Slope Climbing Capabilities

TheYard · Mar 6, 2020

I have a small property (little over an acre), and I'm just looking for a machine that can basically substitute for muscle as I get older - lift, dig, carry etc. (e.g. wallstone, mulch, 2' deep trenches for wires, drainage, holes for shrubs in loam with lots of good sized rocks, turn the compost pile). I won't be needing it to mow - I'll get an inexpensive rider for that can handle the leaf volume that we have around here.

The property has slopes of up to 20%. I don't need to do a lot on those slopes, other than get up and down the slopes to the areas where most of the work will occur.

The PT machines themselves look really useful, but I did see a video the other day of a 425 with a brush mower seemingly struggling to get up a hill that's similar to what I'd be dealing with.

If I had a loader full of wall stone (or a trailer), would a 425 be able to pull it up a 20% slope? Or would I need something more powerful?

Any experiences you can share would be appreciated!

MossRoad · Mar 6, 2020

Welcome to the PowerTrac forum. :thumbsup:

A 20% slope is only an 11.3 degree angle. A PT425 with a bucket full of stone could go up that without issue. Pulling a trailer is a different story.

The reasons are these:
Going up hill, there's more weight on the rear tires. If you put a load of stone in the bucket and lift it off the ground even just an inch, that will transfer a lot of weight to the front tires, you'll get a lot better traction, and up the hill you'll go.

If you put a trailer on the rear vs a load of stone in the bucket, that would concentrate more weight on the rear of the machine and you'll lose even more traction on the front.

I've posted a few videos of my brush cutter going up hill, so maybe that's what you saw. A couple things to note if that's the case:

My PT425 is a 2001 model. The newer models have larger wheel motors so they are stronger on hills than my 19 year old machine.

When I'm pushing the brush cutter in float up a steeper grade, with the brush cutter in float, the brush cutter's weight is riding on it's own wheels and the PT425 is just pushing it. Eventually I'll start to loose traction on my machine in all 4 tires as the slope gets steeper. If I pull back on the joystick, taking it out of float, that take's the brush cutter off of it's own wheels and transfers its weight to the FEL arms on the PT425, effectively transferring the entire weight of the brush cutter and part of the FEL arms from the brush cutter to the PT425's front tires. It also takes some weight off the rear tires. What that does is concentrate several hundred pounds of force to the front tires for better traction. Then up the hill I go. Works quite well.

ernemats · Mar 6, 2020

I have a 22 year old 422 with lots of hills and it handles the slopes with no problem most of the time. If it is warm out and I have been working it hard then it struggles on the steep slopes if trying to mow up hill. Shutting the mower off helps. I often have a bucket full of dirt going up steep slopes with no problems, now with a trailer on behind with about 800 pounds of material in it it needs more power.

TheYard · Mar 6, 2020

This is all good information. I need to get down to the factory to try these out!

agjones · Mar 6, 2020

Always impressed with the slope capabilities of the 425,I noticed a significant boost in uphill work ability after adding ultraseal to the tires.

4570Man · Mar 6, 2020

A 20 percent slope is nothing. Even a regular tractor can handle that much and a machine like a PT or a Ventrac won’t have any trouble.

marrt · Mar 6, 2020

I would recommend you test the 425 before buying. In my experience, it's hard to estimate slopes accurately.

I have two 425's. One with the standard "new" wheel motors and one with larger wheel motors I added to improve performance on slopes. Others have added larger wheel motors too. I really don't see why PT doesn't offer this as an option. My large wheel motors are twice the displacement of the standard motors and I find this size to be perfect for my use. It will travel as fast as I'm comfortable going on "off road" terrain (i.e., with no suspension, the ride is too rough if I go faster). On pavement, it's a little slow but I'm rarely on smooth surfaces. For me, the standard wheel motors are way too fast. However, I can see how they'd be appropriate for many applications. It just depends on your conditions and intended use.

In case you don't know, smaller displacement wheel motors generally turn faster but with less torque, given the same flow. Larger wheel motors, like a larger hydraulic cylinder, take longer to "fill with fluid" but have much greater torque.

TheYard · Mar 6, 2020

marrt said:
I would recommend you test the 425 before buying. In my experience, it's hard to estimate slopes accurately.

I have two 425's. One with the standard "new" wheel motors and one with larger wheel motors I added to improve performance on slopes. Others have added larger wheel motors too. I really don't see why PT doesn't offer this as an option. My large wheel motors are twice the displacement of the standard motors and I find this size to be perfect for my use. It will travel as fast as I'm comfortable going on "off road" terrain (i.e., with no suspension, the ride is too rough if I go faster). On pavement, it's a little slow but I'm rarely on smooth surfaces. For me, the standard wheel motors are way too fast. However, I can see how they'd be appropriate for many applications. It just depends on your conditions and intended use.

In case you don't know, smaller displacement wheel motors generally turn faster but with less torque, given the same flow. Larger wheel motors, like a larger hydraulic cylinder, take longer to "fill with fluid" but have much greater torque.

Did you change out the wheel motors after old ones failed, or just changed them out to start? How much extra torque did you think you got?

marrt · Mar 6, 2020

TheYard said:
Did you change out the wheel motors after old ones failed, or just changed them out to start? How much extra torque did you think you got?

