Automatic, drop-down tire chains...anybody using them ?

This is ancient history, but I drove school buses in Estes Park back in the early mid 80s equipped with drop down chains. Probably logged several thousand miles on them.

They worked well if you followed a few rules. They did have a speed restriction. Can't remember what it was, but if you drove too fast with them engaged they would break the chains off. When coming to a stop I would activate them at about 10-15 mph so that when I came to a stop they would be under the tires. Same thing when starting. I would turn them off after speed reached 10-15 mph. If the ice/snow was patchy with dry pavement showing it is problematic. They drop down chains to require maintenance as the chains would sometimes break off.

I use them every winter - we have On-Spot chains on all our fire apparatus. As mentioned before, they operate from an air system that pushes a drive wheel down against the inside of a rear tire. Great on icy roads - NOT good in really deep snow, mud, or especially rutted roads... The drive mechanism "can" unit is fairly bulky, so when activated it hangs down pretty close to the road surface to let the drive/friction wheel contact the inside of the tire. This means you are dragging this bulky item thru deep snow. In mud and when we deal with frozen ruts, if the tire drops in to a rut that is more than 3 or 4 inches deep, you risk catching and damaging the drive wheel/mechanism for the automatic tire chains. They are ideal for surfaces that quickly/suddenly become slippery like in an ice storm or on packed snow on a roadway, since we might need to deploy them, and then de-activate them multiple times on a single response. But for deep snow/mud they can actually be a hinderence. The owner of the company installed a set on his Jeep Cherokee for demonstration purposes, but that is the only time I have seen them on anything other than large chassis. ST

I used to drive a school bus south of Bend Oregon equipped with drop down chains. Went over Lava Butte summit 4 times a day, twice in the early morning and also drove through Sunriver and Spring River regularly before the snow plows got there. On the large diesel pusher bus I drove the chains did very little and I rarely used them. Performance is not even close to real tire chains but they did fit the legal requirement for "tire chains". On a school bus the driver can't get out and put on real chains when the bus is full of kids.

They need an air compressor or air system so the chains can extend outward. For a larger vehicle, no big deal.

Were I living up north, I'd consider getting them. Heck of a lot easier to flip a switch than to attach chains.

they seem to work great around here on school buses when we have snow or ice storms.

Not sure how well they would work in deep loose mud, might just sink in.

the school bus ones around here have a rubber tire that is rotated by the drive wheel to spin the chains around once they drop down. kinda like the old rubber tire drive for a bicycle light generator.

We went to Alaska for the Iditerod in 2011 and saw them all over, especially in Fairbanks and the snowier interior. Looked like they worked fine to me. I never saw anyone with only one, or one working and one working, or pieces along the roads.

A set came on an ex-ambulance chassis I bought-took them off-most school buses here have them as standard equipment-I've heard that when it's cold they freeze and are non-functional. I don't know if they'd accomplish much in deep mud?