If we use single rails on our trucks and we go in the ditch you get thrown out suspension. We carry spiders in our toolbox which are basically bungees all hooked to a center ring.
If you chain up enough over the course of the winter you'll get your chains tight enough that you won't even need those. If you only chain up maybe once or twice a season they're good to have.
How to apply snow chains to an 18 wheeler.?
Comment: TurckMaroc : You are only asking for trouble if you single rails on duels. You should be using triple rails.