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.
