I cant say for sure that they are the lightest but BFG KO2's are pretty light and so are Duratrac's. Grip isn't as good as Mud Terrain IMO but I'm happy with my KO2's.

 

I agree, bfgs will probably be the lightest. But they also run small and have weak sidewalls. Which is why they are light in the first place.

Remember a 37 inch tire being "light" is deceiving. A 37 inch tire that weighs 68 pounds is not the same as a 32 inch tire that weighs 68 pounds. The 37 puts much more wear and tear/stress on parts.

Think of it this way: put a 10 pound weight in your hand and make a circular motion, not a big deal/easy. Now put a 10 pound weight in a two foot long tube sock and spin it around. Much different!

Good analogy, weight isn't what gets you, it's leverage. Weight will have an impact on your housing, unit bearings, flanges, ball joints, and Cs, but diameter is what will break your shafts and ring&pinion.

 

Duratracs do not come in a 37.

The orginal BFG KO came in under 70 pounds the KO2 is 73 I believe.

The lightest I know of are the Kanati Mud Hog at 68 pounds.

Mastercraft MXT is 72.

 

Remember a 37 inch tire being "light" is deceiving. A 37 inch tire that weighs 68 pounds is not the same as a 32 inch tire that weighs 68 pounds. The 37 puts much more wear and tear/stress on parts.

Think of it this way: put a 10 pound weight in your hand and make a circular motion, not a big deal/easy. Now put a 10 pound weight in a two foot long tube sock and spin it around. Much different!

 

Remember a 37 inch tire being "light" is deceiving. A 37 inch tire that weighs 68 pounds is not the same as a 32 inch tire that weighs 68 pounds. The 37 puts much more wear and tear/stress on parts. Think of it this way: put a 10 pound weight in your hand and make a circular motion, not a big deal/easy. Now put a 10 pound weight in a two foot long tube sock and spin it around. Much different!

That analogy is only partially true. Swinging the sock at a greater distance becomes more difficult because it creates an out of balance condition. As with a round tire if you distributed the 10 lb weight evenly around the circumference then it would be a spinning disk that weighs 10 lbs, not that difficult. The problem IMHO, is the gyroscopic forces that are generated. Bigger wider heavier taller becomes a bigger and heavier gyroscope. The thing about gyroscopes are that they resist change of direction. Kind of the same principle with a flywheel. That's why all the steering components and bearings bushings etc. take such a beating. In the motorcycle world it is called unsprung weight. Unspung weight is the enemy of a good handling bike.