Does HST Transmission Rob Horsepower??

[4570Man]

In theory yes but a when you’re comparing a compact tractor the HST one will almost always be done faster. Even in a test that’s a direct comparison of driveline power like pulling a wagon up a hill the HST could end up winning. A compact gear tractor never has enough gears to get the right one and you have to compromise on to slow. The HST could go exactly the speed you want.

 

[Hay Dude]

The convenience of not having to feather a clutch or keep one hand on a shifter when doing a delicate operation or where speed could vary widely & rapidly, HST is nice.

 

[Emainiac]

I owned a gear shift for 15 years and never thought twice about having to use the clutch so frequently. I would grade my driveway, plow snow and haul logs, so it really was not an issue at all. Then the time came for me to get a larger tractor last year and since all the dealer had was HST, I figured I'd test drive one since they are so popular. I spent an hour on their lot and didn't really have a chance to put it to work. But I was anxious for a new ride so I bought it and had it delivered a day later.

The big day came and I was planning to spend the weekend spreading about 15 yards of loam. Inside of the first hour, I knew I had made a mistake. I would approach the pile and the machine would bog down and then finally get the balls to lift a load. It almost felt like a 1-2 second delay from what I knew. No where near as responsive as my gear was. Needless to say, I was disappointed and called the dealer and he asked me to stop by so he could "teach" me how to drive an HST, because they are clearly different than gear. Even after spending an hour learning that you do not press down on the pedal when approaching a pile, it just did not feel right to me.

Since they did not have a gear version on the lot, I drove to another dealer and hopped on a shuttle shift version of my tractor and knew in 10 seconds flat that was what I wanted. It fit like a glove. So I returned my HST with 3 hours on it and waited another 3 weeks for a shuttle version to come from the factory. Best decision I ever made.

I'll agree with earlier posts that HST is more popular because the majority of suburban tractor owners (who make up a lot of the tractors sold) are clueless how to use a clutch. There is no doubt that HST's have their place for certain types of work, as do shuttle/gear. It is a personal preference and I cannot think of a single occasion where my shuttle did not do everything I have asked it to do, even delicate task that require me to move only an inch.

While you may not spend much time using the clutch with an HST, you make up for it reaching for the cruise control.

 

[4570Man]

I owned a gear shift for 15 years and never thought twice about having to use the clutch so frequently. I would grade my driveway, plow snow and haul logs, so it really was not an issue at all. Then the time came for me to get a larger tractor last year and since all the dealer had was HST, I figured I'd test drive one since they are so popular. I spent an hour on their lot and didn't really have a chance to put it to work. But I was anxious for a new ride so I bought it and had it delivered a day later.

The big day came and I was planning to spend the weekend spreading about 15 yards of loam. Inside of the first hour, I knew I had made a mistake. I would approach the pile and the machine would bog down and then finally get the balls to lift a load. It almost felt like a 1-2 second delay from what I knew. No where near as responsive as my gear was. Needless to say, I was disappointed and called the dealer and he asked me to stop by so he could "teach" me how to drive an HST, because they are clearly different than gear. Even after spending an hour learning that you do not press down on the pedal when approaching a pile, it just did not feel right to me.

Since they did not have a gear version on the lot, I drove to another dealer and hopped on a shuttle shift version of my tractor and knew in 10 seconds flat that was what I wanted. It fit like a glove. So I returned my HST with 3 hours on it and waited another 3 weeks for a shuttle version to come from the factory. Best decision I ever made.

I'll agree with earlier posts that HST is more popular because the majority of suburban tractor owners (who make up a lot of the tractors sold) are clueless how to use a clutch. There is no doubt that HST's have their place for certain types of work, as do shuttle/gear. It is a personal preference and I cannot think of a single occasion where my shuttle did not do everything I have asked it to do, even delicate task that require me to move only an inch.

While you may not spend much time using the clutch with an HST, you make up for it reaching for the cruise control.

I wouldn’t be that apposed to a good shuttle shift transmission and not at all apposed to a torque converter transmission like a lot of construction equipment has. But those are a totally different beast than a dry clutch gear trans.

 

[Cougsfan]

Wow, this thread is really getting a little tribal! I grow weary of reading "if anyone who doesn't agree with my particular choice of transmission, they are obviously mistaken." Having owned and/or operated HST, geared tractor with dry clutch or shuttle for many years, I can understand how someone could prefer one over the others, either way. None can claim absolute superiority for all conditions, and each have advantages in certain conditions. And if one has any ability at all to adapt, one could easily live with any of them under most any condition.

 

[buck12]

Wow, this thread is really getting a little tribal! I grow weary of reading "if anyone who doesn't agree with my particular choice of transmission, they are obviously mistaken." Having owned and/or operated HST, geared tractor with dry clutch or shuttle for many years, I can understand how someone could prefer one over the others, either way. None can claim absolute superiority for all conditions, and each have advantages in certain conditions. And if one has any ability at all to adapt, one could easily live with any of them under most any condition.

