john_bud said:
gemini5362 is just about 180 degrees off of my opinion on weights to counter the FEL load. My experience is that inadequate weight is dangerous. Makes it much easier to flip the tractor over. Makes you lose traction and makes the load on the front axle higher.
Some have differing opinions, but I feel strongly that all FEL equiped tractors (except for dedicated mowing machines) need to have filled rear tires and have 3pt ballast.
The way to tell if you are picking up something too heavy is to have the relief valve activate. That is a built in safety device that re-directs hydraulic flow away from the FEL and back to the tank. The relief is engineered to do just that and for that reason. If you pick up something and the tail end lifts - you are in very dire danger. And not just at that time, every time you use the FEL. Just because the tire didn't lift, doesn't mean it isn't about to lift or worse flip you over when you hit a bump or turn the wheel. Dangerous, very dangerous. Extremely dangerous. Dynamic loads are higher than static loads, so hitting a rock while turning on an un-ballasted tractor can flip it quick, where a ballasted tractor isn't impacted.
Always, filled rear tires and a 3pt implement or dedicated 3pt weight on all FEL tractors. Always. I like to see wheel fill, wheel weights and 3pt ballast all total to equal to 100-150% of the FEL lift capacity
Others will chime in with other opinions, so it's up to you to determine which opinion is most helpful. After all, WE are all proud of our opinions.
OK, I'm an "OTHER" chiming in. It is with great trepidation and feelings of angst that I break out of a long established pattern of virtually always agreeing with gemini (sorry Thomas) and essentially agree with John.
You can not safely accomplish all that much with an FEL on a modern powerful CUT because the little tykes are so abundantly endowed in the hydraulic department and are so small (short and light) unless you use added weight.
Loads that are well within the capability of the tractor and its FEL to safely handle with regards to hydraulics and steel structure as well as axles, bearings, and all associated load bearing stuff will in fact virtually always cause an unweighted CUT to have the rear wheels go airborne. If the rear wheels do not go airborne they may still get so light that the least little surface irregularity will cause them to bounce up leaving you unstable and unable to steer properly. Trying to tractor while doing a reverse wheelie is NOT RECOMMENDED.
MY Kubota's instruction manual goes into liquid tire fill in detail and then mentions except the cab model which may NOT use liquid fill (that is yet another small romance novel.) I have the maximum number of (Kubota supplied) cast iron wheel weights Kubota recommends (3 on each side.) This helps with traction and for doing FEL work. Still the little Kubota Grand L4610HSTC has much more FEL capability (Both strength of structure of the tractor, attachment points, FEL itself and bucket, and the hydraulics than can be safely used with only the wheel weights.
I can do much more work, safely, with some rear ballast. I can use my brush hog or my box blade as ballast to good effect. The brush hog limits maneuverability, especially in tight quarters so th;e box blade is the current counterweight of choice. I have a carryall that I have not used yet which will be tried out as an easily attached/detached counterweight with a weight secured to it. The weight will be a drum of rocks or barrel of water. Alternatively, I may build a 3PH counterweight as others have chronicled on this site.
My tractor is NOT too strong for its own good. It suffers the curse of all good CUT's, it is a lot of capability in a small package and being small it is short (low leverage to counterbalance FEL loads) and not extremely heavy ( a good thing part of the time) so at times its weight and balance needs to be intentionally and with cautious forethought, adjusted. Adding a counterweight farther back (than the tires) gets the balance job done with significantly less total weight added for the effect achieved (leverage.)
Considering convenience, some folks have their tires filled all the time and that is convenient for them (maybe) but I like the ability to easily and conveniently go light if I choose and liquid fill does not support that contention but counterweights do. I could, if so inclined, remove and replace my bolt on wheel weights with a lot less fuss than emptying and refilling tires with liquid.
Examples of common usage:
I have a bale spear for the FEL. Round bales often weigh over 1000 lbs and must be transported through whatever terrain in whatever weather as my stock MUST BE FED. I can not safely do that with no added weight. Depending on the bale I may lift the rear tires into the air instead of the bale and even if I can lift the bale I may not have reliable steering with the rear wheels sort of just lightly skimming the ground. Running around with 1000 lbs on the spike is trivial with counterweight.
Hauling a couple hundred T-posts out intp the pasture to support a fencing job: Same story.
Moving large rocks with the FEL: Same story.
Moving anything heavy with the FEL mounted pallet forks (rated for 1300 lbs due to being long when the short forks are rated for more by Kubota attesting to the factory approved lift capability)
Why have forks SAFELY capable of 1300 or1500lbs if you can't pick up that much and keep the rear wheels on the ground or on the ground with enough contact pressure to provide safety and steering?
I stipulate that gemini has a larger more powerful tractor in his Montana than my Kubota and can safely carry, with no counterweight, more than I can with no counterweight and maybe enough to satisfy him BUT I assert that his tractor will safely carry significantly more by FEL with added counterweight without exceeding any load restrictions of the maker, common sense, or practicality.
This doesn't make gemini wrong, more likely conservative and possibly just not fully informed. It is his tractor and he can use it any way he wants, even if it is perhaps in a much more limited manner than is still safe or allowed by specifications.
Sorry John but I have to disagree with the liquid fill for tractors that are specifically prohibited from having it such as my Kubota. I know that is heresy in some quarters but before you start gathering kindling for a cleansing fire in which to burn me at the stake, consider there are usually exceptions to rules, especially rules that people make up with limited exposure to contrary information.
Pat
As far as any new toys for my new 
