Gear or Hydrostatic Transmissions for Compact Utility Tractors?

[CADplans]

I think RAM is the only one offering a manual in a HD truck

After the first time we drove an automatic pickup in the mud at the back of the farm,,,
we NEVER considered taking a shift pickup there again.

The constant, smooth power allowed us to go through places that were not possible with a sift transmission.

 

[California]

After the first time we drove an automatic pickup in the mud at the back of the farm,,,
we NEVER considered taking a shift pickup there again.

The constant, smooth power allowed us to go through places that were not possible with a sift transmission.

Agree 100%! I described the same reasoning for choosing an A/T Subaru (4x4) in this old post. Here's the relevant part:

One tip for anyone considering an Outback for moderately severe offroad use - get the automatic transmission since its torque converter serves the function of a low range. You can apply all the torque you have traction for, at 0 mph. This is important, to start from a standstill in difficult terrain. With a M/T and no low range you would need to rev high and dump the clutch, then still probably stall as you start lurching over big rocks or whatever you stopped for. The A/T allows maneuvering slowly over extremely rough ground without drama.

For example, each harvest season I tow the trailer down into the back of the orchard where Dad used to bury his 3 speed Chevy pickup. Where he used to make big roostertails to get moving up the plowed slope, this Outback and loaded trailer simply climb back out of there without wheelspin.

Also - someone commented on delay while AWD engages. Outback's system is unnoticeable. A better way to describe it is that it never lets the front axle turn faster than the back axle. AWD is there when needed to get rolling or to power through a curve, without any of the squirrely cornering that a 'real' 4x4 exhibits when you let off the throttle. Have you ever seen videos of World Rally Cup racing? Subaru *owns* that class! Nuff said.

But while that choice is important for motor vehicles, I don't think the reasoning is very relevant for tractors where gearing is always available if you need crawl speed.

 

[k0ua]

Gear owners get free cruise control with the hand throttle.

But it is not the same thing. Your throttle controls engine speed. The pedal controls fluid flow. the Cruise control on a Hydro holds the fluid flow at the same rate. It has nothing to do with engine speed which is set by the same hand throttle a gear tractor has.

The advantage a HST tractor has in mowing is the engine speed can be set in its torque band to run the PTO the best and the ground speed can be infinitely varied by the pedal setting if need be. If mowing a nice straight away then use the cruise function so you do not have to press on the pedal all the time. If you need to slow down because of a tough patch of high growth or the ground is so bumpy the ride is uncomfortable, you can do so without slowing down the engine speed .

You cannot do this with a gear tractor. If you encounter a tough patch or rough ride if you back off of the throttle, the available torque at the PTO drops just when you need it most.. No, you have to stop and put the tractor in a lower gear ratio so that your available torque will keep the PTO spinning and the ground speed will be slowed down. This is one of the advantages of the Hydro tractor. And when the going gets easy again just adjust ground speed instantly by pressing on the forward pedal until you are satisfied with it, and if all is clear and you want to "rest you foot" just hit the cruise and it stays there.

The operation of the Hydro tractor becomes fully automatic and you never really think about making ground speed changes, your foot just automatically does that based on the sound the engine makes or the smoothness in the ride, or if you see visual obstacles ahead you need to maneuver around more carefully.

With the gear tractor you must make a conscious decision of what gear to run in per the terrain ahead. The only problem is that the choice of gear any given instant is either too fast or too slow.. This is even worse when we find ourselves caught between gears like 4th and 5th when 4th and 5th not only require one lever to change but actually 2 levers on a typical 8x2 transmission

The more gears you have of course, the chances of finding that right ground speed will happen. 8 gears are better than 6, 12 gears are better than 8, and 16 is better yet. But in most field work, you will not always have the same conditions.

All of these little gains in efficiency in getting the job done faster and with much less operator fatigue. more than compensate for the loss of horsepower through the hydro system. If this were not true, all of the bulldozer manufactures going to hydrostatic systems would not be doing so.

All of us "Hydro fanboys", are not Hydro fanboys because we are too stupid to operate gear tractors, or too lazy or whatever. It is because most of us see an advantage to operating hydro tractors or we would not buy them. One other reason I operate (one of many reasons) is because as I have aged, my knees are not in great shape, and if I operate a gear tractor for 8 hours my left knee does not like it. I can operate my hydro tractor for 8 hours without that pain. Call me what ever, but no pain, is NO pain.

 

[ovrszd]

I agree with most of James' account.

But still, there are places where gear drive is superior. If you do not use your tractor in those places, stick with HST.

There are places where HST is superior. If you do not use your tractor in those places, stick with gears.

 

[oldpilgrim]

But still, there are places where gear drive is superior.

can you specify? I suspect whatever example you give will be subjective and not substantive. Not trying to be argumentative, I just don't think a good example can be found.

 

[ovrszd]

can you specify? I suspect whatever example you give will be subjective and not substantive. Not trying to be argumentative, I just don't think a good example can be found.

I don't take your challenge as offensive. Rather than go into a lengthy debate, I'll say using ground engagement tools. I pull a 12' tandem disc with my Ford. A 14' chisel with my Kubota. Tasks like that are not practical for me if they were HST.

I'm also an oddity. People talk about how well you can control slight movement in critical situations with HST. I disagree. I can control my tractor movements to a MUCH higher degree of accuracy with gear drive. Too much hesitation and drift in HST to suit me. For example, drive down a steep bank and place your front tire on the very edge of a 10' sheer cliff and then back up the hill with your HST.

 

[k0ua]

I don't take your challenge as offensive. Rather than go into a lengthy debate, I'll say using ground engagement tools. I pull a 12' tandem disc with my Ford. A 14' chisel with my Kubota. Tasks like that are not practical for me if they were HST.

I'm also an oddity. People talk about how well you can control slight movement in critical situations with HST. I disagree. I can control my tractor movements to a MUCH higher degree of accuracy with gear drive. Too much hesitation and drift in HST to suit me. For example, drive down a steep bank and place your front tire on the very edge of a 10' sheer cliff and then back up the hill with your HST.

I will take that challenge. Perhaps all HST's are not equal. I would be happy to do it with my Kioti.

 

[ovrszd]

I will take that challenge. Perhaps all HST's are not equal. I would be happy to do it with my Kioti.

You must be talking about the precision of the HST?? Don't imagine want to hitch onto the disc or chisel??

Only way I can accept an HST in steep terrain is if the brakes are located where they can be used in conjunction with the treddle.

 

[k0ua]

You must be talking about the precision of the HST?? Don't imagine want to hitch onto the disc or chisel??

Only way I can accept an HST in steep terrain is if the brakes are located where they can be used in conjunction with the treddle.

I agree, HST offers NO advantage in the plowing department that I can think of, and with more loss in the transmission it would seem to be at a disadvantage. And my brakes of course are on the left where they could be used in conjunction with the forward or reverse pedals (I have the two pedal setup), and I do use them for brake steering at times. As you know I constantly work on hills, some of them so steep they are very uncomfortable to walk on.

 

[ovrszd]

I agree, HST offers NO advantage in the plowing department that I can think of, and with more loss in the transmission it would seem to be at a disadvantage. And my brakes of course are on the left where they could be used in conjunction with the forward or reverse pedals (I have the two pedal setup), and I do use them for brake steering at times. As you know I constantly work on hills, some of them so steep they are very uncomfortable to walk on.

Yep. Never could figure out why any brand would design an HST tractor that you can't use the brakes in conjunction with the HST pedals. Now there will be posters talking about how they NEVER use their brakes and can't figure out why anyone would want to. They obviously have not been on our hills......