Not to nit-pic, but the questions sound more appropriate for a marketing study, than a mechanical engineering study....

can you tell us more about your project, is the intent to produce a specification, to design a prototype, or is it a research paper? Tell us what you know so far, and if at all possible, please elaborate on your own background - specifically in terms of academics... what sub-branch of mechanical engineering are you focusing on in your studies?... etc...

This will allow us to formulate responses in a manner that will facilitate compilation of data for your project...

For the most part, people want a HST that will be more reliable for longer with a cheaper price tag. You deliver that and all will be happy!

The point of my study is to find out what are the customer demands on HSTs to translate them into technical specifications in the first step and then generate new product concepts which have either technological or econmoical adavantages against the existing ones.
Therefore if you could tell me directly how high the working pressure, displacement and design of pump and motor should be then i would be happy and it will safe me a lot of work.
But also i wanna use the these responses to may be find some new ideas to problem one encounters when using the machine and nobody thought about solving it yet.
To my background I am studying at a university in Germany, close to Stuttgart. And I am specialising in Design & Development. As I told you before this my final project which is seperating me from graduating.

May be you wanna know, why I am asking on a American homepage for help and not a German:

1) From expierence I know Americans are much more willing to help then Germans.
2) The US are the biggest market for this kind of tractors.

From the top,
price is important, but I like something that isnt going to break if I use it for things it might not have been intended.
All my tractors are gear tranny, hydro in the same price range (new and second hand) are not nearly as good. Nowhere near the power, they whine, they break, you cant abuse them. You have to spend alot fo money to get a hydro that will begin to do these things.

You need to decide if you are wanting info on low price hydros, or high price hydros, a world of difference between them.
Low price hydros tend to whine, and you cant use them for much more than mowing. A low price hydro that was tough and robust and could be abused would be good.
High price hydros are good, but you always want more power transfer from them, they waste about 10% of the engines HP. Lower that to 3-5% and youve done a good job.

If you want to make something real cool, how about a hydro tranny, but with some gears that you can select for pulling, so a hydro tranny with gear override.

Hydros are a time saver. For mowing, the ability to go foward and backwards without clutching or shifting makes an amazing difference. A hydro with a loader or any kind of hydraulically operated implement is the cats meow. I'm on my 4th machine with hydro drives, and the only other kind of transmission I would even consider is a "power-reverser", which is kind of the best of both gear and hydro-driven drives.

Good luck with your studies.

Cheers

JDFANATIC

I've had gear driven tractors exclusively for nearly 40 years, not knowing what I was missing - Maybe that was a good thing, as in their infancy, HST's weren't always highly reliable and wouldn't stand up to hard use. Those shortcomings are pretty much a thing of the past

You find HST's on 'real' tractors these days and most all of the modern CUT's have them now and you seldom ever hear of any failures. A tractor with a 3 point hitch and a PTO was designed to WORK and if it's HST couldn't cut the mustard, we would all have heard about it by now

I bought a heavy duty Kubota diesel in part because of it's excelent HST and I love it - You couldn't GIVE ME a geardrive tractor ever again. Reliability is important of course but the key is ease of use . . . . an HST equipped tractor can mow circles around a gear driven model, especially on lawns which have many trees, flowerbeds and other objects to maneuver around. It's important to have a user friendly 'actuator' for the transmission, so you can instantly go from forward to reverse and change speeds at will. For me, this is a rocker foot pedal, like my Kubota employs. Instantly variable ground speed while the mower deck runs at full speed just can't be beat. While it might be handy once in a while, you don't really need a dual range transmission if your HST can take the full engine HP at slow speeds and not overheat. My Kubota HST is a single speed and even when using it to pull posts, trees and stumps, it does fine and I've never once wished it was a dual range

A good HST compared to a gear driven trans is like comparing a 1930 Model A with a non-synchromesh gear transmission to a 2006 Lexus with an automatic transmission - That is to say, there really is no comparison at all. Drive a modern tractor with an HST and very likely you'll never, ever even look at a gear drive tractor again

Don

What is most important to you when buying a garden tractor (e.g. price, performance, ease of use, other)?

Toughness. Easy to maintain.

Why did you choose a hydrostatic transmission (HST) instead of a mechanical transmission or the other way round?

Time saver when mowing.

What do you like or dislike about current HST?

Like current unit. Past HST unit was slow going up hills.

