First-you must remove the wheels. Then let the air out of the tires. I use my bench vise to squeeze the tires in, and a large screw-driver, or flat sharpened bar, to break the tire bead loose. Also, a liberal application of light oil does wonders with the job. I bought a 3 ft. length of threaded steel rod, a bunch of large flat washers to fit the rod, And eight nuts to fit the rod. Two nuts go on so you can squeeze the rod in the vise, and another nut above the vise, then a flat washer ,then the wheel, then several more washers and two nuts. Tighten all together, and using a large screw-driver, get the bead loose from the rim, and using the large screw driver, pry the tire off the rim, then the other side of the tire. By this time, you will wish you had never started the job. Best to ask at the tractor seller's place if they know somebody who can do the job! Ain't fun--nawsuhh!

My Bad -- I just need to remove them from the mower and was told it was difficult. The front wheels were attached with an 'e' clip and that was all, and they were pretty easy to remove -- but they said that the back ones are much more difficult to take off of the mower. I will then take them to Tractor Supply and have them to replace them --- sorry about not being any clearer!!! Thanks bunches and bunches :)