Geared trannys-more low end torque than hydro ?

johnbilt · Sep 8, 2004

Hi

The operator has to adjust technique depending on what you are operating. I was loading heavy 2-3" rock with my geared 990 yesterday.

I use 4WD, about 2000 rpm, a little momuntum, and scoop the loader as I get under the rock. I usually use A range/3rd or B range/1st. The B range is preferable because I can reverse quickly without changing ranges.

This gear combo gives me enough momentum to drive under the rock with the FEL level. As the wheels just start to spin, I curl the bucket and drive forward to fill the bucket. In goes the clutch, and I hit reverse. I may jab a little extra throttle or raise the FEL to adjust engine load / traction. Generally this combo will not stall or lug the engine. The tires spin first. Adjust gearing / rpm as necessary to get this combo.

I try to avoid spinning excessively, so that I don't make a rough hole. This is obviously easier on rock than slippery mud.

I'm certain that a hydro model will do an equal job. It sounds like the load match feature does a lot of this coordination work for you. In either case, I would suggest that operating the FEL during the approach and loading will make a huge difference in the proper technique for either machine.

In other words, it is possible to use either trans incorrectly and stall the machine. I don't think the low end torque is the deciding issue for a similar hp and weight.

My 2 Pennys,

John

Soundguy · Sep 8, 2004

( We can have a little race. I'll be using my loader as the scoop method )

Considering that is an apples to grape comparison.. I won't even comment on that argument further.

Soundguy

Soundguy · Sep 8, 2004

( Some of us come from a farm background. We might use several thousand gallons of diesel fuel a year through our machines. At that scale, efficiency is a _very_ important part of the picture. )

Well said.

( Check out what happened to the hydro tractors that were introduced in the '60s.) )

That's my biggest issue with an HST tractor. Longevity. I have a gear tractor that is nearly 58 years old.. same seals.. etc. And if that gear tractor brakes.. I have a very easy manual.. and all it is is gears, shafts and seals.. just put them in in the right order and it works.. and if it doesn't.. it is very easy to see what is keeping it from working.. especially since the whole top of the tranny cover comes off, exposing all gears, shifter collars and rails.

I'm not knocking hst tractors... I just don't like the idea of looming repairs on the horizion.. that I really can't do on the dirt floor of my barn. Whereas on the other hand.. I feel fine about pulling apart the innards of my antique geared iron and rebuilding it in the field. Heck.. the oem shop manual shows the engine hanging from a tree in a field while it is being rebuilt.. and that was the instructions from FORD! I can't imagine rebuilding an hst tranny while it is swinging from a tree. I also have big concerns about the working lifespan of an hst tranny.. where the bulk of the working parts are seals.. and we all know what happens to trannies thet rely on hyd pressure to engage things.. when seals leak.. pressue is lower, and things don't engage? How long will todays hydro's last before needing repair? 20ys? Probably.. 40 ys? I think that is wishfull thinking.. yet all my geared tractors are 50 ys old or better ( except my cub ).. and the trannie gears and bearings are in top condition.

Besides.. I looked at a shop manual that a NH mechanic had for an hst tranny... and well... I'm glad I don't have to repair them...

( Why does it bother you that others choose something different? Why riddicule someone who enjoys using a rear scoop on his Ford N? What pleasure does that bring you?
)

It is one of those 'fanatic' things. From what I've seen, those people can't except any viewpoint other than their own. Even in situations, where you can 'see' their point, yet still disagree, they aren't happy. Kind of a 'one way / my way' thought pattern. How else do you get someone to strap a bomb to themselves and run out into a crowded street and blow people up? ( "fanatiscism" it works! )

Soundguy

_RaT_ · Sep 8, 2004

Paul, interesting you find my comments be they humorous or not to be so inflammatory yet don't consider comments like "......give me a shuttle/gear/powershift anyday. Anything but hydro" or "when the hydro bypasses, I'll grab another gear and continue on my way." or "you couldn't give them a hydro" to be perfectly legimate comments with no sense of bias. To each his own. If a manual toots your horn, thats great. Gear drives are more effective at utilizing the engines HP. If that is important as it would obviously be to folks who use large quatities of fuel, the choice should be pretty obvious.

"If the question was 'What is the most efficient tranny?'"

The question was "Geared trannys-more low end torque than hydro "

Just to get a full understanding, my hydrostatic has gears, they don't call it 1st 2nd 3rd etc., but L, M, H, all done with gears.