Well stated. For my uses after owning a gear drive tractor for 12 years and now a HST for almost two years, HST is better for me. Both will accomplish the work I need to do on my property but the HST is faster and easier to operate.

There is no right or wrong, just what works best for the most of the users uses.

 

[5030]

....and ALL transmissions have parasitic loss of power between the flywheel and the final drive. Obviously, HST's have more than standard gears. All distills down to what you prefer.

 

[5030]

I'll agree with earlier posts that HST is more popular because the majority of suburban tractor owners (who make up a lot of the tractors sold) are clueless how to use a clutch. There is no doubt that HST's have their place for certain types of work, as do shuttle/gear. It is a personal preference and I cannot think of a single occasion where my shuttle did not do everything I have asked it to do, even delicate task that require me to move only an inch.

Why I prefer my hydraulic shuttles. One, there is no dry clutch to wear out and two it's extremely manageable especially when moving in small increments. The 'clutch' is a wet multi plate wet pack so there is basically no wear. In 6000 hours, I've never adjusted the freeplay on the 'clutch' pedal and that is 99% loader work.

 

[CoyPatton]

It amazes me how many commenters have dropped a portion of the question (seemingly to support their position). The ‘from the PTO’ has disappeared from their responses.
Perhaps it was poor word choice, but at the same time it is out many will state the hp issue from gear drive to HST drive.
Frankly the brand makes little difference in this discussion. Stay in the same brand your choice green, blue, red, orange or whatever. Select a model that comes in both a gear and HST drive, and you will consistently see that in the HST drive less hp gets to the PTO. This makes the tradition engine hp description much less useful. And face it 99% of tractor buyers ate doing so for PTO project involvement, be it mowing (finish or rough), tilling, broadcasting material or any number of activities. So now with the movement so strongly toward HST, PTO hp becomes more important than engine hp.
The simple fact is that with an HST tractor, more hp will be consumed prior to reaching the PTO than on a gear driven tractor. Is this a bad thing? Probably not! But for PTO operations, the buyer needs to aware!

 

[Cougsfan]

To continue splitting hairs that don't make much difference; the PTO drive does not go through the HST, so there is no power to be lost to the PTO because of a HST. So if the tractor is stationary the PTO HP on a HST or shuttle will be identical. If the tractor is being driven, engine hp is being used to both power the PTO and to move the tractor. The HST does use more of the engine hp to drive the tractor, making less available to the PTO. But in a situation such as mowing heavy brush where PTO hp is an important consideration, the PTO is usually consuming the bulk of the engine HP while moving the tractor isn't using much power at all, so the real world difference is quite negligible. However in the extremely rare instances you are mowing thick brush while going up a steep hill at maximum speed in high range, you would likely see a noticeable difference.

 

[4570Man]

To continue splitting hairs that don't make much difference; the PTO drive does not go through the HST, so there is no power to be lost to the PTO because of a HST. So if the tractor is stationary the PTO HP on a HST or shuttle will be identical. If the tractor is being driven, engine hp is being used to both power the PTO and to move the tractor. The HST does use more of the engine hp to drive the tractor, making less available to the PTO. But in a situation such as mowing heavy brush where PTO hp is an important consideration, the PTO is usually consuming the bulk of the engine HP while moving the tractor isn't using much power at all, so the real world difference is quite negligible. However in the extremely rare instances you are mowing thick brush while going up a steep hill at maximum speed in high range, you would likely see a noticeable difference.

Exactly. In the more reasonable comparison of mowing heavy grass on mostly flat ground there would be very little difference.

 

[Cougsfan]

One more note; If you are indeed concerned that a HST might leave you short of PTO horsepower, you should really consider buying a larger tractor, regardless of the transmission type you prefer.

 

[ericm979]

I'm certainly not in the anti HST camp as that's what works for me. But I think that HSTs do lose a little power vs the same model gear trans even when stationary and running a PTO implement like a chipper. I base that off of manufacturer's specs where the PTO HP is usually a little lower for the HST trans.

Remember that an HST is basically a pump and a motor. One or both can be variable displacement. I think that in most modern CUTs it's the motor that is variable and the pump is fixed displacement. Which means that even when stationary and the range trans is in neutral, the HST pump is pumping fluid. Even though the motor side is not doing any work, that fluid has to go somewhere. The engineers most likely make it go somewhere with a low resistance to flow but it's not zero. Thus some power, like ~1hp on a 40hp machine, is being used by the HST even when stationary.

 

[dieselscout80]

While it is just one Hydro tractor note the Max Pull numbers for all of these IH 544 variants.

I would not have guess which on had the highest Max Pull rating of 6,579 lbs.

TractorData.com Farmall 544 tractor tests information

www.tractordata.com

What does it prove not much.

What IH said was that the tractors with Hydros excelled at PTO work due to no gear splits to limit the operation, so the perfect speed could be obtained.

