Mowing Power Trac Mowing Performance

Sedgewood · Apr 22, 2002

If I may I would like to continue this discussion from the closed thread "Power Trac PT425"

Reds said: I also noticed that the front half of the tractor seems to be sliding sideways (dowhill) as i move across the hill. I'm not sure why.

 MossRoad responded: That is an interesting comment. I've noticed that on sideslopes where I lose traction due to snow or wet grass, the machine tends to want to crab across the hill, with the front wheels pointed slightly up hill and the rears silghtly downhill. The more I want to correct it by steering uphill, since the unit articulates in the middle, actually agravates the situation.

This may be a bit of an aside but I've found the 1845 tends to crab in really muddy going and attribute it to the sort of positraction front & rear effect created by the hydraulics. I once had a Ford Bronco that I ordered with positraction front & rear. You couldn't stick it but then again you never knew just where you'd end up because of the crabbing and the 1845 feels similar when all 4 wheels are slipping & gripping.

Just how steep is this slope? Here's a handy diagram to help figure it out.

You describe a method for determining PERCENT slope, which is the way I've always seen road grades etc expressed. Throughout the threads here at TBN and on the Power Trac literature slopes are expressed in DEGREES, which has confused me a bit.

PTRich · Apr 22, 2002

Reds:
You described that the front of your tractor slips down hill a bit while going forward, to me that spells a definet float problem. While going forward gently pull the deck up a bit then push the deck back into float. The tractor will not "crab walk" unless the tires are actualy spining, wich I don't think will happen when mowing grass. I have'nt any time to check the arms on my tractor when in float yet but will do so as soon as possible (my wife works 2nd shift so I am Mr. Mom). Perhaps some one else does? Keep us posted, we will work this out.
PTRich

Charlie_Iliff · Apr 22, 2002

You describe a method for determining PERCENT slope, which is the way I've always seen road grades etc expressed. Throughout the threads here at TBN and on the Power Trac literature slopes are expressed in DEGREES, which has confused me a bit.
We can't have a Power Trac owner-operator "a bit confused" when complete confusion is so readily available. If you haven't already, grab a cuppa and read the following in flat mode: <A target="_blank" HREF=http://www.tractorbynet.com/cgi-bin/compact/showthreaded.pl?Cat=&Board=genbuy&Number=123879&page=&view=&sb=&o=&vc=1#Post123879>Thread link</A>
Then haul out some measuring tools and a calculator, or a laptop with mathcad, and you will be able to calculate the pucker factor to three decimal places.

MossRoad · Apr 22, 2002

I just figure the degrees is half of the percent and that's that. So, a 45% grade is 22.5 degrees, which is close to the limit that Kohler states for the 25HP Command series engines. I don't know what the Robbin engine is rated at. That is a tremendously steep slope, IMHO /w3tcompact/icons/smile.gif

PTRich · Apr 23, 2002

Reds:
Have not heard from you today, how did you make out?

Sedgewood · Apr 24, 2002

If you haven't already, grab a cuppa and read the following in flat mode:

Geez Charlie, that was a four cuppa read! I just couldn't put it down, except of course to go earn a PT loan payment. My bit of confusion came not from the calculation but from making sure in my investigations that folks were in fact using degrees and not what to me has always been percent to describe slope. Especially in trying to come to terms with Power Tracs 45 degree claim for the 1850. I can't imagine keeping my shorts dry on such a slope much less keeping from sliding into a fence as we well know can happen. I've had a couple of really close calls with my 484 at less than twenty degrees that should have killed me. Thanks for the link.

Reds · Apr 24, 2002

Thanks Charlie, just what I need in my life ... more confusion!

Reds · Apr 24, 2002

Okay ... i've just spent all morning reading different posts on TBN. So i really don't have the time to post at the moment ... but i will say that i took pictures ... measured the slope (in degrees) and cut the front hill!

