Contemplating building a riding mower. Need help with design ideas.

   / Contemplating building a riding mower. Need help with design ideas. #1  

oughtsix

Bronze Member
Joined
Mar 16, 2009
Messages
91
Location
Redmond, Oregon
Tractor
'58 Fordson New major, BCS 735 & 715
I have a 20 year old John Deere F725 mower that I use to mow the 3 acres of lawn on my 5 acre property. It does a beautiful job and is much faster than my old mid deck mower BUT I spend almost as much time keeping it running as I do mowing with it.

After the shell shock on the price of new mowers and their apparent complete lack of quality I have decided to build my own mower to save money (Ya Right!!!)

What I have collected so far in my parts arsenal is:
1) A brand new tandem variable volume hydraulic pump aka skidsteer.
2) A set of 4 identically matched 7 cu in wheel motors.
3) A set of two matched 15 cu in wheel motors.
4) An 84 Toyota Corolla with 86K miles, a good engine, 4 new tires, a new clutch and a smashed rear end.

My goals are:
1) Fast, efficient mowing of the lawn.
2) Simple easy to maintain design.
3) I would like to be able to use this rig for other purposes around my property. Including stuff like digging trenches for pvc pipe (irrigation) spreading bark dust, moving the plethora of 12" and under sized rocks, Rototilling , some dirt moving and landscaping.
4) I would also like to make a quick attach belt drive engine PTO for accessories like a york compressor for mobile compressed air, a belt drive pressure washer pump and a generator head. (My biggest need for the generator is to power my well pump during very occasional extended power outages.)
5) A front end loader for spreading bark and moving dirt. My thought is to make my contraption with a front end loader very similar in design to a skid steer with the arms attached/pivoting at the back of the unit. I would make it so I could remove the bucket and I would mount the hydraulic drive mower deck in its place. The mower deck design is it's whole topic on it's own.

So my plan is to use the 1.4l Toyota engine as a sort of universal power plant. I am not concerned about the fuel consumption of any of the operations because none of them are going to see enough hours of use to make that much difference.

My first design decision is how to steer this contraption. I have already decided on hydraulic drive. I have considered several options and they all have their pros and cons.
A) Rear wheel steering, 2wd. This is what my F725 has and it is very maneuverable. Con: Without power to the rear wheels a FEL would be practically useless.
B) Rear wheel steering, 4wd. Con: I don't know how I would work out the differential action between all 4 wheels being on a different turning circle.
C) Front wheel steering, rear wheel drive. Classic two wheel drive tractor configuration. Con: I would be giving up a lot in manuverability while mowing.
D) 4 wheel synchronized steering, 4wd. This has some appeal since the two outside wheels and the two inside wheels are on the same turning circle they could be driven at the same speed. i.e. one variable displacement pump for the left wheels and the other for the right. Con: It would be difficult to synchronize the inside wheel speed /outside wheel speed with the angle of the wheels mechanically. I also wonder if I would be giving up some maneuverability while mowing.
E) Skid steer. Tear up the lawn!
F) Classic zero steer ZTR with rear casters. From everything I read this is the best setup for mowing providing the most maneuverability and best mowing speed when there are obstacles (my yard). I also have everything I need for this hydraulically already. Con: A FEL load would be practically useless with no power to the rear wheels.
G) Articulated steering aka CadTrac. This has some apeal and would be very simular in functionality and engineering to C) 4 wheel syncronized steering.
H) Hybrid Zero Steer ZTR - Skid Steer. This is currently at the top of my list. I would make a classic ZTR with one rear caster then make two additional Drive wheels that could be raised / lowered to accomplish skid steer capabilities when using the front end loader (or fixed rear wheels and raise / lower the caster). This seems like the most versatile option giving me mowing maneuverability and dirt moving traction. I would leave provisions for a rear mounted back hoe. Con: trying to keep everything compact with the caster / skid steer arrangement. Stability of a tricycle: My yard does not have a lot of hills and the one hill it does have is not very steep. I figure if the rear power wheels are not raised very high off the ground they will provide a bit of safety for catastrophic operator balance stupidity.
i) ZTR with front mounted mower deck and rear mounted loader. This would only require two powered wheels and they would provide enough traction when using the REL (Rear end loader). I liked the idea of the mower being on the Loader arms so I can use the loader hydraulics to raise / tilt the mower deck for transport and deck maintenance.

Any comments/thoughts would be appreciated.

Other thoughts: I have been thinking of a front mounted hydraulic powered rototiller mounted to the arms in place of the bucket / mower deck. Do you have to lift a rototiller when you are turning a corner when using a 3pt tiller on a regular tractor?

It would be nice to be able to keep the clutch on the Toyota engine so I can uncouple the hydraulics when starting the engine and when using one of the belt mounted accessories like the generator head. I haven't pulled the motor out of the car yet so I am concerned about how difficult it will be to mate the pump to the engine through the clutch.

My plan is to start by mounting the motor on a sled and figuring out how to mate the pump. Then I will build the frame of the tractor around the sled so the whole sled can be unbolted and removed for easier motor maintenance.

