JHAP:
When you get the chains, I think they also make tensioners to help keep them tight on the wheel.
Drag marks, huh? Interesting. I'm betting on a cat. If the prints were 2" or so in diameter of the chaser, then I think Bobcat. 3" or larger I'd guess Mt. Lion. How far apart were the tracks when the chaser/chasee were running?
Coyotes usually eat on the spot, and you're right, the bears should be hibernating, or close to it by now. If it was a bear, I think the prints would be pretty big in that snow.
If you're prepared, winter is a fun place to visit, but I prefer summer. That's why I like So. Cal.!
I looked at Off Road Warehouse for the chains and tow strap, but couldn't find any on-line. I think Pep-Boys carries chains, or you probably could do a one-stop shop on the internet. With as popular as it is to go out and play in the desert, I'd think that one of the off-road shops in the area would be able to set you right up.