What are your demands on future HST?

It should pull a load with the solid feel of a good gear drive and be infinitely adjustable in speed like a HST drive.

So let me wrap these comments up:
The reliablity and robstness is a big point which you usally only find in more expensive HSTs - so theirs a trade off between price and reliabilty / quality overall.
Second, a hydro is defintely easier in use and saves time as well.
Actually a hydro without any range/gear would be best but then using it for pulling and so on is not possible all the times. So second trade off is between power/performance and ease of use.

did i get it right? please correct me!

But what about other issues...like top speed, maintenance, noise level, vibrations? Does your tractor ever leave tracks on turf from spinning whees?

Lastly how about goodies like cruise/speed control, different operation modes (eco/sport) or others?
i for example started to work on a hydrosystem which you can shift on the fly...during the hydro is virtually idiling you can make a gear shift.

thanks for your comments

Marco

"did i get it right? please correct me!"
Yep, looks good to me. Something I would add, gear is generally regarded as better for high strain applications, such as plowing or towing loads.

Top speed, more is better really, but having the low speeds is also important. Nise level and vibrations, the less the better.

Yes, my tractor leaves tracks, but only when I'm doing something I shouldnt (towing too heavy loads, going out in the mud....)

"Lastly how about goodies like cruise/speed control, different operation modes (eco/sport) or others? "
IMO, its a tractor, those just add unnecessary expense, and its more to go wrong.

something came to mind...

so if we compare the price and the reliability:
if i am a first time buyer...how do i know about the reliabilty (neglecting my buddies gave me some advise)? how will i choose by price only? performance?

I think any big name brand will be reliable when used as the manufacturer intended . . . . if it doesn't offer a 3 point hitch, probably they didn't intend it for plowing or serious pulling, like a grader blade, etc. If it DID come with a 3 point (or one is offered as an option) then it's HST is probably a serious unit which can handle whatever abuse you might care to dish out. If it has a diesel engine on one end and a 3 point hitch on the other, you needn't worry about the HST for doing anything in my opinion

Cruise control on an HST is usually just a simple mechanical contraption to hold the HST pedal where you want it and releases when you touch the pedal or the brake, at least that's how it works on my Kubota

Gound speed? Mine's 0 to 9.3 MPH - Faster than most gear drive tractors offer

Don

My 34 yr old MF's all have duel range hydrostatic drive, foot pedal controlled, with cruise. I will NOT buy any brand tractor unless it's so equiped. I really wish you luck making something better, might be a rough road to hoe though, at 34 years old mine still work great with regular filter and fluid changes, they haven't been babied either, one of them I use for a push tractor at my auto shop.

ok i agree with all you guys said, but why are the premium brands like cnh and jd loosing market share against usally cheaper asian manufactures like mahindra, kioti...?

Upfront price is the prime consideration (only consideration for some) for many buyers - The fact that they need a new machine every 6 or 8 years isn't even considered. Others prefer to make a 'lifetime purchase' and think paying 50% more is a really good deal

It all depends on your perspectives

Don

After 2 full seasons of mowing and mulching leaves my Deere L-110 with Tuff-Torq K-46 has 25 hours on it. Given my overall use rate I would be shocked if my L-110 wasn't working as new 18 more years from now, when it should have all of 250 hours on it. As I understand it these machines have a minimum design life of 500 hours. 18 years from now I will be 77 and probably thinking about hiring someone to do my yard work. Really the 17.5 hp Kohler Command on it is a 1000-hour engine atop what is supposed to be a 500-hour tractor/transmission I guess.

Talk to me about the how long the more expensive Deeres are supposed to last, hour wise.

The Deere as mulcher saved me a heck of a lot of work on my leaf cleanup this fall, and my lawn currently looks just like the bagged and carted lawns on the street, as the mulch works its way into the soil. Given that, I don't see the point in the raker attachments.

David

It's not likely that your engine or transmission will cause the untimely death of your L110. It is more likely to come from one of the weak links.
{{gwi:355100}}
Pick a letter.

Contact Ingersol-Rand and ask for the specs on the old Case garden tractor hydraulic transmission. That was the best and strongest transmission ever built. It was used on all their tractors from the 8hp up to the 20-plus hp units. It has a hydraulic retarder/brake as well as a hill-holder type device built in. I have had two of these, a 10hp and 16hp with loader and never had any problems with them. Power,reliability with no problems,minimum of maintenance.

wheely boy.... that weak link is only weak, if one plans on tearing tree stumps out of the ground, by running into them with their deck....

