I am about to purchase a new 729T Mower with Bar Tires. In addition I want to purchase Turf Tires, they are offering the standard Turf Tires at $385 per set vs the Turf Tires at $250 that accommodate tire chains. My assumption is the difference is that they are smaller diameter to allow chains to fit under the fenders. Are there any other difference that would account for the large difference in price.