Box Blade Sizing for Kubota L3901

[deezler]

^ this. Diff lock is only meant for rare circumstances when traction is really lacking. If you need it constantly, you are asking too much of your machine. With enough weight/ballast, operating at higher rpm in 4wd, you should have plenty of traction already. I basically never use the diff lock on my Kioti.

 

[John_Mc]

Research first. Pound-for-pound counterbalance on the Three Point Hitch is much more effective than liquid filled tires due to leverage, for FEL work.

I use both filled rear tires and an implement on the back of my tractor, and need every bit of it. Running a rear implement alone on the back was not enough for loader work (unless I put my brush hog on, but that was really inconvenient for maneuvering while doing loader work).

When using the box blade, the weight of the blade is important for getting it to dig in, but useless for added traction, since the weight of the blade is supported by the ground when doing any real box blade work.

 

[John_Mc]

My New Holland has a lever to depress to get lock in. It's a pain in the ass, as it unlocks when torque is taken away from wheels. I find I'm just leaving my heel on it, which isn't comfortable at all...

Your NH Diff Lock is working as it is supposed to. You are supposed to keep your foot on the diff lock pedal for as long as you want the diff lock engaged.

You may want to read a little on the diff lock in the owners manual of your tractor. There’s a high probability that it says to not drive around with your foot continuously pressing on the diff lock pedal.

From my NH TC33D Owner's manual (basically the same tractor as @Mtsoxfan 's NH TC29D:

"To operate the differential lock, depress and hold the pedal down until the lock is positively engaged. ... Release the pedal to disengage the lock.

NOTE: In some instances the lock may remain engaged after the pedal is released." (The emphasis is in the manual, I did not add it.)

 

[big bubba]

I have never heard of a limited slip differential in a tractor. I suspect they may exist in some more exotic application, but not in regular compact tractors.
All of the L series Kubota tractors I am familiar with have manual locking differentials.

correct. LmSlip ft differentials (at least on K tractors) occur on M7040 & above utility models. on lesser models & compacts, one gets creative on traction applications as illustrated on above posts. all good advice, regards

 

[Mtsoxfan]

I agree with you on how it works. I still think its a pain in the ass using it.

 

[ning]

A 3901 probably has the guts to pull a 72" box blade. Plenty of power, but the tractor is a little light. Loaded tires would help. Keeping your FEL bucket loaded with a scoop of dirt helps also.

I had a 72" box blade on my Cub Cadet 7305 (30 HP) and it was a little too big. Very easy to anchor it with roots underground, or an overflowing load of soil, and get the tractor stuck. Had to raise the box blade up a lot to keep moving.

I realize the scoop of dirt increases the weight of the entire unit, but is it actually going to help rear wheel traction (assuming it's kept in front of the front wheels, of course)?

 

[deezler]

No, a scoop of dirt obviously helps increase front wheel traction more directly. But I've also found that having that extra 700-1000 lbs of mass moving along on the tractor gives you a lot more momentum to "bust" the box blade rippers through roots, rocks, and keep the full load of soil in the box pulling along. I've never found that a full front bucket unloads my rear tires enough to lose traction on them. It just gives you more grunt overall, and helps transport twice as much material if that's applicable for your situation.

 

[S854]

…I'm new to dirt work…

Full disclosure: My BB tractor is a Kioti CK2610… HST, 25 HP, R14 loaded tires (rear)… obviously “smaller“ than your L3901…

I have yet to experience a situation where my 6’ BB resistance overcomes the available traction/power of the Tractor… I use low range, PTO engine speed and 4WD until I get my 1/4 mile-long drive (clay and shale) close to where I want it… I can then use mid-range to add the finishing touches…

On another note, if you don’t already have them, get hydraulic cylinders to replace your 3-point top-link and side-link… When I went from my Massey to my new Kioti, I had the dealer install the cylinders… BIG DIFFERENCE in not only ease of operation the BB but also getting the angle of the BB exactly where you need it..

 

[John_Mc]

On another note, if you don’t already have them, get hydraulic cylinders to replace your 3-point top-link and side-link

That's known as a "Top N Tilt" kit. You can find numerous threads on them here on TBN. Best to use a set up with double piloted check valves on the cylinder (my set up does not have that, and I've always wished I had know about that back when I was setting this up.)

