Comparison HST vs. Shuttle

[mike69440]

Since we're talking about CUTs here, most of them have a mechanical shuttle in which case, the HST equipped models will have more than an edge. Hst will be the cat's meow compared to using a clutch all day.

I think someone put it well when they said that if you have to ask what kind of transmission you need, you need a hydro. Unless you've done the research and KNOW that gears is what you want, go HST.

Just to add, operate the machine and spend some time playing in a dirt pile before you buy. You would be foolish not to, as you choice could be a very costly mistake. Don't let anyone tell you what you like, listen to recommendations, but you decide.
Do you like a manual transmission in a truck or car?

The most difficult to operate transmission is straight non Syncro gear Trans, (They stink, I'm not that old school) Next is Syncro Shuttle with reverser, then GST or Other Hydraulic power reverse type, Finally there is CVT and HST transmissions. I have Syncro Shuttle with reverser and a GST, our HST is on the RTV900 and a blessing.
Sometimes I wish I had HST, but more than 1/2 the time I like my gears.
Reasons I generally do not want HST is:
Power loss
Many whine
You need to run at Higher RPM



That said, The an HST Plus or I would expect the new Yanmar setup, are like a really good automatic in a car, Very nice.

 

[1stDeuce]

My MF is synchro-shuttle, meaning clutch to shift from forward to reverse in any gear. NONE of the actual gears (1-4) or rangers (Crawl, Low, High) are synchronized, so you have to stop to shift gears to speed up, which I find terribly annoying when doing work that requires slow speed, then some traveling, then more slow speed. Lots of clutch slipping to get it moving again in 4th gear high for some road speed, but at least no whine from the HST, and it'll power up any hill around in high without slowing down.

I'm doing a LOT of loader work right now on sloped/uneven terrain, and I'm really wishing it was a hydrostatic. It would be so nice to just rock the pedal forward and backward, and have the tractor stay where I release the pedal. And if I am moving farther, and want to go a little faster, rock the pedal farther...
I will say that aside from the current situation of loader work on uneven terrain, I've been more than content with the Synchro shuttle.

If I ever replace this tractor, I'll probably get an HST. I won't miss the small amount of power that it uses because I'm nowhere near maxing out the tractor in everyday usage, and if you are, then you probably should have bought the next larger hp anyway.

 

[SSdoxie]

If this said "10 percent", instead of "10 hp", I'd agree. A 30 hp HST tractor isn't losing 10 hp to the HST drive, and a 30 hp gear tractor isn't getting 50% better fuel economy than its HST counterpart.

It's usually around 2-4 hp no where near 10 hp. Maybe that much when you get well above 100 hp tho.

To get a more true idea of power loss through HST compare PTO HP of both gear and like model HST. That difference in lower HST pto HP is what the charge pump/replenishing circuit is using from the engine to keep HST at full working capacity, replacing internal leakage (pump inefficiency). If internal leakage exceeds charge pump flow the HST stalls and you have zero HP to the ground drive. Most CUTS have a 3 - 5% efficiency loss as compared to their gear drive counterpart.

 

[Grandad4]

Most CUTS have a 3 - 5% efficiency loss as compared to their gear drive counterpart.

By subjective impression, that does seem sensible to me. Moreover, Kubota has published the engine gross, engine net, gear drive PTO and HST PTO horsepower numbers for their tractors for many years. For my L4610 for instance, those numbers, in order, were: 47.8, 46.0, 40.5 and 39.0. So they claim the difference due the HST is 1.5 hp, or 3.2% of engine net hp. (The current models show a similar pattern.) Just in everyday operation, that seems believable to me because the engine loading from HST operation just isn't really noticeable, unless you do something odd, like try to make a quick start in road gear with the engine at idle. Of course, you'd also stall a gear tractor under those same conditions. I expect having a surplus of horsepower to begin with makes a difference, too.

 

[boggen]

think of it as....

1 handle steering wheel
1 hand FEL joystick or 3pt hitch lever
1 left foot split brakes (2 peddles side by side, 1 for left rear tire, 1 for right rear tire)
1 right foot go peddle / hst peddle / gas peddle

with tractors for average person (not farmers in the fields) it is a lot of backwards / forwards motion for jack of all trades unit.

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the areas i hate the most are.... use FEL with chain/strap on it as i lift something up. and if i can just get another 1" maybe 2" inches nearer to truck the object will clear the side of truck and be able to lift object down. (trying to pull/push object over side = to heavy to really even think about trying). of course 1 or all the tires on tractor are in a rut / pot hole. in this instance i want to make sure i have brakes slightly applied, and barely inch forward, with ability to slam on the brakes to keep rolling any forward.

other examples of above, is use of a pole boom on FEL or on rear end and dealing with trailer or truck and moving stuff. other examples might be backing up to something maybe an implement to hook it up, or have already something hooked up to 3pt hitch and trying to backup against, shed, tree, home, edge of driveway. and difference backing up is either rolling down hill/ditch or putting extra ruts in yard. or banging into shed door as you attempt to remove snow in front of it. due to unable to accurately control the tractor forward/reverse moment. being on flat ground that is hard that is easy peasy. it is the ruts, pot holes, coming in at odd angles, etc... is were the issues come in at.

lining up a Post hole digger on a fence line. ya there are some section nice and straight but for me, i got culverts, ditches, hills, run off grass areas, and everything else. trying to inch your way back and forth and ugly angle to boot can be rather difficult. granted most folks already go with a larger auger bit to tamp dirt around the posts, but after so many holes dug you bound to have missed drill a bit to much. trying to rock tractor back and forth on uneven ground for the right spot just to much if the brakes and transmission do not really allow for the fine point percussion work.

