No. When I tested it the tire was full of air. The jack will lift a maximum of 12 3/8". The reason I carry some pieces of 2x6" lumber is to allow me to raise it higher if necessary due to the flat tire or the terrain. When I tested it last spring I honestly can't remember if I need to use a piece of 2x6 or not. I do not believe I did as I do remember the jack fit under the jack point and lifted the trailer just fine. Once our long 7 month winter ends I'll test it again with a full tire and a deflated one. I also plan of dropping the spare to check its condition and top it off with air.dsfdogs said:@bergger have you tested this jack if the tire is flat? Thank you for the product suggestion.