I have wheel weights and my tires filled but on a smaller tractor. I can not say I really notice that much more traction but it did add some stability. By the way I had 175# rear wheel weights first then put 4 30# front suit case weights on later then last year put in 20 gallons of Blue Windshield Washer Fluid in each of my rears for 40 gallons total or about 320#.
Chris
Diamondpilot - can i ask how you filled those tires? is there an adaptor - i was thinking i'd have to take mine to a dealer - i'm adding a FEL
GPintheMitten - thanks for the mold idea - i was working out in my head what i'd do for a mold - i've got some 3/4" X 8" steel rings with a 4" donut hole, basically giant washers i was going to do similiar to you - use the giant washers for the backside of the concrete weights, weld some tubing to for guides or bushings for the bolts to pass thru and weld in some rebar - but the mold was worrying me - i've got a ton of different size plastic buckets
tks