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AKA Moses Lawnagan
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Discussion Starter #1
I've read several posts in various threads over the last few weeks, anything from "should I mow up and down, or across", to "my hydro gives up on steep hills". I don't suppose to offer any answers or recommendations here; it just got me thinking, so today, I went down to my steepest spot that I have to mow, with my tractor and a Johnson Angle Gauge, to see just how steep it really is.

I usually mow across this hill, mainly because there is a fence along the upper edge, and mowing across allows me to trim up to the fence. There is also a small bog and pond at the bottom of this hill, and should the brakes ever quit, mowing across will forestall ever having to dig the tractor out of the bog.

First picture shows the mower parked sideways on the steepest portion, with the angle gauge sitting on the front weight rack, which is level when sitting on level ground. The gauge reads 20 degrees (2nd picture). This equates to a 21% grade. Getting on and off the tractor, from either the uphill or downhill side, is a bit of a challenge, but the tractor doesn't budge. It weighs around 1300 pounds. When I did this with my GT235, which weighed about 550 lbs, it felt much less stable.

Now, with the tractor pointed uphill, (3rd picture) the angle gauge is sitting on the toolbox, which is level when the tractor is on flat ground. Here, the gauge is reading 22-1/2 degrees (4th picture), which equates to a 25% grade. This tractor will pull this grade in either 2WD or 4WD, although I sometime have to lock the differential in 2WD. That said, I always mow this area in 4WD due to the much, much improved braking of 4 wheels when facing downhill (a story for another post). My GT235 would not pull this hill with standard turf tires, I had to put ag tread on it and then it did fine. I also always mowed across with the 235, and always made my turns going uphill, because if it started sliding, putting on the brakes was futile (another story for another post). Plus, I was hanging off the uphill side of the seat like the "monkey" on a racing sidecar motorcycle anytime I was mowing with the 235.

This is more of a FYI than anything else, compare the pics to your own steepest place and see how they compare. If you have steeper places than this that are regularly mowed, I only have one question: how do you keep your cojones out of the way?
 

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AKA Moses Lawnagan
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Discussion Starter #2 (Edited)
Here's another view of the hill I mow, with a bit more perspective. The tractor is sitting in the same spot as the previous post.

I used to mow this hill with a Yanmar 1810D and a rear mower. I always faced downhill, and mowed backwards to the fence (uphill) and forwards downhill, always in 4WD. What a PITA that was. NO WAY would I have tried to mow across the hill with that tractor. The weight was a bit more than my 748, but the c/g had to be 2 feet higher, and it had no ROPS.
 

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Certified Technician
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I wouldnt mow any steeper than that, I mean that's pushing the envelope of a few things, mainly engine lubrication. I know on some engines, they say max engine tilt is 15* constant, 20* max for brief periods of time...

The thing is, mowing a hill, if it starts to tip, roll, or pitch to one side, there is not much you can do but ride it out and hope for the best.

We have a hill at work, it's steep, probably 40*, it's short though, maybe 6 feet long on a 4 foot rise.

Ive tried multiple mowers going up that little hill and so far the only one that came close was a 4wd Simplicity Prestige but even it was losing grip...
 

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Among the many drawings I have made for devises is a swing arm with a weight on the end of it. The swingarm would attach to the rear of the tractor and swing to the side of the tractor that is uphill. Go ahead and make one if you want but its one of my ideas too odd and possibly too dangerous in the hands of the average non-mechanical guy mowing his steep lawn. Its one of my ideas I will not manufacture. Another idea I came up with was a bunch of liquid tanks mounted on front, rear, sides of a tractor. Have an angle sensor control pumps to pump the fluid into the tank on the uphill side of the tractor. Not really a practical idea but I wrote it down anyway.
 

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I have a hill to mow, but not that bad!!! I would think about adding some wheel weights on it if you dont. Some weight low would help it be a little more stable. Also if the tires have a wide, and narrow setting, you would want them as wide as possable.
 

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First picture shows the mower parked sideways on the steepest portion, with the angle gauge sitting on the front weight rack, which is level when sitting on level ground. The gauge reads 20 degrees (2nd picture). This equates to a 21% grade. Getting on and off the tractor, from either the uphill or downhill side, is a bit of a challenge, but the tractor doesn't budge. It weighs around 1300 pounds. When I did this with my GT235, which weighed about 550 lbs, it felt much less stable.

