I have a Kubota L4400 HST and had to drive it on pavement for 6 miles from repair shop. In High gear with full acceleration, it would not climb the hill until I moved to "medium" gear. Appreciate any input from anyone regarding this.
high gear paved road
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azbinder
Gold Member
2 WHEEL DRIVE WHEN ON PAVEMENT ! ! Possibly back off on the HST pedal just a bit. And just asking,
were the brakes fully released?
were the brakes fully released?
jeff9366
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^^^^^^ YES ^^^^^^^
HST is counterintuitive to a certain extent. For more power application to the road you back off the HST pedal. An HST is pump and hydraulic flow technology.
If you have 4-WD tractor be certain you are in 2-WD when powering down the road.
In High gear with full acceleration, it would not climb the hill until I moved to "medium"gear HST range.
This is not abnormal for an HST tractor encountering hills, especially if the HST tractor has tall R1/ag tires.
A traditional clutch and gear tractor MIGHT pull the hill at a higher road speed.
HST is counterintuitive to a certain extent. For more power application to the road you back off the HST pedal. An HST is pump and hydraulic flow technology.
If you have 4-WD tractor be certain you are in 2-WD when powering down the road.
In High gear with full acceleration, it would not climb the hill until I moved to "medium"
This is not abnormal for an HST tractor encountering hills, especially if the HST tractor has tall R1/ag tires.
A traditional clutch and gear tractor MIGHT pull the hill at a higher road speed.
Last edited:
Ken45101
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Define "hill". My M5040 has 4 gears plus "road" and "field" gears. It won't take my driveway in 4th gear (road). The last section needs 2nd gear. Likewise, out on the road requires downshifting on some of the hills.
My driveway averages 10% for 1500 ft.
SDT
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Bingo.
Yet another reason why I do not use liquid ballast.
Cast iron can be added/removed as need indicates.
LouNY
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I believe that this explains it all:
"High gear with full acceleration"
So he is likely using this linked throttle I hear about on these fancy Hydro's.
So pedal to the floor to try and get full rpm's also max's out the transmission speed.
As has been said back off on the hydro pedal for lower gearing and use the hand throttle to get the rpm back up,
shove the hand throttle up till you get the desired rpm for your road speed then start using the hydro pedal, mash it down till the rpm start dropping to far then let up and let the rpm climb back up.
Also engines have a torque peak on one of mine that is around 1750 rpm while pto speed is around 2400 rpm running down the road i'll usually go for around 2100-2200 rpm when I hit a grade I'll use my foot throttle or hand throttle to max or just leave it alone and just listen to the engine she'll pull down fast till 1750-1800 rpm and then hold right there for quite a bit, she may even make the grade and the rpm will start climbing back up or the rpm will drop under 1700 at which point I'll drop a gear or two.
"High gear with full acceleration"
So he is likely using this linked throttle I hear about on these fancy Hydro's.
So pedal to the floor to try and get full rpm's also max's out the transmission speed.
As has been said back off on the hydro pedal for lower gearing and use the hand throttle to get the rpm back up,
shove the hand throttle up till you get the desired rpm for your road speed then start using the hydro pedal, mash it down till the rpm start dropping to far then let up and let the rpm climb back up.
Also engines have a torque peak on one of mine that is around 1750 rpm while pto speed is around 2400 rpm running down the road i'll usually go for around 2100-2200 rpm when I hit a grade I'll use my foot throttle or hand throttle to max or just leave it alone and just listen to the engine she'll pull down fast till 1750-1800 rpm and then hold right there for quite a bit, she may even make the grade and the rpm will start climbing back up or the rpm will drop under 1700 at which point I'll drop a gear or two.
Cycledude
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That a Very common issue for newer HST operators, once you get used to it it won’t seem as bad as it probably does now.
bdhsfz6
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All the HST Kubotas I've owned had this lugging issue on hills. With experience, you learn to deal with it.
My current L6060 HSTC with stall guard and auto throttle advance minimizes the problem by automatically adjusting HST pedal pressure and throttle. The dual range hydro shift feature also helps.
My current L6060 HSTC with stall guard and auto throttle advance minimizes the problem by automatically adjusting HST pedal pressure and throttle. The dual range hydro shift feature also helps.
Hay Dude
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Even higher HP farm tractors with CVT’s lose speed in high range going up hill. “Burying” the CVT knob, like mashing an GST pedal, won’t gain you anything.
MossRoad
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Tx Jim
New Member
I've been associated with farm equipment for nearly 70 yrs. During that time I was employed by a JD dealer for 21 yrs with 13 of those yrs serving as dealer service manager. I rarely witnessed cast iron ballast removed from a tractor in order to lessen tractor weight once it was installed. YMMV
Thanks for all input and recommendations. I will try for sure.
foggy1111
Elite Member
I've always been surprised at how much power it takes to just drive a tractor at top speeds. all that torque power and traction does not help with speed.
LD1
Epic Contributor
I dont know very many tractors at all that can pull a hill in their road gear without lugging.
Lets face it, tractors are VERY LOW HP to weight ratings.
And the weight is killer. My shop is downhill from my house. Separate driveway and about 150 yards apart. In that span there is a hill that gains ~40' of elevation over 200'. And if I have the loader on and an attachment on the back, and my wheel weights (~8600#).....yea it struggles in high range on the HST. Take the loader and wheel weights off and put a light tiller on (~5000)....and I can fly up the hill at near top speed.