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other issues that come up is say finishing mower to mow lawn, to rotoary cutter, to box blade, to rear blade, to snow blower. say grass is to thick and engine starting to lug. so you goto a lower gear. but then you fell like you are a turtle crawling along, as you are going slower there is abit more strength needed to turn the front wheels. even though you have power steering. a transmission were you can adjust speed and still maintain constant power / engine RPM's is where the issue comes up. in a gear transmission, you can speed up / slow down by adjusting engine RPM's but then PTO attachments and hydrualics for FEL and 3pt speed up/slow down with the engine RPM's.

for a HST or like transmission. you still keep the engine RPM's the same, but increase/decrease the power to the wheels by how fast you want to go. OTHER WORDS. set engine RPM's for correct RPM's for finishing mower, rotatory cutter/mower, snow blower, etc... and you adjust the MPH of tractor accordingly to maximize how fast you can go.

for example this farm, i have a lot hills, high spots and low spots. and grass will grow taller/thicker in the low wet spot areas, and not grow hardly in top of hills. i can be a speed demon on the top of hills while mowing and get a good cut, but then i come down to the bottom of the hill and need to slow down if i do not i barely cut the grass, mower gets clogged up with grass, and i bog down the the engine, and belts start slipping on the finishing mower deck. OTHER WORDS. i do not want to slow down the RPM's of the mower deck, but simply change how fast i mow. and in that i do not want to touch the engine RPM speed. gear transmission i am stuck at gear ratios, either to slow or to fast, with HST i can find some place in the middle.

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FEL (front end loader work) = lots of driving forwards, then suddenly reversing. due to most times you are digging into a hill or digging a hole. or scraping up crud, and then you need to drive to a truck bed, trailer, brush pile, dump area on property to dump it. each time is forward and reverse. in some cases i drive forward into pile of stuff, reverse my way all the way to other destination and then finally drive forward to dump the stuff.

drive way maintenance (box blade, rear blade, clearing snow, etc..) constantly turning around 180 degrees and not wanting to get on yard, or tear up the ditches. (not wanting to create more work for yourself) a good chance you may drive forward with something on 3pt hitch, then just reverse all the way back down the driveway or to next section of driveway. then driving forward again.

shuttle shift were there is a lever beside the steering wheel to go from forward/reverse, to a HST peddle or peddles to go forward to reverse quickly and easily is what is wanted. so you can be safer backing up without need to turn around multi times.

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in above examples having same speed forward and reverse can be rather nice. if not you feel it, when suddenly reverse becomes really slow. and you fight yourself should i do a 180 turn here, then another 180 degree turn at opposite end to possibly make it quicker, or do i slowly backup or take my eyes off what is behind me as i shift through gears to go in reverse faster.

above notation of same speed forward and backwards, you might see "power reversing" to describe this function of transmission.

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sync'ed vs non synced transmission = synced, clutch goes in, and you move lever and there is no bam bam crunch crunch / crash box. with a non synced transmission you are more likely need to come to a full stop then switch gears. or you risk grinding gears.

in old manual cars/trucks/tractors. you had a clutch peddle you always had to push down before changing gears. this is for most part gone in manual gear transmissions. as in needing to push in the clutch each and every time. but there still might be an instance were you still need to press in the clutch, brake, and go / gas peddle. so you can barely inch your way forward/reverse. some times there is also a button to dis-engage the clutch. so you have 1 foot brake, 1 foot go/gas peddle. hopefully the button is either on FEL joystick and/or on the range selector/gear shiftier. i do not remember seeing any for the 3pt hitch levers or rear remote hydraulic lines.

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diff lock / differential lock. = locks both rear wheels together so they turn exactly the same. helps to get yourself unstuck at least me.

normally when getting myself unstuck, i heavly rely on split rear brake peddles. and keep RPM's low-ish (within reason), and use the split rear brakes, to try and keep the rear wheels turning at same speed, or cause one rear tire to spin faster if it is actually eating through the mud moving me forward. or cause one tire to come to a near stand still if it is just spinning in mud going no were while other rear tire is biting in and moving me.

i do not like gear transmission and getting unstuck. due to the fact i end up in to low of a gear or to high of a gear. when i do end up stuck. and trying to control the rear tire speeds to get me up and out and moving again. an HST or like hydraulic transmission at least for me is easier to control how much and if all possible keep the rear tires from slipping at all as i get my self unstuck. due to hands normally on steering wheel and either on FEL or 3pt hitch and i just do not have another foot/hand to use to adjust engine RPM's.

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hydraulic transmission (HST / shuttle) do not cause engine to bog down and die like old gear transmission tractors. instead a by pass valve opens up. when you put to much load on things. and there really is no DUMMY light, like old manual gear transmission when engine bogs downs and dies. as a result. most folks need experience using given unit. to find out which range to use (low, med, high) to keep there speed up and still have some power to use. it would be nice if manufactures put a gauge like gas tank gauge. to show how much the by pass valve has opened. so folks can decide when and if to shift to a lower range, and/or go slower. so they could maximize an HST transmission.

 

[johncanfield]

I've owned a Kubota L2900 GST (shuttle shift) for 20 years and just replaced it with a Deere 4720 (HST). It was a bit strange pushing one pedal for forward and one for reverse and I wasn't sure I made a good choice. After about two hours in the seat I was thrilled! Moving my right foot six inches for forward/reverse beats taking my left hand off the steering wheel to move a lever. For loader and box blade work you can't beat it. For farming gears are good.