I thought I do not need them while using my snowblower on my lawn tractor as my 200 pounds of weight should've done the trick for traction. I was wrong! Tractor was spinning tires (even with chains on). As soon as I've added these - no more spinning - just awesome grip. I subtracted one star only because it is not very easy to put them on and off. Sears has a version with quick attach which is available only for garden tractors I believe. Very good product !
Craftsman 30 lb. Wheel Weights is recommended by aristokratika