I made no change to my statement(s). WE are talking about traction in the winter are we not? R-1's are just about helpless in icy or previous plowed/hard run in roads. You can't force a tire to get traction if it can't grip the surface or penetrate the surface. The R-1's have no sipes and can't penetrate so they don't get good traction on a hard surface. If you are talking deep snow, then yes, r-1's are in their element because the lugs have something to get a hold of. `If you are staying within the limits of the load ratings of the machine, an extra thousand lbs of weight isn't going to make a noticeable difference in the traction. You have made no appreciable change to the coefficient of friction between the tires and the ice/road. I don't drive in deep snow when I'm plowing, I drive in the cleared portion of the road right behind the plow I'm pushing.
I think I have a much heavier tractor than you and 4wd so I can absolutely speak to the lack of effect that weight has on such a machine. (I also have a smaller machine with r-4's that is equally helpless on ice or hardpack) That is precisely why I have added front and rear chains, wheel weights, loaded tires, and a 1700lb counter weight. (11Klbs+ total) Now, I see your eyes lighting up reading this so I will explain. The counter-weight is for the loader. I can easily lift the rear end off the ground with the loaded tires and wheel weights. That's why I made it. The wheel weights and loaded tires are for farm work in the summer time. These JD utilities are far to light from the factory to keep heavy implements from pushing them around. I can guarantee that if I took my chains off, I would not be able to push my snowplow up the hill out of my driveway, regardless of the 3klbs that I have added to the machine. I will agree that the weight improves the traction of the CHAINS a lot. It really forces them into the ice and I have no problems navigating my hillsides anymore.
I agree that my replies to your comments were not in regards to the op's comments/question. I have directed my comments at him and you respectively.