I have run them for 3 years and love them. put a pair on, one side??? sure they sell them that way but slide kicks put up less ice then wire so use 2. besides changing 1 hyfax and not the other more often makes no sense. I run with mine down all the time. Backing up destroys wire scratchers fast and when do you back up??? gas islands, parking lots? etc. also the same places you would want your scratchers down. Amazing what slidekicks have to endure and they hold up faily well. The companie stands behind them very well and replaced a set of mine for free when one came apart from the crimping.