Today's disaster - rethinking HST

[buck12]

I have not read every post but I will post an HST experience. My lawnmower is a deere GT 235 with the HST pedals and brake are on the same side. Two years ago I was cutting around our pond going downhill to the water like I usually do. When I tried to back up the bank the mower began spinning. The bank was steep enough that the brake was needed to keep the mower from rolling into the pond. This required me to used my toe on the brake and heal on the HST pedal. My heal caught the reverse pedal and the mower got a bath My point is if I ever buy a tractor with HST (current tractor is gear) it will have the brake(s) on one side and the HST pedals on the opposite side.

 

[bigbull338]

as said your talking about 2 differant HSTs.an i would think that things could go wrong with a lawn mower HST more than on as tractor.i trust an like my HST so well that ill never buy another gear tractor.sorry about your accadent.

 

[Baby Grand]

I decide to take the old Craftsman lawntractor up and down the hill on my yard a few times to knock down some winter growth. Fairly steep yard, between 30-35 degrees, perhaps slightly more at the edge.

... Granted, I know that a HST lawn tractor is set up different than a a HST CUT, but if a complete release can happen on the lawn trac., could it ever happen on a CUT? I would hate to find myself barrelling down on of the hills on the property with less than complete control.

I appreciate any feedback!

Wow! 35 degrees is steep! I think I would have used the weed whacker on that bit 'cause I got a yellow streak when it comes to slopes.

From my very limited understanding of HST design and pump behavior, I believe that if the hydro fluid pickup "dipper tube" in the reservoir lifts out of the fluid level, then it's off to the races.

I also believe the hydro fluid in riding mowers is generally a user non serviceable affair, so you probably wouldn't know if the fluid level had dropped due to a slow leak or whatever.

So - I suspect that if the design of an HST tractor allowed the dipper tube to lift out of the fluid at any angle of operation, you could be in for a ride.

2 qualifiers to the above:

Most CUT & SCUT operators check their HST fluid on a regular basis, so low fluid level would be less likely of an occurrence.

That sort of design defect would get flagged by the tractor using community in a way that would hurt sales for that particular manufacturer and bring down the wrath of the liability lawyers and sympathetic jurys such that they never made that mistake again. But I've been wrong before.

-Jim

 

[Code54]

As others said, the good thing about all of this is that you are still alive and well to post the question! Not matter what happened at least we can talk to you about it. Glad you are alright and good luck with the new tractor!!

 

[jake98]

My cheapo lawn tractor hydro picks up speed on a downhill. And with those single brake/clutch pedals you go thru neutral before you get to brake. They're nothing like a real HST.

 

[tsteahr]

Today was a gorgeous day for working in the yard...65 degrees and sunny. So the wife, myself, MIL and a couple of nephews trim some old brush, haul everything to the burn pile and then call it a day...almost.

I decide to take the old Craftsman lawntractor up and down the hill on my yard a few times to knock down some winter growth. Fairly steep yard, between 30-35 degrees, perhaps slightly more at the edge. I have the HST lever all the way down but as soon as I hit the steep part of the slope it takes off...clutch/brake does nothing. Long story short, machine starts to skid, pitches me off, fortunately doesn't roll on me, engine shuts down as soon as I make my less than graceful dismount, and I am left on the ground, skinned, bruised and royally pi$$ed off.

This brings me to my concern and I hope some of you folks with more experience and knowledge can help me out. I am in the market to purchase a new tractor for the place. While I won't be using it to mow the yard, the rest of my property has a few hills and such like the yard. I had been leaning really hard toward HST but after today I am not so sure. Granted, I know that a HST lawn tractor is set up different than a a HST CUT, but if a complete release can happen on the lawn trac., could it ever happen on a CUT? I would hate to find myself barrelling down on of the hills on the property with less than complete control.

I appreciate any feedback!

First off, glad you were not seriuosly hurt. Desending a slope that steep (30 degrees or more) it would be very likely the rear tires of any lawn tractor would loose traction and skid, unless you added substantial rear counterweight. I have skidded down less steep slopes in my yard on a lawn tractor. A little moisture, say from freshly cut grass or thawing ground, only reduces your available traction.

I have to wonder that a brand new lawn tractor would have done the same thing.

If you are going to we working on steep slopes (really anything above about 12-15 dagrees) I think 4wd is essential for safety. Using 4wd is most important when going down hill. On a cut with something in the fel, desending in 2wd means no virtually brakes, unless you have a lot of counterweight on the back, like a back hoe. Even then, why risk it?

