Auto vs shift

[Hay Dude]

in the case of a hydro shuttle vs shuttle shift on a geared tractor, the former is clearly superior. re: gear vs hst wars, it's meaningless to attribute a better or worse scenario,
this is a compact/sub forum, of course hst prevails among members

there is a very good reason why larger utility M series tractors are gear. the hyd shuttle gear is icing on the cake. to say one system is better than the other is naive & meaningless

Actually, most modern large farm tractors are now CVT’s.
Powershifts are declining with each passing year.

 

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Actually, most modern large farm tractors are now CVT’s.
Powershifts are declining with each passing year.

How does the cvt work in a farm tractor?
Is it seamless like in a car and is in chain driven or planetary?

 

[paulsharvey]

C.u.t.s started with less hp than that.
They sold and are successful because of their “compact” size.
I’d rather have a 14 hp tractor that weighs 4000 lbs than a 38 hp tractor that weighs 2500 for anything other than pto work.

This right here is largely said on TBN, but weight and traction alone don't replace Power. There is a bit of a myth that every thing can just be done slower with less power, or go to Low on LMH transmission, and that's just not true. Ground engaging, almost everything has an ideal speed to run, and even just loader work, sometimes medium, with some wheel speed is what you need to get out of a situation.

So, 100%, a 6,000# 50hp might out work a 5,000# 75 hp, but not in all things; and they both will work circles around a 6000# 30 hp.

 

[paulsharvey]

One of the issues with power shuttles, and Shuttles in general is the lack of clarity. What the hell is a GST, a power shift, a hydro shuttle, a power shift.

I have ran many hydralic shuttle shifts on construction equipment, and it's fantastic, and virtually idiot proof. However, not all tractor power shuttles are the same. Some allow changing of gears but not ranges on the fly, others don't. Some are jerky, some aren't.

What I like on a power shuttle for loader work, you are working at half throttle, then you dig into the pile and hammer down on the "gas".

 

[LouNY]

One of the issues with power shuttles, and Shuttles in general is the lack of clarity. What the hell is a GST, a power shift, a hydro shuttle, a power shift.

I have ran many hydralic shuttle shifts on construction equipment, and it's fantastic, and virtually idiot proof. However, not all tractor power shuttles are the same. Some allow changing of gears but not ranges on the fly, others don't. Some are jerky, some aren't.

What I like on a power shuttle for loader work, you are working at half throttle, then you dig into the pile and hammer down on the "gas".

I haven't run much industrial equipment in several years but at that time most of those had torque converters with reverseres.

 

[arrow]

One of the issues with power shuttles, and Shuttles in general is the lack of clarity. What the hell is a GST, a power shift, a hydro shuttle, a power shift.

I have ran many hydralic shuttle shifts on construction equipment, and it's fantastic, and virtually idiot proof. However, not all tractor power shuttles are the same. Some allow changing of gears but not ranges on the fly, others don't. Some are jerky, some aren't.

What I like on a power shuttle for loader work, you are working at half throttle, then you dig into the pile and hammer down on the "gas".

My assertion of weight to power has to do with the industry race to exclaim hp differentials only.
Initially cuts were around 2000 lbs and had less than 25 hp.
Shortly after that like mid to late 80’s, tractors exclaimed more hp but the rest of the tractor didn’t come along.

10 hp advantage for a 6000 lb tractor comes to bear at pto output especially and most definitely includes a speed of work advantage in size of implement. Also, some manufacturers place a larger tire on the same chassis as the lesser hp model giving a distinct advantage in traction and thus workability.

GST is a glide shift transmission which is just another name for a power shuttle.

 

[paulsharvey]

Another note; construction equipment, RPM only matters in regard to power, there is 'generally' no need to maintain a constant RPM for a PTO, with varying speeds.

A power shuttle really is fantastic for loader work, as well as ground engaging, but in some ways, a Hydro can be awesome with PTO impliment, where you need consistent RPM, will you vary ground speed to match conditions (think bush hogging a field, with a boarder line machine, 4mph is fine in the lighter stuff, but we still need 2500 rpm regardless, then we get in some heavier material, and we can feather that Go pedal back to 2 mph, will maintaining RPMs). Loader work, HST is kinda not the ticket; we are running max RPMs, and right when we want the most, digging into the pile, we got nothing left; and we are running 2500 rpms all the time, rather than a higher range at 2000, and just 2500 as we stab into the pile.

 

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In reality, I am running no faster ground speed on the lesser hp model with 8’ cutter deck as I am with the higher hp model with the 10’ . I’m just getting done faster as a result of the cutter swath difference .

 

[paulsharvey]

Not all shuttles allow in motion shifting of gears, some do, within the range.

I've ran TBLs that were true hydralic reversers, but no shift on the fly for gears. I've also used ones that had a roller "knob", 1-3, 1-4, or 1-5, that could be rolled through on the go. I'm not aware of a Cut/utility that allows say, 1-4, and L-M-H on the fly. Another difference; AG; there is often a tight speed range that works best; construction/industrial; we deal with power, and a max speed of maybe 18 mph (maybe 30 on a grader). So, 1, 2, 3 gears can be fine. On a loader, the ability to roll to N, and mash the throttle for higher flow to load a truck is nice.

Another thing; Compacts, nobody really cares about "mileage", where a 10% fuel savings is a Big deal when burning 250 gal per day.

HST is widely understood; clutch maybe but only for PTO/start; no ability to change range on the go, but infinity speed within the range. PST, each make has its own function, and name; which i think causes confusion.

Dry clutch shuttle; i just don't see the point for most people. Straight line work, sure, but its naturally limiting. Also, yes, you can feather a clutch, but at the cost of shorter life, and this isn't a 1985 ranger with a $300 clutch that takes an afternoon to replace; it's a full split, and probably 20+ hours for a pro; and a pretty over whelming task for a DIYer. Just gaskets, O-rings, wiring harness connections, it's a ton to split a machine, and that's if you have the equipment and knowledge

 

[paulsharvey]

Construction, we don't need 16 or 32 speeds; running a bailer, maybe the difference between 3.2mph and 3.6 mph, at PTO rpm is the difference between clogging and smooth bailing.

Same time, take the Jd-110, micro TLB, in a construction setting, it lacked the mobility of a true TLB, with a really low road speed with its HST. Tractor data says it could get to 16.2 mph in high; more like 10-12 in real life, too slow for a municipality to "road" it 5 miles between sewer services.