HST ? improved over the years

[lawn_king]

30 years of working tractors here. International gear & kubota hydros. Both have been great! Im about to jump up to a kubota hst + transmission. Its just a marvel of hydro engineering, with the stall gaurd, auto throttle & adjustable hst responce, its like driving the 6 speed in my new pick up. Hydrostats (imho) started out good and just keep getting better!

 

[Yankee Clipper]

This is not intended to be a sales pitch but a response from a tech person.

I can speak for the Kubota Grand L 40 hydro. The new hydros are electronically controlled and they have load sensing, a hydraulic gear splitter and auto throttle. You also can set the response so you get a modulated (smooth) start and stop or immediate response, like the old systems. They are easy to operate, smooth as glass which makes the experience better and you are more productive because the computer is working for you.

The smooth operation found between a Kubota Grand L 30 series and 40 series is considerable. The 30 series is/was a very good system but the 40 series is much nicer in all respects. The cost increase is not that much in the scheme of things and yes, the reliability of the electronics is there. (No one worries about reliable solid state ignition on their cars anymore, do they? The same companies build these electronics.)

The future is here now and you will really appreciate the difference electronics make.

Check it out at your dealer.

 

[JC-jetro]

Hi all,
I understand all the advantages of the Hydro but sometimes shear simplicity is the key. A simple hammer always work as long as you can hit the nail and just about nothing to maintain. It just appears to me the condition of the hyd fluid, cleanness, filtration of the sediment and stuff is of utmost importance for proper operation. It looks to me when time is of essence and every second counts one can not discount HST. Hydraulic driven motor is a marvel of engineering indeed. My question is what kind of service can you get or expect from HST transmission if your total use of tractor maybe in the neighbor hood of 30 hrs a year with long storage time without activity? As the adage goes "use it or loose it". looks to me HST has to be used constantly to have a better life expectancy. I hate the darn thing to "dry rut" in storage.

No flow/no pressure= no go and that bothers me. You can see 60 yr old tractor that still keeps on going.. may not be going fast .. but keeps on going.

Just my 2 cent. I appreciate ya'lls opinion.

JC,

 

[PA hayseed]

Things I would use the CUT for:

Loader work (gravel, dirt, mulch)
backhoe
Roto tilling,
skidding logs
light grading
setting landscaping
shuttling material in the loader

Nick

I have a 45 HP tractor with HST, I do lots of loader work. One hand on steering wheel, one hand on FEL lever, one foot on pedal (Fwd or RV). I drive my tractor down the road some too, and find the HST nice for changing speeds as I slide to the right for the big rigs. I test drove a gear drive and an hst at the dealer before purchasing, and they were kind enough to let me dig into their bank so I could see the difference. The HST is so much faster moving between digging, backing, turning and dropping/spreading.

 

[MossRoad]

Soon to be in the market for a 20-32 HP CUT.
Have not had the time to demo any (work Schedule), just arm chair shopping.
I have this far discounted any HST models do to my preconcived notion that they are loud and "herky-Jerky" (My only CUT experiance is on machines of 20+ years ago, or bob cats)
Talked to a CUB/Yanmar and a Kioti dealer, when I mentioned this, they said, No the new HST machines are smoth as silk ? One guy mentioned something about a "clutch" in the HST drive that smooths it out ?

Can anyone shed some light on this ?
I know I need to get out and try some, but it will be a month or 2 till My time is freed up.

Thanks,
Nick

I ran this late 70's IH2500b pretty regularly for about 10 years between 1990 and 2000 and then occasionally for another 5 before selling it to an IH salvage yard. The HST was smooth and responsive and that was a 25 year old machine.


A couple things I would look for in an HST...

Make sure the forward and reverse pedals are on the opposite foot as the turning brakes. Otherwise the brakes are as good as useless for turning. I cannot figure out for the life of me why anyone would design a tractor with the directional pedals and brakes on the same foot.

The IH had a dampening system so that if you yanked your foot off of the directional pedals it would not jerk to a stop, but stop smoothly. My current tractor stops on a dime if you pull your foot off the directional pedals. It can cause a really hard jolt to the operator.

 

[john_bud]

Hi all,
I understand all the advantages of the Hydro but sometimes shear simplicity is the key. A simple hammer always work as long as you can hit the nail and just about nothing to maintain. It just appears to me the condition of the hyd fluid, cleanness, filtration of the sediment and stuff is of utmost importance for proper operation. It looks to me when time is of essence and every second counts one can not discount HST. Hydraulic driven motor is a marvel of engineering indeed. My question is what kind of service can you get or expect from HST transmission if your total use of tractor maybe in the neighbor hood of 30 hrs a year with long storage time without activity? As the adage goes "use it or loose it". looks to me HST has to be used constantly to have a better life expectancy. I hate the darn thing to "dry rut" in storage.