That part ain't gonna wear out.... because that link sees "no stress"... nothing pulls on it... nothing bends it... it's 1/2" steel... 1/2" dia. cheap steel rod has a tensile strength of 3000 lbs..... ummmm one would assume that ought to be OK for the L110 :-)

My L120 has 250 hours on it - 2 years.... still going strong, and I use and abuse it... we'll see where I am in 5 years....

The belt pushes on it and with varying amounts of force, depending on what the deck is cutting - The rod is probably strong enough, but the stamped piece of tin it ties into is weak. It's nothing at all like the mounting arrangement on a quality mower. Eventually, you're going to need to weld up something better . . . . .

Don

Thanks so far for your frequent replies and sharing your opinions with me and some specific advises.

Are there some more opinions from other members?

Cheers

Marco

What university are you studying at? I will be in Stuttgart, Hanover, and Bad Essen in December and travel there quite frequently for business.

i am studying in esslingen, which is a suburb of stuttgart.
i would be pleased to meet you!

Wheely Boy,

The more serious threat of the front wheel falling off , or the machine catching fire has eclipsed the deck hanger engineering marvel.

No back to our regular broadcast

Duc

Posted by babyjack wisconsin (My Page) on Fri, Nov 24, 06 at 10:40

Contact Ingersol-Rand and ask for the specs on the old Case garden tractor hydraulic transmission. That was the best and strongest transmission ever built. It was used on all their tractors from the 8hp up to the 20-plus hp units. It has a hydraulic retarder/brake as well as a hill-holder type device built in. I have had two of these, a 10hp and 16hp with loader and never had any problems with them. Power,reliability with no problems,minimum of maintenance.
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Let me clarify a few things with regard to the above post.

First off, the tractor mentioned was initially invented by the owners of Colt in the sixties and they produced garden tractors for a couple of years prior to being bought by J.I. Case who redesigned the line and expanded it. In the early 80's, Jack Ingersoll of the infamous Ingersoll-Rand family, bought the line from Case and then ran the company into the ground by selling it to a German consortium. Ingersoll-Rand never had anything to do with this tractor but they did buy up the Melroe Bobcat. Currently, the Ingersoll line of tractors is being revived by a new owner.

Aside from the above history, I agree that the the two-speed transaxle used by Colt/Case/Ingersoll is one tough puppy and except for a minor issue with spider cage bolts loosening in certain years, these units have stood the test of time for nearly forty years.

However, the discussion is about hydrostatic drives, not hydraulic drives. Ingersoll still uses hydraulic drives in their tractors today but on certain lower end models, they did employ hydrostatic pumps.

Marco, There is a British designed approach to this problem you might want to check out. See Torotrak.com. Derivation of a automotive CVT style design. Could inspire some design options for you.

:Gound speed? Mine's 0 to 9.3 MPH - Faster than most gear drive tractors offer"

My Cub 1864 (which happens to have the Heavy-Duty Sunstrand Hydro) has a top speed of 8-9 mph.

That's plenty fast. In fact, that's hauling a$$ on a garden tractor :)

-Larry

mrtractor:

http://www.torotrak.com/IVT/works/variator.htm
That looks like a pretty cool setup. But... ISH! It looks complex and fragile.

Do you know anything about the lower-end Dixon ZTRs? They have a similar system of conical clutches which seem to be just prone to breaking. Usually the clutches burn out or the input or output shaft breaks. I suppose it depends on the the use and abuse, but usually ZTR purchasers want something with a quick reaction and reliability.

Hydrostatic systems as all things, are a compromise. It depends on what is wanted/needed. If you can get slave labor in China to build it for you, that always helps the selling point.

I would think that an ideal garden tractor should be able to go about 7mph (who needs more), have a well-designed fully-jeweled system (all ball or roller bearings) which doesn't rob more that 5-10 hp under decent load, is fully serviceable when it comes to fluid and filter, and provides 1000-2000 psi for power steering and auxilary attachments. Boy is that going to cost someone money though!

For the normal home-owner, a CVT system seems to be ideal. Look at all those MTD products out there which incorporate the variable speed system! Now if only the rest of their product was engineered a little stronger and servicable. Oh.... a consumer should be able to get parts for their purchase once it breaks down..... hmmm... (MTD).