Charlie_Iliff · Apr 24, 2002

John:
I agree about the 40 and 45 degree slopes for the 1845 and 1850. On those, to quote Daffy: "Not this little black duck!"
Last evening, I cut two weeks of growth on a very lush pasture. It is one of the areas I got the Power Trac for, because of some unscheduled rides down the hill on conventional tractors. (No one hurt, but no one talking about whether their shorts were damp ) I haven't measured the slope but will some day.
My PT 1845 has single turfs. One aspect of the front mower, of course, is that you are always driving on fresh cut, and therefore wet grass. On the steepest side cuts, I had trouble holding the hill, and actually tore some turf, turning the front uphill, which has the rear pushing downslope. I experimented a bit and found that I had been going too fast, of course. At slower speed, I could set up the crabwise traverse of the slope that you see on the Power Trac videos of the 1850 with duals on a 40 plus degree hill. The back end is a bit downhill, so all drive wheels hold the machine up the slope, and it moves a bit sideways.
Having played with it until the field was done, I reached two conclusions.
First: The PT 1845 is exactly what I want it to be. I can sidehill cut where I need to, in complete comfort, no pucker at all. It slides, but completely controllably. I can turn uphill or down at any time. If I go too fast, it's a bit less precise in placement, but poses no risk of a long slide or rollover.
Second: I may have chosen the wrong tires, and some day will change to the Michelin bar treads that Mark Chalkley has recommended. In the wet, the turfs probably do more damage than bar tires, either ags or R-4s. I am sure, however, that I don't need the duals. I'm not going any steeper than I already have tested. With dual bar tires, I wouldn't have slid at all, but the machine would be a lot wider and clumsier to make it better on a small percentage of use.
By the way, mine seems to run a bit hot with the rough mower. The needle doesn't peg, and it doesn't smell hot, but it's in the upper range. Have you seen that? Terry Estep, at PT, advised me to blow out the oil cooler exit on the left rear, which I haven't yet done. This Saturday is cleanup day.

Reds · Apr 24, 2002

Here's a view of the front hill showing the tractor from our driveway. The camera should be level since it was sitting on the BG&E box out front and the tractor is stopped where i lost contact with the ground to the point where i had to stop. I raised the mower, which lowered the wheel ... put the joystick back in float and moved forward. Front end starts sliding downhill and the wheel comes back off the ground.

The direction that i'm mowing is reverse from my previous problems. So left to right or right to left is no different. Now i didn't try upside down but i'm gonna assume that has no effect either!

Next i made a couple passes in reverse .... no problems except for a stiff neck. Back to forward ... raising the deck just to the point where you release the downward pressure off of the deck but the front mower wheels are still on the ground seems to solve the problem. Now i can go across the hill in forward without the front wheel lift or the sliding downhill.

So the question is ... is this normal? No one else seems to be complaining about front wheel lift.

The loader arms seem to put too much downward pressure on the mower deck which causes the front end to lose traction and slide downhill and raise the tractors front wheel. It seems as if the two pivioting wheels on the mower deck also are trying to steer the tractor downhill as they are pointed in the down hill direction due to the tractor sliding in that direction??? I'm guessing here!

Driveway picture is too big. I can repost this later after i resize it. Here's a view from the sidewalk in front of the house

I've used a tool that measures degrees. It can be used to truss angles i believe. Anyway ... i mounted to the tractor and it read 20 degrees.

MossRoad · Apr 24, 2002

That is a beautiful picture!

I've used a tool that measures degrees. It can be used to truss angles i believe. Anyway ... i mounted to the tractor and it read 20 degrees

Is that the steepest part? Looks like very thick, healthy turf. Glad you figured a way to get around it for now. It helps all of us out.

PTRich · Apr 24, 2002

Reds:
There should not be any down pressure from the arms, call power trac and tell them you have down pressure when you are in float. Love the driveway, I have a long one and plan to put grass on both sides like yours but I need material so it is on hold.
PTRich

Reds · Apr 25, 2002

Thanks MR ... the grass is pretty nice out front and pretty horrible out back.

