Traction Advice/wisdom needed for slope operation problems with my PT 1430....

[Hawksledge]

OK ... putting this out hoping for some great PowerTrac owners wisdom from this esteemed group .... Here is my issue: We live on a mountain, so pretty much no flat land around our property. We have access "roads" cut in to allow our PT 1430 to access most of the common areas where we need to work around the house/property, but these access roads are basically dirt/clay fill with some gravel compacted in the mix, and can be at a 25% grade over many sections (so 3ft of rise/fall in elevation over a 12ft level horizontal distance). Now the PT1430 can handle this fine at the start of the work session - including up/down with loaded bucket of rock or pulling a log or trailer. But here is where the problems start .... AFTER the PT has gotten all warmed-up, (oil temp over ~160) when attempting to go up the slope on steep part of the roads - loaded or empty, one or both FRONT wheels will start to spin and dig a nice hole under the tire(s), while the rear wheels will not be turning/spinning anymore. I have been running TRU-POWER AG tread/lug tires. If I stop and let the PT cool for a while, then re-start and make a new run up the hill it will generally do better and make it -- until it gets back to full "warm" again. Naturally, the road conditions can make the situation much worse -- ie: wet and muddy top surface of the road will end-up slipping much sooner, and extremely dry conditions will also allow the tire "digging" to begin a little sooner as well.

SO ... PLEASE ... SUGGESTIONS WELCOME on what options/approaches to consider .... (1) improve the road surface for better traction -- ie: add compacted crusher run? Or, try the grid-cell permeable solutions that can be staked-down on the slope and filled with gravel? Or (2) start making adjustments to the PT 1430 to better manage this issue? -- ie: change in tires?, pressure?, filled-tires?, different/heavier hydraulic oil?, more oil cooling? Or (3) when the PT gets to hot to climb the hill .... stop work for a few hours and go have some cold beverage myself (this option is really hurting my productivity).

Thanks!

 

[woodlandfarms]

OK, backing up....

What pressure is your tires at? And how old are your tires?

Have you ever used a thermometer to measure your hydrualic oil temp? This is a stupid failing on the PT Design watch. the temp you are reporting is not your hydraulic but your engine temp. You need to use either a laser thermometer or a oil thermometer and dip it into your oil tank under the seat. That will tell us how hot you are running. I assume that when you say you get warmed up that the fan on the engine hood is running?

Did you buy the machine new? Have you re-run any of your hoses?

If a tire breaks free, pressure on that line is reduced so the other tire (which should be your opposite rear) would not spin. or at least not as much.

So lets go to operation. You know that if you want to climb a steep hill you do not mash the pedal down, but let up on the pedal? It is counter intuitive but a hydraulic tractor gets better oomph when the pedal is lightly pressed and not heavily pressed. I tend to mash the pedal momentarily when I start to bog down, then realize that letting it off and "creeping" will get me where I want to go without spins.

Anyway, answer these questions and it will give us all some guidance.

 

[MossRoad]

Hmmm....

That's odd that your fronts would have enough power to break loose with hot oil. Seems you'd have less power with hot oil than cold oil. At least, that's been my experience with my PT425...

Just for giggles, next time it happens, back down the hill, turn around and try backing up the hill and see what happens.

 

[SpringHollow]

You also might try bypassing the temperature solenoid for the cooling fan so that it is always on. Upgrading the fan might be an option as well.

I installed a thermometer into my tank cover/tank. As Carl says, it really does help to know what the temps are.

Ken

 

[MossRoad]

......
So lets go to operation. You know that if you want to climb a steep hill you do not mash the pedal down, but let up on the pedal? ....

That's a good point to remember. And something that's learned either by accident, keen observation, or word of mouth. I figured it out on my hills, but mentioned it here many years ago as what I observed, and that's when the discussion started and I got the explanation as to "why".

For more torque to the wheels, let OFF the pedal. Its extremely counter-intuitive. But its something you learn that becomes automatic after just a few hours of operation once you start paying attention to it.

 

[ponytug]

Welcome to the club- we are getting jackets made!

25% grade shouldn't be that bad for your 1430. I suspect that it is mostly a traction issue. Compacted 3/4"- would help, as would compacting what you have, if it has enough rock in it.

To WoodlandFarm's point, you do want to have the engine at top rpm, get some momentum, and then just barely step on the forward lever as the going gets tough. I would second MossRoad's suggestion of changing front to back. That often helps me, as does having a wide open throttle, but just barely pressing the "forward" lever. For me, it is mostly a traction issue with the clay and fractured rock. Wet, it is slippery, and dry, it is friable and crumbles, causing the wheels to spin out. There's no great solution that I have found. I suspect that there is perhaps also a leakage issue in the drive pump or motors, maybe due to wear.

Easy does it goes a long way. It almost never makes things any better for me to let the wheels spin. As soon as they do, I back off on the forward lever, and just inch my way through the tricky bits. Easy does it for me. My challenge is pushing the 72" brush cutter up a 30 degree slope of mine.

Let us know how it goes and if any of this is helpful.

All the best,

Peter

 

[KentT]

I suspect that there is perhaps also a leakage issue in the drive pump or motors, maybe due to wear.

IMO, the expensive but more permanent solution would be to put larger wheel motors on it -- something in the 25-28ci range. That's my plan for mine, reusing the 28.3ci ones from my burned 425, if they are rebuildable...

 

[MossRoad]

3 foot rise in 12 foot run is what, about 14 degrees?

Here's a handy chart....

 

[ponytug]

Or you can just do the math on the arcsin(3/12), i.e. the sin[SUP]-1[/SUP](3/12)= 14.4 degrees.

That's partly why I suggested that it should be well within the capabilities of the 1430.

I'm not sure therefore that higher torque motors are the solution.

All the best,

Peter

 

[MossRoad]

MATH! No one told me there was going to be a test today! AAAAAaaaaaaaaaa!!!!!! :laughing:

Sooo.. have some beers and don't think too hard on this...

The green line represents a 45% GRADE.
The red line represents a 45 DEGREE ANGLE.

Can you drive your tractor across a side slope on that red line?

There's been several discussions on TBN in mowing threads, trailer hauling threads, etc... regarding grade VS angle. I don't think a lot of people comprehend or appreciate that Power Trac make a 45 DEGREE slope mower....

Not 45% GRADE......... 45 DEGREES.

That's insane....