Back in 2014 I did my own experiment balancing tires with a bunch of Air Soft Plastic BBs. I did it on a '92 Thunderbird I had, 6 ounces BBs in each tire, P225/60-16s. I was looking at notes, seems I was real happy. I know my Trike had the BBs too. It's the same idea as using liquid balance media.

My grandpa had a 1955 John Deere MT with tall rear tires, it was not a slow tractor when in 4th gear and that throttle was up to wide open on a hard surface road that run along side the farm, you did not dawdle on that road as there was a lake nearby one way and a lot of people used that road too fast, so when we were on the tractor pulling a piece of equipment or trailer coming back to the house, you threw that lever up after getting it going in high gear, and I loved to watch the mud or dirt slung way down the road. The rear tires were fluid filled but it never vibrated. Was running a good 40 mph and those tires had way more than a balancing load of liquid.

If I ever need to put another set of tires on my '77 F-150, I'm might just pour a quart of just 50/50 mix green antifreeze in each & call it done, it's "rubber friendly" and I'm told it works well too.

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But there is then a question as to repairing a flat. Might be OK, tires run on roads with dirt, grease, grime, bug guts, oil spills, smeared critter remains, tar, vehicle fluids from wrecks, you name it. Plugs work there. It's not like a tire is a sponge. A 50/50 mix of AF/water is at least as vicious as straight rainwater. Nothing about If one was repairing a tire with a "patch-plug" (after breaking the bead loose) that had a 50/50 mix antifreeze, just clean the rubber, degrease, scuff, apply the "patch-plug" with the vulcanizing glue (pull into place), pump it up, trim excess as normal.

Yeah, you guessed it, going to use the pint (or quart even) of 50/50 "trick" in my '77 anyway. Be cool watching the tire draw it up out of the cup.

A cheaper alternative would be using windshield washer fluid.

 

Yes, fluid will work on the same principle as balancing beads that many motorcyclists use. I haven't tried them and probably won't because I suspect they tend to work at higher speeds better than low speeds. I don't have an issue with weights. I thought water in tractor tires was used to add weight to the rear tires for better traction.

 

It is …. way more than needed to balance, but if the wheel & tire are spun up fast enough to create imbalance, the liquid will balance them. When the tractor is moving at low speed, the liquid stays in the lowest part. There's no force to carry the liquid over the top at low speed. Speed I up fast enough to cause an imbalance to show it's head, the liquid counteracts the heavy spots. It will self balance.

Imagine a tire & wheel, not balanced. Imagine it has a 2 ounce heavier spot at point A. Imagine there is a point B directly opposite. Every time that wheel rotates, the extra 2 ounces pull the tire and wheel in it's direction with a force decided by the arc, the speed as Point A is spinning as it is forced into this "arc". As it goes over the top of this spinning tire, it pulls the tire a little bit up, the faster the speed, the harder the pull, the greater the imbalance is felt. The tire and wheel jumps because it's a little lighter on the ground due to the pull.

Now, add in a few ounces of liquid or beads. When the same pull up is exerted each revolution at Point A, the "jerk" causes the excess liquid or beads to go to the far side, to Point B. This happens every revolution. The higher the speed, the greater the pull by the built in imbalance, the harder the liquid or beads is thrown into Point B. This happens constantly and the liquid or beads is free to move in reaction to every action of the unbalanced tire & wheel.

At rest, any liquid or beads drop to the bottom due to gravity. At very low speeds, you feel no imbalance as no force is being generated enough for you to feel it. As speed increases, the liquid or beads are constantly reacting to any force, even those you might not otherwise feel. At speed, the tire and wheel don't "bounce" as any start to bounce is instantly cancelled out by the free to move liquid or beads.

A potential problem with liquid or bead balance is that the force generated by the rotation is coaxial ... ie: in a plane perpendicular to the axis or wheel center ... so that if a tire has a wide flat inside floor under the tread like say a 50 series tire maybe, beads can find them selves on one side, where as a liquid is gonna be distributed smoothly across. The tire will be balanced as it would if balanced statically (like bubble balanced) but maybe not as if balanced dynamically (like spin balanced). My experience is any such effect is mild and smooths out rapidly at speed.

A benefit of liquid or bead balance is it reacts to a tire and wheel with a big mud ball inside and if enough liquid or beads is present, will counteract it and balance the mass at speed. Weights can't do that "on the fly".