Heres the picture i was trying to post earlier. It shows the angle better.

I think there are a couple places on this hill that are steeper ... if you go by feeling. Especially down in the drainage ditch. The protractor read between 20-22 degrees. So based upon your earlier comments ... that a 40 percent grade??

I can't take credit for the work around ... it was someone from TBN that suggested raising the deck. I believe it is i that should thank you guys for taking the time to think about my problems and answer my questions. So ... thank you everyone!!!

Reds · Apr 25, 2002

Thanks PTRich.

Is there a break in period with these tractors where maybe the hydrolics should loosin up over a period of time?

Does anyone think that the problem is the grade of the hill or is the tractor designed to handle this stuff? I haven't noticed down pressure on flat ground just on the slope I'll have to pay more attention next time.

marrt · Apr 25, 2002

Reds, I visited the PT factory this week (more on that later). While talking to the PT folks, I asked about your problem. As I began to describe the problem, the person I was speaking with finished my sentence with “and the front tire on the upper side will begin to spin.” Seems PT is well aware of this behavior and it is considered normal. I was told that when it occurs, one should simply “bump” the hydraulics to apply lift pressure on the deck, which puts more weight on the front tire to get traction again (as described previously in this thread). Once one is past the area causing the problem, simply put the lift back into float position and keep trucking.

Anyway, the key take-away from my perspective is that this behavior is normal and is a known side effect of the PT design. While somewhat annoying, this behavior is offset by all the other positives of the PT design.

bryce · Apr 26, 2002

STEEP!!! Hang a plumb bob from the ROPS and measure it on the flat and on the grade. This will give a very close slope measurement. Do you have a PT425? Why did you get the 48" mower as opposed to the 60" mower? How does the speed compare with a regular garden tractor? Does the PT bounce a lot when going fast on ground that has little bumps, like a lawn? When off the lawn and onto dirt, how much does it bounce? Does yours have enough power to mow tall grass, or does it bog down? How tall is the machine? Rober6t

Reds · Apr 29, 2002

Thanks marrt. Its interesting that when you talked to them this was considered normal behavior, but when i talked to them earlier they acted somewhat surprised that the wheel would lift off of the ground. What you describe is exactly the solution to the problem that i have come to ... with the help of others. It still seems to me that more weight in the front end of this machine would solve this minor problem. And yes while annoying, the added abilities of this machine over my garden tractor definitely "outweigh" this annoyance.

Reds · Apr 29, 2002

I used a protractor attached to my PT422 with the 60" mowing deck and the slope measured 20 degrees. Which, if i understand previous posts here, means a 40 percent grade. I never had any problems with my GT when cutting this hill. Now this was my first tractor/hill cutting experience, so this is all i have to compare with. My previous tractor was a 25hp Simplicity Legacy with a 60" deck and as far as quality of cut, riding comfort, power while cutting tall grass, there is no comparison. Cutting grass is what this machine was designed for and it wins hands down ... imho. Speed for the two is the same at 8mph, the PT422 is definitely noisier engine wise and mowerdeck wise. The Legacy deck was suspended from the frame while the PT deck rides on the ground. The Legacy cutting radius was much tighter than the PT422. Both tractors have enough bounce to them that when moving fast across bumpy ground you'll slow down. The PT is different beacuse the front moves independently of the rear which you will feel on bumpy ground.
On the other hand the PT422 makes an ok Simplicity Legacy. The Simplicity Legacy would make a very poor PT422.

MossRoad · Apr 29, 2002

The Simplicities have a great cut, don't they. Nice striping pattern like a ball park.

Reds · May 1, 2002

Yes they do. My neighbor, who upon seeing the PT for the first time gave me the ugliest tractor award, doesn't think i'll be happy without the stripes.

I was very happy when i moved a weeks worth of mulch in a few hours, when i planted three trees in a couple hours ... without swinging a pick.