gpreuss
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Equipment
L3200DT w/FEL, K650 Backhoe, 5' Rotary, 40" Howard Rotavator, 6' Rhino blade
I read L3800’s thread about tire size on the L3800 - 4 ply rear and 8 ply front - and Bluegill’s response - they have to be heavier to handle the FEL. The topic had entered into my decision to go for R4 tires when I bought. I think we should all slow down a bit and think this through... We all want to go home every night in one piece.
When you have a loader putting the weight out in front of the tractor, the front axle and tires become the fulcrum or pivot of an effective teeter-tawter. If you put a thousand pounds out in front of the tractor, it is trying to pick up the rear end by the same amount. But, the weight on the front axle bears twice the load! If you have two kids on that teeter-tawter and decide to pick it up, you are taking the weight of both.
When we look at the tractor, we don’t think about it all that much. The FEL frame on the L3200/3800 weighs 860 lbs. The QA bucket is 300lbs. When you put them together, you have 1160lbs, with a CG about 3 feet in front of the axle. That means the front end is actually over a thousand pounds heavier, and the rear axle is about 600 lbs lighter (it has a longer lever) than a bare tractor. The front axle is carrying about a ton more than usual.
The other day I put 40 30lb concrete slabs in the FEL, about 2’ off the ground. I did it without thinking, and without anything on the back. Normally I have something on the back, that day I was just dumb. Yes, the rear tires are filled, about 400lbs each. I was facing uphill a bit. When I let off the brakes I immediately started backwards. I jammed the brakes back on, but couldn’t get it stopped for about 15-20 feet!! BAD!
So we take the initial 1160lbs and add 1200, giving me almost 2400lbs, with a CG more like 4 feet in front of the axle. That same 2400lbs is trying to pick up the rear end, about a foot in front of the rear axle. The math doesn’t lie - you ain’t got much weight left for traction!
There is one other thing to consider. In that real-world example, I put about 4800 lbs extra weight on the front axle, or about 2400lbs on each tire. The R4’s say they are good for 2060 lbs a tire, 6 ply R1’s (I couldn’t find a listing for 8 ply on the internet) are good for 1100lbs.
Makes you think.
Keep plenty of air in those tires. If you pick up a load and they really skush down, put in more air, and/or reconsider the load. And KEEP plenty of ballast on the back - you never know when you'll load yourself up.
After saying all of that, I did a lot of FEL work on my old L185DT. It had a size or two smaller R1 tire on the front end - I don’t know the ply count. On a couple of occasions I flattened the front tires with a load, and went and got the portable air tank and brought them up to about 40psi, and carried on my way. Never had a problem. Maybe too dumb to know better.
Now that I’m old and wise, I thought this all out, and wondered about why Kubota would sell a tractor with front tires that seemed so out of sync with anticipated load. So I bought the R4’s.
And then loaded 1200 lbs of brick, with nothing on the rear end but beet juice in the tires.
Work safe, and come home whole.
When you have a loader putting the weight out in front of the tractor, the front axle and tires become the fulcrum or pivot of an effective teeter-tawter. If you put a thousand pounds out in front of the tractor, it is trying to pick up the rear end by the same amount. But, the weight on the front axle bears twice the load! If you have two kids on that teeter-tawter and decide to pick it up, you are taking the weight of both.
When we look at the tractor, we don’t think about it all that much. The FEL frame on the L3200/3800 weighs 860 lbs. The QA bucket is 300lbs. When you put them together, you have 1160lbs, with a CG about 3 feet in front of the axle. That means the front end is actually over a thousand pounds heavier, and the rear axle is about 600 lbs lighter (it has a longer lever) than a bare tractor. The front axle is carrying about a ton more than usual.
The other day I put 40 30lb concrete slabs in the FEL, about 2’ off the ground. I did it without thinking, and without anything on the back. Normally I have something on the back, that day I was just dumb. Yes, the rear tires are filled, about 400lbs each. I was facing uphill a bit. When I let off the brakes I immediately started backwards. I jammed the brakes back on, but couldn’t get it stopped for about 15-20 feet!! BAD!
So we take the initial 1160lbs and add 1200, giving me almost 2400lbs, with a CG more like 4 feet in front of the axle. That same 2400lbs is trying to pick up the rear end, about a foot in front of the rear axle. The math doesn’t lie - you ain’t got much weight left for traction!
There is one other thing to consider. In that real-world example, I put about 4800 lbs extra weight on the front axle, or about 2400lbs on each tire. The R4’s say they are good for 2060 lbs a tire, 6 ply R1’s (I couldn’t find a listing for 8 ply on the internet) are good for 1100lbs.
Makes you think.
Keep plenty of air in those tires. If you pick up a load and they really skush down, put in more air, and/or reconsider the load. And KEEP plenty of ballast on the back - you never know when you'll load yourself up.
After saying all of that, I did a lot of FEL work on my old L185DT. It had a size or two smaller R1 tire on the front end - I don’t know the ply count. On a couple of occasions I flattened the front tires with a load, and went and got the portable air tank and brought them up to about 40psi, and carried on my way. Never had a problem. Maybe too dumb to know better.
Now that I’m old and wise, I thought this all out, and wondered about why Kubota would sell a tractor with front tires that seemed so out of sync with anticipated load. So I bought the R4’s.
And then loaded 1200 lbs of brick, with nothing on the rear end but beet juice in the tires.
Work safe, and come home whole.
