How does an HST compare in pulling power with the same tractor and a gear trans?

   / How does an HST compare in pulling power with the same tractor and a gear trans? #271  
Clutches are OK if you don't have a clutch rider and
in this case you replace quit often. Not every one knows
how to use a clutch and with an HST a forward pedal and
a backward pedal. My old 74 Ford is 3 speed and I had to
replace the clutch when I got it clutch parts very cheap
compared to clutch parts now as I got a 40% discount:unsure:


willy
 
   / How does an HST compare in pulling power with the same tractor and a gear trans? #272  
I don’t want to pay for either of these repairs, but my AGCO dealer is telling me a modern 150-300HP power shift rebuild is more expensive than a remanufactured CVT swap.
 
   / How does an HST compare in pulling power with the same tractor and a gear trans? #273  
More controllable torque delivery yes, but as you go into adding ballast and counterweight, loader and a loader load you fairly promptly encounter situations where you cant apply enough torque to the wheels to move - even in low range. The relief valve in the HST just opens and youve got to find a work around to proceed. Typically the max wheel torque deliverable from a comparable gear tractor is much higher. I find that ~ 2nd or 3rd gear of an 8 speed will exceed the torque limit of a 3 range HST.

It’s all about torque delivery control to start a load moving without traction loss which a HST can do much better.
 
   / How does an HST compare in pulling power with the same tractor and a gear trans? #274  
It’s all about torque delivery control to start a load moving without traction loss which a HST can do much better.
That entirely depends on the surface you are on and the type of tires you have as well as tractive effort (weight of the tractor) more than anything else, so I disagree with your premise. Besides, power transmission on a gear drive tractor isn't instant at all. There is a ramp up as the clutch is engaged or the wet pack travelling clutch engages and that is an always occurrence. Driving power to the wheels is never an on-off situation.

Even with my gear drive units, transitioning from forward to reverse (hydraulic wet pack shuttle) is always a progressive motion as the wet pack attains clamping pressure and locks the plates.
 
   / How does an HST compare in pulling power with the same tractor and a gear trans? #275  
I have never encountered the inability to spin the tires in low range on a HST. Therefore that argument is invalid.

Medium range and high range, yes. But low range, never an issue.

And thats on my MX5100. Bare tractor ~3900#, 720# of fluid in the tires, 600# of rear wheel weights, 1620# bushhog on the back, and a 1300# loader. (not sure if that loader weight counts the bucket, if not the bucket is ~400#)

So a ~8000-8500# tractor 4wd sitting on R1's.....and I can spin the tires in low. Dont know how a gear tractor is gonna ***** that? Low range is equal to gears 1-4 on the MX gear trans. 5 and 6th is comparable to Meduim range.

So if a 8000# mx cant slip the tires in 6th gear, it stands to reason I can in meduim range.
 
   / How does an HST compare in pulling power with the same tractor and a gear trans? #276  
Heck, I have yet to see an HST tractor with over 3000 hours that hasn't been worked on the HST at one point or another.
4500+ hours never touched the HST or motor. Wore out most other parts......
 
   / How does an HST compare in pulling power with the same tractor and a gear trans? #277  
My Kubota B20 3speed gear range failed at 3000hrs before the HST did.

One is not better than another just different. Like them both.

It gets pointed out that HST is less efficient than gear. But having infinite speeds more than makes up for the difference. With a gear transmission you can get close but never perfect so loss of available hp too. Working my hillside farm the load the tractor see is always changing requiring changing gears with any transmission. Loader work is frequent and HST is king.
 
   / How does an HST compare in pulling power with the same tractor and a gear trans? #278  
My Kubota B20 3speed gear range failed at 3000hrs before the HST did.

One is not better than another just different. Like them both.

It gets pointed out that HST is less efficient than gear. But having infinite speeds more than makes up for the difference. With a gear transmission you can get close but never perfect so loss of available hp too. Working my hillside farm the load the tractor see is always changing requiring changing gears with any transmission. Loader work is frequent and HST is king.

I’ve been making that point for a long time and it mostly falls on deaf ears. If you had a 12 or 16 speed transmission it’s not much of a problem but when you only have 8 gears the right speed is never available. I’m not saying it can’t work but when you’re bush hogging and the optimal speed is 4mpg but your gear selection is 3 mph or 5mph. The HST can go 4mph where the gear transmission is either going to have to take the 5mph gear and throttle back which is going to lose power and sacrifice cut quality or just drive 3mph. Doing the whole job at 3 mph vs 4 mph is a pretty big difference. Also when you’re bush hogging you might want to run 3,4,5 and back to 3 mph depending on the conditions. The HST can do that where the geared trans is constantly changing gears. You could just set the gear trans at 3mph and forget it but you’re loosing productivity that way.
 
Last edited:
   / How does an HST compare in pulling power with the same tractor and a gear trans? #279  
The results of this thread so far; Those who love geared transmissions still love them. Those who love HST's still love them. And some of us could live quite happily with either. Pretty much exactly the same results as before the thread was started.:)
I agree, both do the same jobs, in general the HST is easier to use for most tasks, in general the geared tractor is the most economical from a 1st cost and operational standpoint. i have spent my life working with old geared 2wd tractors (and by geared i mean sticks on the tunnel not shuttle shift), the advent of shuttle shift / power shuttle / HST have been a game changer is ease of use. but we are getting further and further from the lump of iron that you put fuel into and it always worked.

IMO the HST is the furthest along the spectrum of more complicated and more parts to fail. for a SCUT why not HST, for a CUT, what are you doing with it and how well trained will the operator be? for a UT the decision is even more dependant on the task to be performed. there is also the issue of not all HSTs or Shuttle transmissions being equal.

I do not buy into the idea that a geared tractor will out pull a HST, but it will generate less heat / wear on the tractor and eat less fuel when pulling a load.
 
   / How does an HST compare in pulling power with the same tractor and a gear trans? #280  
My Kubota B20 3speed gear range failed at 3000hrs before the HST did.

One is not better than another just different. Like them both.

It gets pointed out that HST is less efficient than gear. But having infinite speeds more than makes up for the difference. With a gear transmission you can get close but never perfect so loss of available hp too. Working my hillside farm the load the tractor see is always changing requiring changing gears with any transmission. Loader work is frequent and HST is king.
Totally FALSE. And the clutch/gear fanboys are always quick to spew that garbage.

Simply saying inefficient or less efficient without a clarifier in inaccurate and incomplete. Inefficient at WHAT?

Less efficient at transmitting power to the ground? Sure.....but thats IT. How does one define efficient?

The definition of inefficient is:
not achieving maximum productivity; wasting or failing to make the best use of time or resources.

When you mow with a gear tractor, and have to waste time on turns and direction changes and gear changes......that certainly sounds like a textbook definition of inefficient to me.

A zeroturn is a hydrostat. They make geared lawn tractors. Is anyone out there arguing that a gear driven lawn tractor is more efficient than a zeroturn?

Skidloaders are HST. Precision of control, speed, direction changes, etc. Is anyone out there claiming them to be inefficient at moving dirt?

IF you are plowing a 100 acre field with a bottom plow.....sure a gear tractor is the efficient choice. But how many of us with a under 60hp tractor are doing a SINGLE task like that where speed and direction changes arent common?
 
Last edited:
 
Top