So who makes the cheap, whiney hydrostatics? Peerless? Tuff Torq's T40?

AYP uses the K46 (according to their manuals) in every Husqvarna mower from 15-26HP.

JD uses the K46 in it's bigger Home Depot tractors while they have that lighter T40 in in the smaller one.

JD uses the Kanzaki K58 in most of the 3 series. The X304 has just 17 HP. It is $3.5K though.

Kubota uses Hydro-Gear (I can't recall which) in the T series. I've heard some say they are bullet-proof.

What does Cub use in the 1000 series? People here snipe at their hydro the most.

Where does the "good" hydro start? One that won't whine and will give decent performance with lighter duty? I thought it might start at the K46. Am I correct?

I wouldn't call them "cheap and whiney" but the Tuff Torq K46 and the Hydro-Gear 0510 (used in Craftsman and earlier Husqvarna LTs) are similar and are both low end. Here are their specs:

Tuff Torq Hydros
Hydro-Gear Hydros

-Deerslayer

Hello Marco,

I hope your project is coming along well. I have had two Wheel Horse tractors with Sundstrand transaxels. The first was 14 years old when I got it. My Current tractor is a Wheel Horse Charger made in 1969.

Both are 100% reliable. These tractors use a single forward/reverse lever control located just to the right of the steering wheel. No "cruise control" is required as the lever will stay where you put it.

The tractor can be stopped by returning the lever to the middle position. There is a foot pedal that can do this. I find this very handy. The foot pedal on these tractors is on the left, Familar to me since I grew up driving a WH suburban manual with the combined clutch/brake on the left. But probably this should be on the right for optimal ergonomics.

I agree with others who say that hydro is the way to go 100%. When mowing not only is it good when you need to back up or manuver, it is also very good for when you hit a thick patch of grass or have to slow down to negotiate a slope.

I also use a dozer balde/snow plow and having the ability to go from forward to reverse to forward is really nice.

The only real disadvantages I am aware of is the fact that hydros use more gas, and cost more.

So, if you can improve the efficiency that would be good. Or maybe reduce complexity or weight.

The other thing I like with the Sundstrand is they have ports for other hydraulic attachements. I wish the were brought out to some sort of common fitting (or quick fit) so that adding accessories would be a matter of modular connections versus having to remove plugs, add shimes, etc to use this feature.

Like Larry I have a Cub Cadet 1864, mine is a 1997. I had asked on a different forum about the whine I was hearing from the hydro, it was a bit louder than several other Cub hydros we've owned. I was assured there, and since from a dealer, that this Sundstrand hydro is very strong and they all whine loudly from the day they are new.

I only mention this so people don't associate "whiney" with "cheap".

Posted by wheelhorse_of_course (My Page) on Fri, Jan 5, 07 at 1:54

The other thing I like with the Sundstrand is they have ports for other hydraulic attachements. I wish the were brought out to some sort of common fitting (or quick fit) so that adding accessories would be a matter of modular connections versus having to remove plugs, add shimes, etc to use this feature.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
*********************************************************

Wheelhorse,
If the Sunstrand pump is a single hydrostatic pump and not a dual pump, then you cannot power any attachments of any kind off of it.

A hydrostatic pump only pumps oil when the swash plate is tilted from its axis. It is this tilting that causes the direction of oil flow and the volume of oil flow to change. Changing the direction of oil flow is what gives you the seamless forward and reverse of your tractor. The more the operator tilts the swashplate, the greater the GPM from this pump and that translates into greater ground speed.

If the tractor manufacturer wanted to offer implements that were hydraulically driven, then he would have to select a hydrostatic pump that would acommodate a piggy-backed hydraulic pump with a separate open-centre control valve/s with quick-couplers.

That's one of the beauties found in the Ingersoll line of tractors. They use a single hydraulic pump to power almost everything.

Castoff,

while I have note used any of the hydraulic accessories, I am 89% sure they use the exact same pump. It was just that the hydraulic lift was an "option".

So I guess we agree that this is a very nice feature Marco should consider.

IF....... they use the same pump, then it is not a simple hydrostatic pump.

As I said previously, a simple hydro pump cannot do what you suggest.

Picture this. You have a hydraulic rototiller attachment or a hydraulic finishing mower or snowblower that needs eight gallons per minute constantly to operate at peak efficiency.

