PT1845 Hillclimb

[Sedgewood]

A couple of weeks ago I was out roughcut mowing the back slope on my neighbors pond. This slope hadn't been mowed since the pond was built 15 years ago and was getting quite overgrown with brush and brambles. I roughly measured the slope at 25 degrees with a couple 30 degree spots. I found that I really couldn't mow diagonally up slope without excessive side slip and tearing up the ground. So I cleared some escape routes at the bottom in the woods and mowed as nearly horizontally as I could while side slipping toward the trees, then took the nearest escape when I got near the bottom (gotta watch that downhill leaning FOPS relative to trees)

All went pretty well with some puckers since I'm not used to being on such steep slopes. But here's the kicker I wasn't expecting. After each pass I had to go all the way around and start from the top again. There was just no way to climb straight up the slope to the top. Traction was not an issue but the wheel motors stalled at what seemed just shy of the 25 degrees no matter my throttle setting or treadle position. I was lucky to have an escape route when I discovered this. Sure wouldn't want to be seen towing a PT!

Charlie, have you discovered this limit on your 1845? Has anyone else found the limit on other machines? I think I'd like the limit a little higher because I can also stall the motors pushing a bucket uphill trying to fill it.

 

[duane]

Sedgewood,

I'm wondering if you hit the relief valve setpoint in the variable volume pump. The amount of hydraulic pressure to provide the torque to climb the slope must be fairly high. Does your engine bog down at the point of stall? Were you climbing the slope with your PTO off?.

Duane

 

[Sedgewood]

Duane
<font color=red>I'm wondering if you hit the relief valve setpoint in the variable volume pump.</font color=red>
Yes I would think that is the limiting factor, together with oil viscosity. My impression is it has slightly more torque when the oil is cold.
<font color=red>Does your engine bog down at the point of stall?</font color=red>
No.
<font color=red>Were you climbing the slope with your PTO off?.</font color=red>
Yes and no. I tried it both ways. It makes no difference. They are on separate pumps and there seems to be no lack of engine power.

The PT1845 is rated for 40 degrees with dual wheels (23-8.50x12) which are a smaller diameter than the singles I have (26-12x12) and I wonder if the smaller diameter of the duals if enough to make the difference.

 

[MossRoad]

So your tires are taller? This would change the gearing for sure, making your machine faster, but less torquey (torquey is a word in my vocabulary). How much less torquey, I do not know.

 

[Charlie_Iliff]

John:
I have not encountered the wheel motor stall you describe. I have done a lot of steep work, but my limit has always been traction. I haven't tried to measure the slopes, but a couple of times I have slid some distance with the wheels stopped. I often have been unable to climb, but always with a few spinning.
I have turf tires, and until last week was running too much air pressure. I haven't done any slope work since I dropped it at Terry Estep's recommendation. If that doesn't work, I'll be considering bar treads on at least the fronts.
You may want to talk to PT and ask where to plumb in a gauge and see if the relief valve is opening early.