Living in NH, I have tire chains not because of any law, but because I NEED them to get home!!! As compared to the "ladder"-style chains, I have switched over to Diamond-pattern. Much easier to put on, no need to lift tire or drive onto chains. Also much smoother running. Tirechain.com is one source - there are several others. Also meet reduced-clearance "class s" applications. The "not recommended for diesel" refers to the extra torque from diesels in large trucks - I haven't found that an issue myself. Here's a link showing installation/pattern of a diamond chain. Maybe someone can make a "clicky"-thing... http://www.tirechain.com/outdoorexplorer.htm