If the tractor is sitting still, the hydro pump is not pumping a single ounce of oil. If you move the tractor forward, then the amount of oil being pumped is relevant to the speed you select. If the hydro pump is capable of 10 GPM at 3600 RPM and you only ask for 50% of that output because you want the tractor to travel at half speed, then the GPM produced will theoretically be 5 GPM.

And that GPM is contingent upon you not slowing down because the second you do, the GPM will drop accordingly.

Reversing the tractor would be out of the question because if the flow of oil is reversed, so is the direction of the motor powering the snowblower, finishing mower and any other attachment.

I am not saying that you are wrong about your Wheelhorse. All I am saying is that they must have developed a special pump for it in order for it to perform tasks other than making the tractor move forward and backward.

If that's true, then I hope you never have a problem with your hydro because proprietary pumps are usually super expensive to buy from the manufacturer.

If it was my machine, I would be changing the oil on an annual basis to protect this pump.

Your turn.

Agreed. And I do believe the reason I remember it being complicated to add implements because there were shims and springs that were part of a bypass circuit when the implements are not used.

I need to get off my butt and go out to the garage and get the manuals.

Anyway, they've used the same hydro pump/transaxle combo in the wheelhorse's for several decades so used parts are readily available. But it is a very integral assembly with the pump, hydro motor and transaxle all tied together. The link what it looks like.

It most certainly is not a pump you could replace with something from Northern!

I believe Wheel Horse claimed to be the first hydro L/G tractor, but I could be wrong. I do know they first used these in the 60's. There were a few models that used eaton instead of sundstrand, but the vast majority used the same sundstrand setup.

You are right though, preventative maintenance is the way to go. Replace fluid and filter every season or every 100 hours (at least once I get the hour meter installed).

cheers

Here is a link that might be useful: Hydro transaxle

Thanks for the link.

What a beautiful piece of engineering. Makes the crap they churn out today pale in comparison.

All cast iron except for the finned aluminum pump.

I think you would appreciate the Case/Ingersoll transaxle that has been in use since 1964 and is still being used today. I looked to see if Joe had one listed on eBay to show you but no luck.

Am I right in concluding that the WheelHorse transaxle was driven by a belt off the motor? If so, I would have expected to see the pulley on the shaft protruding from the end of the pump.

Yes, when you see one pictured, let me look at the Case/Ingersoll.

You are correct, there is a pulley, with built in fan, that mounts on the end. The seller probably is selling it seperately.

The belt drive has a idler/clutch so the pump can be disengaged during starting. It also activates the parking brake.

There's a reason why so many of those old tractors survived! I figure every single peice on my 1969 horse was made in the USA.

Cheers

Here is a link that might be useful: Fan/pulley

Castoff,

You were right. There *are* two pumps, but they are integral to the same pump subassembly. There is a low pressure make up charge pump that refills any fluid in the main circuit that is lost (e.g. through the relief valves, etc). This feeds the low pressure side, of course. This charge pump feeds from the reservoir into the main loop (pump/motor). This charge pump is what is used to drive accessories.

I HAVE A 1996 CRAFTSMAN 25 HP WITH THE HYDROSTAIC TRANS. THIS YEAR THE TRANS WAS WORKING FINE, I STOPPED, WENT BACK AND FORTH FROM DRIVE TO REVERSE 2 OR 3 TIMES TO LINE THE TRACTOR UP WITH MY SHED AND THE TRANS STOPPED WORKING! THERE ARE NO LEAKS, THE DRIVE BELT WAS NEW LAST YEAR & THE BRAKE DISC IS SPINNING WHEN THE BRAKE IS NOT APPLIED. IT SOUNDS AS IF IT IS IN THE BYPASS MODE WHEN YOU PLACE IT IN DRIVE OR REVERSE. I CAN PUSH THE TRACTOR WITHOUT PLACING IT IN BYPASS MODE. WITH THE REAR WHEELS OFF THE GROUND AND IN GEAR, THE WHEELS BARELY SPIN.I DIDN'T HEAR ANY UNUSUAL NOISES WHEN THE TRANS STOPPED WORKING. THE TRACTOR HAS ALMOST 500 HRS ON IT. I DON'T KNOW IF THE PUMP COULD HAVE DIED OR IS THERE A PRESSURE VALVE STUCK INSIDE THE UNIT?