I live in Vermont and have an open station 3520 JD with the smaller R4 tires. I use a set of hardened steel spike chains for my rear wheels (from Norway as I recall). I've used them for 4 winters and have no regrets and very little wear on them. The tractor literally "walks" over ice I can't stand on. I also have the rear tires loaded and have three wheel weights on each rear wheel. I have pretty steep grades on my 0.6 mile gravel/dirt driveway. In the swamp and fields, it may be a different situation for you. This series of tractors doesn't have much ground clearance. You may need to plow a path first! Also, if you have the large R4 tires, your choices in chains may be limited due to the tighter clearances between the wheels and fenders. I got my chains through the local JD dealer. They were pretty pricey but worth every penny.