I changed them when the Subaru engine failed. At that time, I decided to rebuild the tractor. I also purchased a larger engine and new variable displacement pump (sent the old one for a rebuild...which, to my surprise at less than 400 hours, it needed). All this required quite a bit of fabrication, but I enjoy working on stuff. I also have an 1845 that I rebuilt. I bought all these tractors used (although, my first 425 was bought new from PT...I sold it to my neighbor).

The new wheel motors provide about 1.75x more torque. That said, the 425 is a great machine with the current wheel motors. I'd say it's main weakness is the relatively low amount of torque in can put to the ground. For example, a Kubota BX series will effortlessly spin it's tires, in low range, when trying to fill the bucket. That's because it has a mechanical transmission hooked to a variable displacement pump. PT's hook a variable displacement pump to wheel motors. The 425 will spin its tires some when pressed but it doesn't like it (i.e., you shouldn't do this every day if you want long service out of the pump). The BX series is great because it's two speed transmission provides a choice between speed and power. With the PT, it's more of a compromise. That said, the PT will run circles around the BX when doing bucket work once you learn how to maximize its capabilities (proper bucket technique is more critical with the PT). Keep in mind...with any hydraulic machine, the pump control is not a "gas pedal"...you get more torque by letting up on the pedal...at least until the motors stall or you generate enough pressure to activate the relief valves.

I'm not trying to dissuade you from a PT...obviously, I like them since I have three (I also have a Kubota L series tractor). For use as "muscle" as you get older (I'm 55) they are absolutely perfect in my opinion. Just yesterday, I used one to quickly grab a plate compactor and set it in the bed of my pickup. I commented to my dad about how neat these tractors are for stuff that would be a hassle otherwise. I've even been known to use one to take trash to the curb.

I ended up buying a second 425 because I took the first one to my Dad's house but missed it too much. Once you have one, you'll be amazed at the stuff you do that you've been putting off.

TheYard · Mar 7, 2020

marrt said:
I changed them when the Subaru engine failed. At that time, I decided to rebuild the tractor. I also purchased a larger engine and new variable displacement pump (sent the old one for a rebuild...which, to my surprise at less than 400 hours, it needed). All this required quite a bit of fabrication, but I enjoy working on stuff. I also have an 1845 that I rebuilt. I bought all these tractors used (although, my first 425 was bought new from PT...I sold it to my neighbor).

The new wheel motors provide about 1.75x more torque. That said, the 425 is a great machine with the current wheel motors. I'd say it's main weakness is the relatively low amount of torque in can put to the ground. For example, a Kubota BX series will effortlessly spin it's tires, in low range, when trying to fill the bucket. That's because it has a mechanical transmission hooked to a variable displacement pump. PT's hook a variable displacement pump to wheel motors. The 425 will spin its tires some when pressed but it doesn't like it (i.e., you shouldn't do this every day if you want long service out of the pump). The BX series is great because it's two speed transmission provides a choice between speed and power. With the PT, it's more of a compromise. That said, the PT will run circles around the BX when doing bucket work once you learn how to maximize its capabilities (proper bucket technique is more critical with the PT). Keep in mind...with any hydraulic machine, the pump control is not a "gas pedal"...you get more torque by letting up on the pedal...at least until the motors stall or you generate enough pressure to activate the relief valves.

I'm not trying to dissuade you from a PT...obviously, I like them since I have three (I also have a Kubota L series tractor). For use as "muscle" as you get older (I'm 55) they are absolutely perfect in my opinion. Just yesterday, I used one to quickly grab a plate compactor and set it in the bed of my pickup. I commented to my dad about how neat these tractors are for stuff that would be a hassle otherwise. I've even been known to use one to take trash to the curb. I ended up buying a second 425 because I took the first one to my Dad's house but missed it too much. Once you have one, you'll be amazed at the stuff you do that you've been putting off.

This is great info - thank you (and everyone) for all their guidance.

I have a lot of work in the yard to do. We are just embarking on some major renovations in and out - for example, I just had a crew come in and clear 30 oak trees, and I have a rental stump grinder sitting at the end of the driveway for a day of cleaning up stumps. Then there is going to be a lot of rock pulling (100 maybe > 200lbs), some excavation/regrading here and there, digging out smaller stumps (2-3"), building some dry laid retaining walls, building masonry steps, digging holes for plants, creating garden paths with wood chips - we had the tree guys leave some of the chips, digging trenches for drainage and electrical, digging footings for a new shed). Once all the construction is done, there will be maintenance (mowing, leaf collection, re-mulching beds)

It seems there are lots of ways to solve those problems - hire it all out, rent everything/diy, rent some/own some/diy. The first is a lot of $ around here, and it's time consuming to get bids, vet vendors etc.

I'm leaning towards rent some (like the chipper) and own some (like a tractor with an FEL). Funny you should mention Kubota - I'm thinking this is a showdown between and 1880 and a 425. They are in the same ballpark price wise with just the loader (considering shipping costs on the 425). And then after that, there's all sorts of pluses and minuses from warranty to serviceability to re-sale value.

I think in the end its going to come down to machine capability - in particular, whether I can find a grapple that can lift some of the boulders we have around here and help me place them in the walls.