I bought these last year and finally got a chance to use them. I had dug myself in at the rear tires. I used the boards to dig out to the bottom of the tire and put it under it. I tried to take it easy but the tires spun on the board and all of the knobs came off instantly. I wasn't able to get out and was pulled out by someone going by. He did recommend not throwing the board away but putting short bolts in it and it will make it more reliable. I will take his advise. When I use them again with bolts I will update my review.