Seriously, if you are going to be on those slopes get 4wd. Way to dangerous without.

 

[veresjwv]

I appreciate all the feedback. As I said earlier, I think I ended up in a situation caused by an old lawn mower with a weak HST. I am sure an HST on my upcoming HST purchase shouldn't be an issue. I suppose the instance of HST failure on a slope is more or less a non-issue actually. From the sound of things, everyone has had good experiences on slopes. That was the info I was looking for. Thanks for all of your responses!

One thing that happened to me that I have not seen mentioned here.... Last Spring I was getting rid of some cuttings and was on a lawn using the loader to dispatch a bunch of trimmed limbs. I was on the lawn going down hill in 4 wheel and as I was gaining speed I let off the HST pedal which stopped the wheels and at that moment the turf broke away under the tires and away I went.... I was not free wheeling but sliding like on ice Scared the bejesus out of me:ashamed: But other than that one problem I love my hst and have had it for two years now!

 

[TripleR]

I have not read every post but I will post an HST experience. My lawnmower is a deere GT 235 with the HST pedals and brake are on the same side. Two years ago I was cutting around our pond going downhill to the water like I usually do. When I tried to back up the bank the mower began spinning. The bank was steep enough that the brake was needed to keep the mower from rolling into the pond. This required me to used my toe on the brake and heal on the HST pedal. My heal caught the reverse pedal and the mower got a bath My point is if I ever buy a tractor with HST (current tractor is gear) it will have the brake(s) on one side and the HST pedals on the opposite side.

Brakes and HST pedal on the same side has been a hotly debated issue on these threads with unpleasant results, so I won't go over plowed ground.

My father in law put his John Deere into ten feet of water when he hit the forward instead of reverse pedal as they were side by side. An isolated incident does not make an entire design faulty. I used a John Deere 425 with the brake on the right and our John Deere 2305 has the brake on the left. Our BX2660 and L5030 have the HST and brake on the right side. I don't see a safety issue with any of them.

As to the OP, we run all types of tractors on very hilly terrain and I feel much safer and more in control with an HST, but don't really have problems with the geared units.

 

[SandburRanch]

If you lockup both back wheels, your directional stability will be lost. It's like having a big ball bearing in the back instead of tires. This applies to any type of vehicle. It's part of the reason we have ABS on cars.

I think Code54 is right on track with his comments. I wouldn't let this turn me against an HST. A gear unit could do the same thing. You might be leaving the clutch out and in gear for engine braking, but if you're sliding faster than the wheels are turning, you end up with the same situation.

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K7LN and I may have attended the same or similar seminars.

On vehicles of this category there is a rule of thumb, for whatever a thumb rule is worth. It states that- the wheels with the least traction always take the lead. It was demonstrated in a seminar I attended and sure changed everyone's mind that thought they knew everything. Well, nearly everyone except for a few seasoned truckers and the instructor sensed this because he had been there before with those folks and knowing he was correct, because he just demonstrated it with an 18 wheeler, simply moved on.

So with this in mind I can't see any difference at the moment whether you have hydro or gear. If the rear wheels are sliding they have less traction and will tend to take the lead. And if it continues the tractor, car or truck will eventually do a 180 unless it rolls first.

I've not tried this but just off hand it seems that with a hydro or geared tractor acceleration would correct the situation and that may be easier with the hydro unit.

 

[TripleR]

---------------------------------------------------------------------
K7LN and I may have attended the same or similar seminars.

On vehicles of this category there is a rule of thumb, for whatever a thumb rule is worth. It states that- the wheels with the least traction always take the lead. It was demonstrated in a seminar I attended and sure changed everyone's mind that thought they knew everything. Well, nearly everyone except for a few seasoned truckers and the instructor sensed this because he had been there before with those folks and knowing he was correct, because he just demonstrated it with an 18 wheeler, simply moved on.

So with this in mind I can't see any difference at the moment whether you have hydro or gear. If the rear wheels are sliding they have less traction and will tend to take the lead. And if it continues the tractor, car or truck will eventually do a 180 unless it rolls first.

I've not tried this but just off hand it seems that with a hydro or geared tractor acceleration would correct the situation and that may be easier with the hydro unit.