I know that when mowing or baling sometime you need to slowdown, but the next lower gear is way to slow.

 

[4570Man]

While it is just one Hydro tractor note the Max Pull numbers for all of these IH 544 variants.

I would not have guess which on had the highest Max Pull rating of 6,579 lbs.

TractorData.com Farmall 544 tractor tests information

www.tractordata.com

What does it prove not much.

What IH said was that the tractors with Hydros excelled at PTO work due to no gear splits to limit the operation, so the perfect speed could be obtained.

I know that when mowing or baling sometime you need to slowdown, but the next lower gear is way to slow.

I’ve been saying that for a long time about a HST tractor. If you had a bunch of gears you wouldn’t have that problem but a compact tractor practically never does.

 

[ptsg]

I’ve been saying that for a long time about a HST tractor. If you had a bunch of gears you wouldn’t have that problem but a compact tractor practically never does.

Most tractors these days offer at least 12 speeds forward and 12 reverse, you're saying that in 12 gears you can't find one that suits the job? That's impressive.

On my end, I can have at least three different gears all the time that I could use for the same job, and if I'm doing PTO work, I can still "split" those gears by using 540E.

Even a 9x3 transmission will still have plenty of gears.

 

[dieselscout80]

Sometimes it is not the lack of gears, but rather the gear splits.

If you need to use/go one gear below a range or use/go to one gear above a range you have to completely stop.

I look at this when I am look for a newer tractor.

I like to mow my pastures at 3.5 MPH and having the ability to down shift if the grass is thick its important to me as I do that shift often in places.

I think if I had a tractor with range of four synchronized gears with nice even 1 MPH splits starting say 1.5 MPH (e.g., 2.5, 3.5 & 4.5 MPH), then I may never have to switch ranges for most work on our property.

I guess what I am saying its the correct gear combinations that is important. With some tractors I have looked at the 2.5 MPH and 3.5 MPH gears are in different ranges.

That said I make do with a gear drive tractor with 8 unsynchronized gears.

All the upgrades to tractors just make them nicer to operate and to each his own.

What tractor/transmission you chose is simply your choice and it not right or wrong it just yours and I hope you enjoy operating it.

 

[Hay Dude]

Most tractors these days offer at least 12 speeds forward and 12 reverse, you're saying that in 12 gears you can't find one that suits the job? That's impressive.

On my end, I can have at least three different gears all the time that I could use for the same job, and if I'm doing PTO work, I can still "split" those gears by using 540E.

Even a 9x3 transmission will still have plenty of gears.

I cant get the correct gear sometimes even with 16 speeds!
Especially with hay work.
Sometimes the difference between 5 high and 6 high is raking too slow or too fast.
The newer version of my tractor has 24 speeds (3x8). My older version is a 16 speed (2x8). I find myself looking for those “in between” gears sometimes.

 

[Hay Dude]

Wow, this thread is really getting a little tribal! I grow weary of reading "if anyone who doesn't agree with my particular choice of transmission, they are obviously mistaken." Having owned and/or operated HST, geared tractor with dry clutch or shuttle for many years, I can understand how someone could prefer one over the others, either way. None can claim absolute superiority for all conditions, and each have advantages in certain conditions. And if one has any ability at all to adapt, one could easily live with any of them under most any condition.

Good point. I also have observed that although this is “Tractor by Net” it is mostly “[small, under 75HP] Tractor by Net”. Hydrostatic is going to be disproportionately more popular HERE because larger tractors are unavailable with hydro.
The last 20 years in bigger tractors has seen the emergence of IVT/CVT transmissions. Drives like a finger-touch hydro.....
I thought it couldn’t get better when the push button powersfhift transmissions came out. The IVT/CVT is even better. Extremely nice to operate.

 

[aczlan]

To continue splitting hairs that don't make much difference; the PTO drive does not go through the HST, so there is no power to be lost to the PTO because of a HST. So if the tractor is stationary the PTO HP on a HST or shuttle will be identical. If the tractor is being driven, engine hp is being used to both power the PTO and to move the tractor. The HST does use more of the engine hp to drive the tractor, making less available to the PTO. But in a situation such as mowing heavy brush where PTO hp is an important consideration, the PTO is usually consuming the bulk of the engine HP while moving the tractor isn't using much power at all, so the real world difference is quite negligible. However in the extremely rare instances you are mowing thick brush while going up a steep hill at maximum speed in high range, you would likely see a noticeable difference.

The HST still has the charge pump running even if you aren't moving, so that constant load is the difference between the PTO HP of a HST and a gear tractor.

That said, for brush hogging I would much prefer a HST over a geared tractor and slightly over a shuttle shift with torque converter such as Kubota's GST. It is much more convenient to be able to bump forward or backwards a couple inches with just your foot and not have to change a lever or move otherwise.

So, for anything besides heavy dirt work (such as plowing/disking a field) I would go with HST or possibly a GST transmission

Aaron Z