Video of installation of Tire Chains on a small garden tractor. and snow blower.

http://www.tirechain.com/Tire-Chains-Lawn-Tractor-Installation-Menu.htm

Tire chains are designed to fit a range of tire sizes and tread designs. The overall length of the chains may be longer than necessary. As long as the cross chain width is correct, the overall length can be shortened by using repair links to eliminate slack or by removing 1 (or more) cross chains.

For repair couplers technique using forged pins or quick links, please see:
http://www.tirechain.com/Tire-Chains-Length-Adjustment-w-Repair-Links.htm

Or shorten the chain by prying the cross chain hook open and removing the entire cross chain. The hooks holding the cross chain to the side chain are not hardened and can be opened with a chisel or vise. See http://www.tirechain.com/tire_chainmounting_instructions.htm .