No flow/no pressure= no go and that bothers me. You can see 60 yr old tractor that still keeps on going.. may not be going fast .. but keeps on going.

Just my 2 cent. I appreciate ya'lls opinion.

JC,

JC, If you like simple then you best ditch the gear tractor and get an HST. After all, they have fewer parts and are just basically a variable displacement pump and a hydraulic motor. It just doesn't get any simpler than that! Now the new "40" series Kubota HST-Plus is a new deal with integrated computers and all that, but the basic transmission is still simple.

As for reliability, it's probably 3-5x higher reliability HST vs Gear.

As for operational cost, you will probably go thru 5 clutches on a gear trans and 2 sets of bearings before you have to open the HST. And by that time, you may as well buy a new tractor as the rest of the HST machine will probably be on it's last legs.

As for abuseability - you can easily abuse a gear tractor. I've seen 1 year / 100 hour gear tractors with broken gear teeth and totally toasted clutches. There are reputable reports of abusive users (normally minors, greenhorns or dumb hourly workers) that have smoked clutches in under 40 hours. All it takes is a bright boy or girl slowing down and creeping into a pile by slipping the clutch rather than down shifting and riding it half depressed. sniff sniff, what that smell? smells like a $2000 clutch job!


To address your question of only 30 hours of use per year. Hmmm. That one is harder. Machinery does not like to run then sit. Tractor are more like a good bird dog, only happy when being run ragged! You may find that with an HST the tractor is so easy to use it gets used more! (Well, it could happen!) As long as you don't contaminate the hydro fluid with water the HST will stay happy. As most tractors (gear and HST) use common sump for trans, hydraulics and differential that's going to be an area of concern no matter what you buy.

All I know is in 20 years when you go to sell that tractor with 600 hours - it will probably be a nice one!

jb

 

[JC-jetro]

JC, If you like simple then you best ditch the gear tractor and get an HST. After all, they have fewer parts and are just basically a variable displacement pump and a hydraulic motor. It just doesn't get any simpler than that! Now the new "40" series Kubota HST-Plus is a new deal with integrated computers and all that, but the basic transmission is still simple.


jb

John,

I could not disagree with anything that you said. I need to get an opportunity to open up a hyd pump and motor. The pump reminds me so much of my first pressure washer with cheesy swash plate made out of pot aluminum and cheaply made components. The piston was solid SS but all the piston seals were nylon with spring loaded intake and exhaust valve on the water side. I got a bit of water passed the seal , got mixed with the oil and soupy mess killed the pump in nothing flat. I know the material are a lot better with hyd pump and motor in tractors and such. I just can not see the pump seal last longer that machined gear. I accept all your argument about the novice, inexperienced, careless or may be a "moron" as an operator but think if the operator is good the gear tractor should last longer with very little maintenance if it kept in storage to keep moisture and condensation at bay.

JC,

 

[john_bud]

(Shhhhh don't let it out -> in reality you have to work pretty hard to find a "bad" technology transmission on a new tractor. Differences between operators makes more of an impact on reliability than the whole HST vs gear thing. - but don't let it out that I told you - I have a reputation as an HST bigot to uphold!)

jb

 

[JC-jetro]

(Shhhhh don't let it out -> in reality you have to work pretty hard to find a "bad" technology transmission on a new tractor. Differences between operators makes more of an impact on reliability than the whole HST vs gear thing. - but don't let it out that I told you - I have a reputation as an HST bigot to uphold!)

jb

John,

Capisch.. That'll be our little secret. Just keep up the reputation at all costs

JC,

 

[dfkrug]

I need to get an opportunity to open up a hyd pump and motor. The pump reminds me so much of my first pressure washer with cheesy swash plate made out of pot aluminum and cheaply made components. The piston was solid SS but all the piston seals were nylon with spring loaded intake and exhaust valve on the water side.

I have not opened up a press washer hyd pump (yet), but it sure sounds
different from an HST setup. Take a look at my pix posted in my B21
rebuild thread. The variable displacement pump pistons have no seals...they
are just a close-tolerance fit into the cylinder block. Also, the HST uses
the same fluid as the gearboxes and rear end, but separate filtration.

As for an HST being simpler than a gear trans setup, even a non-electric
HST like my Kubota and Kioti still have full gearboxes and a dry clutch, like
gear. So it does add some more complexity, though not as much as say
the new Kubota HST-plus, or even NH's dual-displacement motor HST with
electric controls. But I do love HSTs.