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]

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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.

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.