I got a great deal on the new tandem variable hydraulic pumps with one carvat.... I have know idea what there maximum displacement is. So it will be interest to see how fast the contraption will move. I figure I will be able to do some tuning to the maximum speed by varying the engine speed, the wheel size and the maximum deflection of the swash plates. I am guessing that because the tandem pump was made for a skidsteer it is probably going to be a higher maximum displacement unit than most ZTR pumps which will be pushing the 7cu in mower wheel motors pretty fast.

The tandem pump has provisions for stacking a standard hydraulic pump to the back of the tandem pump for powering accessories. My plan is to build a powered chassis first and then figure out the correct displacement for the accessory pump.

To drive all 4 wheels in skid steer mode I am thinking of running the wheel motors on the same side in series. This would be a lot less complex and less plumbing than running them in parallel using a flow divider. I am not sure I could run them in parallel in the closed loop mode the variable pump is made for without using a rotary flow divider on each side. I am not sure I can run the wheel motors in series? I think I can???

A skid steer / ZTR configuration would pretty much mean twin stick controls. I am not sure how I would control the hydraulic accessories efficiently except to mount the accessory controls to the sticks. Maybe electrically controlled accessory valves (expensive) and electrical push buttons on the sticks? Or try to rig a steering wheel with foot controlled speed and direction controls. (My F725 has separate forward and reverse pedals and I really like that configuration).

Uhhh... brakes. My wheel motors did not come with internal or external brakes.
 
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   / Contemplating building a riding mower. Need help with design ideas. #2  
Sounds like this is going to be a fun thread. I don't have any suggestions right now (you have that pretty well covered), but I'm sure there will be plenty from these guys as your project progresses.

Remember, the first 2 rules of TBN is: (1) Post Frequently and (2) Take lots of pics. :D:D

Oh, as for steering, I'm kinda of partial to atriculated. I have been gathering parts and drawing plans, hope to start on mine in the spring.

Mike
 
   / Contemplating building a riding mower. Need help with design ideas. #3  
I got bored one day and drew up plans to build myself a ZTR with diesel engine. I figured everything up and I could build it a lot cheaper (even with a new engine) than a comparable retail unit. I may even build it one day.:rolleyes:
 
   / Contemplating building a riding mower. Need help with design ideas. #4  
I've been going through a similar quandry lately. I want to put a FEL on a garden tractor, but I also want to have a forklift, but I also want to have a front deck near zero turn or true zero turn mower. (I currently have an F525, similar to your mower.) The conclusion that I have come to is that in terms of practicality, you need two machines. The zero turn mower just doesn't seem to mate well with any of the other ideas. The forklift and the FEL could be combined. In fact, forks could be put on the FEL. And then all the accessories would run off of it. The zero turn mower still stands on its own. I just can't find a really good way to incorporate it into the other machines.

Dave
 
   / Contemplating building a riding mower. Need help with design ideas. #5  
I have made my own tractor (several times now). Used two Kubota F2000 axles and HST (one from salvage yard). Articulated in middle, turns with hyd motor from the stock steering valve. 20 Hp diesel, all wheel drive all the time, with about 20 degree roll on rear axle. Really gentle on our sandy lawn because all wheels drive no slip, no skid.

Currently doing a redesign to final taking advantage of what I have learned. What I learned was that I wasn't smart enough to do it right he first two times.

Its an idea.
 

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   / Contemplating building a riding mower. Need help with design ideas. #6  
Bobcat used to offer a vertical mast attachment where you tok the arms off and had a forklift mast bolt to the front. Then they came out with a hydraulic caster wheel set up to pic the rear end up and use it like a spyder lift so it wouldnt mar up the yard. This was popular among sod farmers. Its an old attachment for the older machines. Theres also a few like that made in Italy that had real small wheels its a masons skid steer and it has the 5th wheel. I had a friend that had a large sod farm and before he passed away let me operate his wit hthe tail attachment. He left the regular loader arms on his and used it on his sod farm to keep from tearing it up. It was very handy and saved alot of hand work and wear when driving it across the land. I missed a chance on a good Case articulated trencher frame at a sale last weekend. It was stripped down and had a stump grinder head built on one end and the trencher on the other. All hydro drive. Would have made a great utility tractor.
 
   / Contemplating building a riding mower. Need help with design ideas. #7  
We have an articulated Husqvarna mower. Riders for Homeowners | Husqvarna Ride on Mowers

It swings the mower inwards because of the articulated steering, so you can mow around an 8 inch tree in one turn. The manoeverability is great, as well as the straight ahead steering stability. I have never used a zero turn mower, but i assume the articulated mower has better straight ahead steering stability, especially when you also want to use an angle snow blade in winter.
 
   / Contemplating building a riding mower. Need help with design ideas. #8  
Any new ideas on the build?I like the idea of articulated 4x4 with the attachments connected to the arms like a Bob Cat skid steer.
 
   / Contemplating building a riding mower. Need help with design ideas. #9  
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   / Contemplating building a riding mower. Need help with design ideas. #10  
If you don't want a ton of maintainance then you want to keep it simple. The old Houghes payloaders were 2wd with rear wheel steer. The large drivewheels where at the front and so when loading the bucket you had near 4x4 performance out of a 2wd tractor.
 

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