 

[rScotty]

You can probably borrow a box blade to see what size you want. I'd guess for the 35 hp size a 5 feet wide for soil with clay, rocks, or roots, versus six feet wide if what you have is sandy dirt. Box blades are pretty much indestructible, so no need to get a new one. Used basic box blades with one ripper per foot are just about the cheapest implement out there. Rent or borrow to see what you need.

Whether a box blade is the right tool for you depends mostly on the type of ground you are working. My friends in flat ag country use theirs a lot. But my mountain side property is gravel, creek, and sand mountain side with rocks, pines, and roots. In spite of having three old box blades, I still haven't found one that works well on uneven sloped areas like that.

Your manual top and side link adjustments will get you by well enough to see if it's the tool you want.

If a borrowed/rented box blade works well in your application then you can look at the fancy ones and also at hydraulic top and tilt for the 3pt. That combo will give the bank book a workout. The roll over units by Danhouser are really nice. Also, some standard box blades have more adjustment trickery on the rippers than others - so check that out. On flat sand rippers can be set and forget....but mine require constant attention. Another thing to look for is that some box blades also have a handy reversed cutting edge that flips down on the back so you can smooth in both forward and reverse.

Finally, at least half the box blades you see will have some sort of homemade frame on top so that the user can pile rocks, weights, sandbags or tools on it to increase the weight. Keep that in mind when buying.

The alternate is to add a different tool to the FEL. Since box blades don't work all that well on our land I usually end up just using the FEL to reshape something the size of a side or backyard - using a toothed or rock bucket to loosen it up and a regular bucket to smooth and shape it. Back dragging is the trick with the FEL.

rScotty

 

[old and tired]

Not going to recommend anything to you... Just letting you know what I use. My L2800 HST and a 72" box blade works very well for me. I've flatten the sides of hill to make a flat spot that campers stay on and dug a new road down to the creek with mine. Moving material from the high side, down to the low side... to make a flat road. We have mostly dirt with a few rocks thrown in for fun

 

[Sid Post]

The Kubota L-series tractors are lightweight for engine size. My recommendation is to buy the smallest box blade or land plane you can so you don't overwhelm the tractor.

I run loaded tires in my L-4600 and I find it doesn't have enough weight to pull as much as the engine supports. I will spin the tires before I bog the engine. YMMV

 

[MF243RedTop]

6'. Cover the width of the tires plus an inch or two extra on each side. I dunno the width of a 3901 (what tires?) but if a 66" box blade covered it well, that would give you more ripping and pulling power.

Exactly the right advice .. strap more weight to the box if it's not digging to your expectations...and or add more weight/loaf rear tires if it won't pull it .

 

[BadgerCheese]

I'm running a Land Pride BB3584 which is 84" wide. It's a touch wider than my wheel base, and it pulls a LOT of material. The weight is 853lbs, so there's no nudging it into place to hitch it up, but it makes an awesome counter weight to the FEL. At 45 hp it's at the upper end, size wise, for my tractor. But when you set it down to dig in, it digs. I've only had to put the tractor in FWD or use the differential lock a couple of times pulling a full box up hill.

For the saying so, the rear tires are filled.

 

[mo1]

Ag tires on front and rear, 4 wheel drive and diff lock available as well.
I should also mention that it's an HST.
Wheel base according to tractor data is 63.3 inches, but I haven't measured mine.

I would say a 5' box blade would be a better choice than a 6' box blade. That would still be wider than your tractor as you noted the width is 55". I had a little Massey-Ferguson tractor in the past that was very close in physical size and dry weight to your Kubota, and it was also an MFWD unit on ag tires. It also had a loader on it which added a more weight too. The ag tires were not fluid filled. The 6' box blade I used with it was really too much for that tractor, it would lose traction and spin the wheels if the box blade got somewhere between 1/3 and 1/2 full of gravel on a dead flat driveway. Adding fluid to the tires would have helped some, but I somehow doubt that it would have made enough difference in traction to let it get the box good and full. I'd suspect that another 1/2 to 3/4 ton or so would probably be needed to get enough traction to pull it well.