Originally Posted by jmar896
. . . Those are automatic tire chains by onspot. There nice, but expensive. I'd get manual ones if I use chains.
We had them put on a big mobile office my former employer built years ago. The boss (a former fire chief who was familiar with them) called us all into his office, made each one of us look him in the eyes, and repeat "Maximum speed 20 MPH" (or was it 25?). Either way, the speed limit was posted on the dash next to the switch. I never had occasion to try them.
The insta-chains are for getting you moving when you are just spinning your wheels. They won't help keep you from rear-ending a 4 wheeler because you are coming down an ice-covered hill too fast.
The alternate option is automatic sanders. These look like dual exhausts hanging part-way down in front of the drive tires, ready to spit sand or salt onto the snow or ice. I've seen the sander pipes installed on a handful of Skoolies and fire trucks around here instead of insta-chains, but I have never seen a driver using them.