Your comments are very good. You have contributed some great information on this post. I'm sorry you take my comments as condescending. Rat...

_RaT_ · Sep 8, 2004

I realize it was a apples to grape comparison, that was why the bet was so large and the use of those smiling faces. Perhaps my sense of humor did not come across, Rat...

slowrev · Sep 8, 2004

Soundguy,
You pretty much covered my opoinion of HST trannies. I have known of situations where a couple dollar O ring went bad in the HYDRO which required $300 or higher in labor to get at the O ring to change it. How about the plastic cooling fan thing sucking up sticks and REAL easy to change /forums/images/graemlins/smile.gif Too much aluminum too. They are also a bit difficult to pull/roll start /forums/images/graemlins/smile.gif

With all that being said I am not totally runling out winding up owning a HYDRO someday, but definately not in a rush to get one.

IMHO Tractors should be sturdy and as simple as they can be and still get the job done.

KNotMe · Sep 8, 2004

I bet when engines were first introduced, people using horses also wondered about repairing the stinking stuff. It was much easier to change a shoe or so. But where are they now.

If a technology is 20 years old, it does not mean it will not be as durable as the one it is designed to complement or replace that has been around longer. Only time will tell.

Secondly the cost of repairs bears no relationship to ruggedness or durability. Issues of demand and supply come into play here, well as complexity of design or compromises in manufacturing.

Thirdly, while longevity is important in a design, it is not the only factor, otherwise our machines will be designed to last forever but may not be affordable. You really should pay for what you will use a in a machine or process.

Finally, at least for now, people downplay ease of use. Most people using these CUTs will never put in the thousands of hours that they need to be proficient enough to overcome the inherent more difficult operation of a geared tractor.

KNotMe

Henro · Sep 8, 2004

but I do have some questions regarding the two. At low Rpm's - will a geared synchro shuttled tranny have more torque than a hydro tranny 

After reading this thread twice...(wonder if I am a *********? /forums/images/graemlins/grin.gif )...did we conclude that the low end torque would be the same, all else being equal but the transmission type?

I'm still /forums/images/graemlins/confused.gif about it to be honest.

My gut is telling me the gear transmission would do better at getting the torque to the ground, everything else but the transmission being equal.

Carrying this thought a little further though, isn't a transmission a torque multiplier? If so, could the HST being infinitely variable, actually provide a lower effective gear capability than a mechanical gear tractor, and therefor offer more torque multiplying effect, and by doing so make up for its internal losses and actually put more torque to the rear axles?

Man, the more I think about this the more I feel like a spider spinning a web.../forums/images/graemlins/shocked.gif /forums/images/graemlins/blush.gif

BillyP · Sep 8, 2004

Now I know why you came up with your name. You do ramble a lot /forums/images/graemlins/grin.gif

Steve_Miller · Sep 8, 2004

Let's use the same tractor that is available in a gear and an HST tranny just for equal HP's comparison. As to your first question: No,(this is my theory) with a gear tranny in first gear at let's say 1000 rpm the tractor will probably sit there and spin (I say probably because this will depend on the traction that the tractor can get depending on power to weight ratios of each tractor and the fact that some people will add extra weight for traction where others will not). An HST tranny at the equivalent speed at 1000 rpm's will probably sit there and spin also, as you don't need high rpm's to generate the torque, you need low flow and a certain amount of pressure, which most tractors can provide down to a certain rpm. There is a point where an engine driving a hydraulic pump will not have the torque to pop the pressure relief valve and every combination of engine and pump will be different to some extent. Where the small hydro power loss will show is at high HP loading, whether it be at top speed on a hill or the PTO is being maximized. Heat accounts for the loss in a hydro. Some people will argue that a gear tranny will run as hot or hotter than an HST, yes, this will be the case for many reasons, one of which in a lot of tractors the transmission fluid is also the hydraulic fluid, which is continuously being pumped through the hydraulic pump (generating heat) whether it is being used for a function or not. Any machine that is built to run on hydraulics is built this way for a reason whether its convience or ease of operation or for precision control (there are many other reasons just to mention a few). The loss is a given, but is worth the small sacrifice in power to provide the gains. Most times the loss is overcome by increasing the HP if the loss has to be made up.
 As to your second question, I don't want to be the person that buys your tractor when you go to sell it if your going to using it as a battering ram /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif. Also I suggest you wear your seatbelt and also invest in a neck brace. /forums/images/graemlins/tongue.gif /forums/images/graemlins/tongue.gif 

Steve