We have a very steep road behind our house. For years, we used 2WD HST mowers and our 2WD Ford NAA to mow around different areas on our levies etc. They went up the hill quite easily, but the trip back down.

The only good way back to our house was a half mile road trip to a gate, so at the end of a long day, I would often choose the "slide" down the hill.

What you describe worked the "best" to have any semblance of control and was "easier" with HST. There still was no way to avoid flying gravel and fairly significant pucker factor.

As soon as I could afford to, I got 4WD's and use 2WD only on our flat land farm where they are very happy.

 

[First one]

Sounds like you hard quite a ride, glad you were not hurt to bad.
(..engine kill switch stopped it as soon as I left the seat.)

Sometimes those little switches can save you from a far more serious injury , then if you had unhooked it. There a pain in the arse most of the time but when you need them it's nice to know they work.
I still think that the HST is easyer to use on hills . With a gear tractor you had better be in the right gear going up , so you don't have to shift or coming down, or your going to be riding the brake alot.:2cents:

 

[ihuntbear]

we have a 55 hp hst bota at work .One day we were bush bogging on the highway under a bridge.The driver was going uphill under the bridge when all of a sudden the tractor seemed like it went into neutral .On the way down the hill going toward the road he struck the cement pillar breaking the rearend in two.We called the dealer,they said hst tractors aren't supposed to go up or down a hill greater than 22 degrees because there is a safety pop off valve in the trans to keep from starving for hyd fluid.They went to the hill and measured the degrees,It was 25 degreees and they voided the warenty

 

[jenkinsph]

I don't think I would call the tiny litte grip thingy on a lawn mower "brakes". More like something to hold it still while fueling.:laughing:

Really depends on the lawnmower, mine has wet disc brakes. That said I have no plans to run up and down a long 35 degree slope either.

 

[TripleR]

we have a 55 hp hst bota at work .One day we were bush bogging on the highway under a bridge.The driver was going uphill under the bridge when all of a sudden the tractor seemed like it went into neutral .On the way down the hill going toward the road he struck the cement pillar breaking the rearend in two.We called the dealer,they said hst tractors aren't supposed to go up or down a hill greater than 22 degrees because there is a safety pop off valve in the trans to keep from starving for hyd fluid.They went to the hill and measured the degrees,It was 25 degrees and they voided the warranty

Interesting, I have run my L5030 and BX's up grades steeper than 25% and never had a problem.

 

[escavader]

GREG FENDER,
Im curious to which model you have.I know on my older geared craftsman the clutch and brake are one and i learned long ago DONT STEP ON THAT PEDDLE ON A HILL It is a hydostic tranny as you state,just wondering if that pedal kicks it to neutral as well.
ALAN

 

[whistlepig]

This is probably one of those situations where we just simply have differing opinions or experiences, and I appreciate the ability to discuss such things here. It gives us all a chance to hear the different opinions and make our own decissions.

In the OP's situation: trying to stop a run-away on a steep slope: I would prefer to have both rear wheels lock and not be able to steer than to be able to steer while the machine proceeded down the hill. Admitedly, I am thinking about my steep areas BUT there are probably situations where I would prefer to steer also.

I agree that our experiences are different. I think that the both of us are concerned about the OP's safety on a hill. I wouldn't call it differing opinions though. I would call it sharing opinions.

 

[Dr_Zinj]

did you see any skid marks on the grass,ie. to see if you were sliding?

Bet there were skid marks in his underwear. That's a scary situation no matter what the cause.

I had a similar situation going in a different direction when hauling an overloaded wagon of wood. 2 wheel drive tractor, steep slope, and the drive wheels broke traction almost at the top of the hill. Wagon pulled everything down hill, wheels spinning, and jackknifed about 3/4ers of the way down. Trailer went over on it's side and stopped the tractor without flipping it; but I was shaking like a leaf for an hour afterward.

 

[Ford tractor]

I don't think you can really extrapolate lawn mowers to tractors

 

[jenkinsph]

I don't think you can really extrapolate lawn mowers to tractors

Bet you would have remembered this if it happened to you.

 

[crazyal]

When I first got my Kubota I made the mistake of going down the driveway in 2wd. I don't have loaded tires and the fel lightens up the rear quite a bit. The rear wheels started to skid so I quickly put the tractor into 4wd. Since then I now have a rear ballast box. If you're looking into getting a tractor it sounds like you really need 4wd or at least to fill your rear tires.