They do work but one caution would be to think about the weight you put on that single tire. The reason I say this is because last year I had the tread come off one of my 4 boat trailer tires. Used a couple of blocks on the good tire to lift that one off the ground. Changed it and went on but 1 mile down the road I see the tire I lifted with part of the tread wobbling back and forth. I had broken some belts picking it up I guess. Maybe it was about to go like the other one did. Who knows, but on a large 5th wheel you could easy put 7,000 lbs on one tire picking it up that way. Many will say it works fine but for me it did not. Just something to think about.