size and bigger rocks all the time.

No big deal. Go for it.

 

[Moon]

I don't know your terrain up there, but, I always thought tractors were made for pullin stuff. I wonder if you have other dealers in your area you could see if they share the same concerns.
To me a sub soiler would be easier to pull than a box blade. It would be interesting to see what that dealer says if you tell him you also want to pull a box blade.
Moon of Ohio

 

[timb]

For what it's worth - and another dealer's opinion -

I am working with my dealer at the moment to configure either a JD 4710 or 4720. When we discussed usage and I mentioned that I would be definitely wanting to do some ag-style tillage (plow/disk/cultivators) on our 20 acres he immediately told me not to get a hydro. In his opinion a hydro was an excellent choice for so many things but not for long, steady, hard, pulling (tillage) work. Folks forget that while there is a minor PTO hp loss with hydros, due to running that pump, there is another entirely different loss factor at work. A hydro system will slip internally through fluid shear. Not only does that create additional power loss (drawbar hp) over and above the rated PTO loss, that power goes somewhere - it goes into heat. That can hasten breakdown of the fluid, increasing fluid shear, which can increase slippage... In theory it can be a escalating cycle if the system does not have sufficient cooling capacity for that duty.

That said - would it matter a lick with a modern compact? Since they don't do 'Nebraska Tests' on these compacts no one seems to know. For probably 95% of most folks intermittent heavy pulling duty it probably would be fine. For all-day at-the-max-power ground engagement like a farm tractor is expected to handle, maybe not. Could be my dealer is also somewhat old school, but note that he was 'down-selling' me to a less expensive solution via his recommendation.

YMMV

Tim

 

[Henro]

<font color="blue"> Folks forget that while there is a minor PTO hp loss with hydros, due to running that pump, there is another entirely different loss factor at work. </font>

I am certainly not an expert, but I've always thought the difference in PTO HP was due to the losses that show up as heat genereated in the HST system.

THe engine only produces so much power. That power is available to feed losses or do useful work. I think the "entirely different loss factor" you mentioned actually is the reason for the difference in PTO HP ratings in an HST tractor.

I guess what I am saying is that I think you are counting the same thing twice.

I have come to believe from reading posts here that the gear tractor is superior to the HST for tillage work, not because the HST can't do it, but more because the HST's advantages are no advantage at all for that application.

If I were going to get a tractor mainly for working the fields and pulling at constant speed, no doubt in my mind that I would get a gear tractor. For doing what I do on my little place, where nothing is flat and the steering wheel is hardly ever held in one position for more than ten seconds, HST excells. Durability does not seem to be an issue with either type transmission these days...

 

[theboman]

Where does on connect a PTO to a sub soiler? Hmmmm.

Now look at the world again.... Kubota sells tillers for their HST compacts. They sell box blades for the same tractor.

Putting sub soiler on a compact and running 6" deep is a pretty slow process when there's a lot of tree roots and it don't take a huge root to stop the tractor dead in it's tracks either... SLOW and easy.

 

[timb]

I believe that with most CUTs, the PTO is actually 'hard-wired' (via a clutch of course) to the engine. In other words, NOT a hydraulic motor run by a pump, but a gear-and-shaft affair. So, the measurable "hydro' hp loss there should only be from the fact that the same engine running the PTO shaft has another load hanging on it (that's not on the gear version of the same tractor) - the main hydro pump.

On the other hand, the hydro tractor's transmission is being run by a hydraulic motor, with flow produced by that pump. A fluid-drive design is not 100% efficient. (Of course, actually nothing is 100%, even a straight drive shaft with nee-plus-ultra bearings, there is always parasitic loss.) If drawbar hp numbers were given, you would see yet additional hp loss for a hydro vs. a gear. But how much loss %-wise would be conjecture since no one is testing for this.

Anyway - the additional loss of the fluid drive (that the CUT mfg's don't mention) is hp that doesn't just evaporate, it's going into producing heat, which could under worst-case situations, be a problem.

In the real world and not the lab, how hard would you have to push a CUT hydro before that's a problem? Who knows? I'm just passing along my dealer's comments - and they appear to sell everything from JD lawn tractors to 6000 series and up ag tractors to a wide range of customers.

Tim

 

[JerryG]

I believe that you would be OK to use the hydro for brief pulls of this type. It is amazing the amount of cooling that can take place, while you are turning around etc. Short pulls with a cooling turn around cycle should allow use. If you were doing several acres at once, then the hydro would not have time to expel the heat build up. If several acres at a time, is what you have in mind, then get a gear of some sort.