Now, with the tractor pointed uphill, (3rd picture) the angle gauge is sitting on the toolbox, which is level when the tractor is on flat ground. Here, the gauge is reading 22-1/2 degrees (4th picture), which equates to a 25% grade.
Good discussion - this reminds me of the tractor pix of the guy with his wife sitting on the tractor fender for a counterbalance because it only has one front wheel and the other one is busted off. I wouldn't like to bet my life or limbs against a 1300 lb tractor!

One thing I noticed is that the calculations of % slope are incorrect for the degree angles shown. Degrees display angles of a circle, while % is a calculation of rise/run. They do not equate directly and you must use trig to solve - or google up a handy dandy conversion table on the web. 20 degrees = 36%, and 22-1/2 degrees = 43%. I just mention this in case someone is looking at their owner's manual and doing the mental math about how steep a % their 4x4 mountain goat LT can handle.

Whether or not the tractor tips depends on the center of gravity of the mower plus the operator. Overall weight doesn't fix the problem - I have seen D-8 cats roll over. Things like bumps in the turf can easily shift the center beyond the tipover point and over you go. If it's hard to get on and off on that hillside, it will be even harder to "jump clear" with a tractor chasing you into the pond.
 

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Good point on the conversion from degrees to percent. One needs to keep in mind that the front axle beam centre pivots so its essentially a tricycle. Don't look to front wheel stance as adding any sort of stability cuz it doesn't. Loaded tires would do the most for adding stability cuz of the lower centre of gravity.
 

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AKA Moses Lawnagan
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Discussion Starter #10
Thanks for the correction on my math. I was converting based on a vertical line being 100% slope, horizontal being 0%. A 45 degree angle would then be 50% slope, and 22.5 degree would be 25%. I didn't consider slope being the same as grade, in which the percentage is the measure of vertical rise in feet per 100 feet horizontal run.

Red, you mentioned the limit of angle that the engine can get adequate lubrication. That is constantly on my mind whenever I'm on that hill. I certainly make sure my oil level isn't low, regardless of how steep a bank I'm mowing, do you think I truly run a risk of uncovering the oil pickup? The other two machines I have used, one was another Yanmar diesel, it was the same displacement, but a slower running engine and had a deeper sump with greater oil capacity, and the other is a vertical shaft B&S. In over thirteen years of mowing this hill, I haven't developed any engine problems with any of those engines, or had any indication of oil starvation.

The 748 feels very solid going across the hill. It is not smooth by any means, but I don't find it trying to slide sideways when I hit a bump. The GT235 on the other hand, will sometimes sort of 'drift' the rear end down the hill on a bump, but not so much I felt like it would slide all the way around. The old 1810D never went across the hill, I just didn't feel like it would without tipping over.

I only mow this hill about 4 or 5 times during the summer, and never when the grass is wet. I don't go there with the tractor for much else.

One of the aforementioned "stories for another post" was back in Feb. I had my 4-wheeled wagon behind the 748 and it was maybe 1/4 full of firewood and I was going down the hill to finish loading it. I had forgotten to put the tractor in 4WD, and when I started to slow, the rear tires lost grip. Well, as you know, putting on the brakes is a lost cause. I went bouncing down the hill, only had about 20 feet to go, and the front tires stopped about a foot shy of the edge of the pond. Looking back up the hill, those big HDAP's had really tried to hang on, they'd pulled up the grass in two big skid marks down the hill. I thought I was pretty luck I didn't get to try out my winch.
 

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This is more of a FYI than anything else, compare the pics to your own steepest place and see how they compare. If you have steeper places than this that are regularly mowed, I only have one question: how do you keep your cojones out of the way?
Raise the angle up 10deg and watch your pucker factor go WAY up.I have a tilt meter on my tractor that goes to 25 deg and I peg it mowing sideways on the hill,but it's very uncomfortable to be sure.I have to finish it mowing up and down as the steep part is 30-32deg.Some parts the Hydro will stall out so it's downhill only,using the 4-wheel braking.A real thrill to be sure.

Here's a pic of a cheap and easy slope finder using a piece of plywood,a protractor,and a small nail.

Another poster brought up a good point-lubrication.I only recently found out,by perusing the Kohler website,the CH20 in my tractor with pressurized lube is only good for 25deg.I've been using this for 3 years on 30deg slopes.I use Mobil 1 Synthetic.Hope I'm not trashing the engine.It uses no oil and seems fine.
 

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I use the cheek-o-meter to mesure slope.:thThumbsU my drive is a 1/2 cheek,but my road bank is a cheek and a1/2!!!:Stop: :sidelaugh :sidelaugh
 
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