But its all math and HP. (I like math). Horsepower 550ft-lbs per second. So to lift a 8600# tractor the 40' elevation of the hill requires 344000ft-lbs
Since a HST is ~80% efficient and my engine makes ~51HP....I am putting about 40HP to the wheels. Which is 22,000ft-lbs/second. 344000/22000 = about 15.6 seconds to climb 40' over a 200' drive. Which means my max speed in theory can only be 12.8 ft/second which translates to about 8-1/2 miles per hour.
Now in lighter trim with no weights, loader, and just a light tiller.....5000# tractor to climb 40' only requires 200,000ft-lbs. Power is the same, 22000ft-lbs/second. I should be able to climb the same 40' in just 9.1 seconds in theory. 200ft long run in 9.1 seconds is 22ft/second. Which is 15MPH. Tractor max speed is just a tick over 16MPH.
My real world experience backs up the math element of HP.
Back before I got this HST tractor I had an old ford 5500 TLB. Thing was a beast @~18000lbs. Had a 3-speed with H and L and that thing seemed gutless climbing the hill. Thought the engine was just old and tired. Had to drop to 1H (7.9mph gear) just to climb the hill. Because 2H (14mph) and 3H (19mph) were just gutless. Would almost stall. With only about 65HP to the wheels.....math tells me 7mph is about all 65hp can muster for the climb. And real world experience backs that up as well. Put my mind a bit at ease that it wasnt a tired engine, but that it was making about the right amount of power it spec'd.
This is also often why I mention "road gear" when people are shopping a couple of tractors in the same platform but with differing HP ratings. Most people often are quick to cite no real tractive advantage to more HP for things like loader work or ground engaging tasks, and that the greater HP is for things like PTO implements. But it can also be a huge asset if you have hills and want to run higher speeds down the road and things like that.
Can figure things backwards too.....40/200 is only a 20% slope (11° angle) and for a 8600# tractor like mine in heavy form (ballasted with loader and heavy implement)....to be able to climb the hill at my max speed of 17mph, Id need 78HP to the wheels, or about 100hp at the engine.
Lets face it, tractors are VERY LOW HP to weight ratings.
And the weight is killer. My shop is downhill from my house. Separate driveway and about 150 yards apart. In that span there is a hill that gains ~40' of elevation over 200'. And if I have the loader on and an attachment on the back, and my wheel weights (~8600#).....yea it struggles in high range on the HST. Take the loader and wheel weights off and put a light tiller on (~5000)....and I can fly up the hill at near top speed.
But its all math and HP. (I like math). Horsepower 550ft-lbs per second. So to lift a 8600# tractor the 40' elevation of the hill requires 344000ft-lbs
Since a HST is ~80% efficient and my engine makes ~51HP....I am putting about 40HP to the wheels. Which is 22,000ft-lbs/second. 344000/22000 = about 15.6 seconds to climb 40' over a 200' drive. Which means my max speed in theory can only be 12.8 ft/second which translates to about 8-1/2 miles per hour.
Now in lighter trim with no weights, loader, and just a light tiller.....5000# tractor to climb 40' only requires 200,000ft-lbs. Power is the same, 22000ft-lbs/second. I should be able to climb the same 40' in just 9.1 seconds in theory. 200ft long run in 9.1 seconds is 22ft/second. Which is 15MPH. Tractor max speed is just a tick over 16MPH.
My real world experience backs up the math element of HP.
Back before I got this HST tractor I had an old ford 5500 TLB. Thing was a beast @~18000lbs. Had a 3-speed with H and L and that thing seemed gutless climbing the hill. Thought the engine was just old and tired. Had to drop to 1H (7.9mph gear) just to climb the hill. Because 2H (14mph) and 3H (19mph) were just gutless. Would almost stall. With only about 65HP to the wheels.....math tells me 7mph is about all 65hp can muster for the climb. And real world experience backs that up as well. Put my mind a bit at ease that it wasnt a tired engine, but that it was making about the right amount of power it spec'd.
This is also often why I mention "road gear" when people are shopping a couple of tractors in the same platform but with differing HP ratings. Most people often are quick to cite no real tractive advantage to more HP for things like loader work or ground engaging tasks, and that the greater HP is for things like PTO implements. But it can also be a huge asset if you have hills and want to run higher speeds down the road and things like that.
Can figure things backwards too.....40/200 is only a 20% slope (11° angle) and for a 8600# tractor like mine in heavy form (ballasted with loader and heavy implement)....to be able to climb the hill at my max speed of 17mph, Id need 78HP to the wheels, or about 100hp at the engine.
LD1
Epic Contributor
Nope, traction and torque doesnt help with speed. But torque applied over time (Horsepower) does. And thats all horsepower is, a mathematical calculation of how much torque can be applied over a given time. 550ft-lbs/second, 33,000ft-lbs/minute
ptsg
Super Member
Just the other day, I drove my 35hp tractor on the road in 4th gear, High range up a 15% hill to go do some mowing. That's 5500-ish lbs between tractor, loader, bucket, front weights, hydraulic winch, filled rear tires and some odds and ends. But then again, that's with a 12x12 transmission, which is an huge difference. Even pulling my loaded trailer, that would probably require a downshift to 3rd gear but that's about it.
I would like to share a video here from a guy here in Portugal with his Kioti DK4510 pulling a fully loaded trailer. Nearly 14000 lbs up a 10 to 15% hill and he did in 3rd gear high range and actually shifted to 4th as the road got flatter. Unfortunately, the video is on a private Facebook group, so I can't really share it here.
I would like to share a video here from a guy here in Portugal with his Kioti DK4510 pulling a fully loaded trailer. Nearly 14000 lbs up a 10 to 15% hill and he did in 3rd gear high range and actually shifted to 4th as the road got flatter. Unfortunately, the video is on a private Facebook group, so I can't really share it here.
