Bicycle tire levers are small plastic tools which are used to pry a bicycle tire off of the rim. You could also use a screwdriver or the handle of a spoon to accomplish the same goal, but you would be running the risk of damaging your tire with the metal tool. Bicycle tire levers can be purchased most places bikes are sold.
Pry the flat side of the first bicycle tire lever under the tire along the rim. Make sure you get the lever under the inside edge of the tire.
Bend the tire lever back towards the spokes on the bicycles. Tuck the lever under one of the spokes to hold it in place. Doing this will cause the tire to pull away from the rim in the spot where you placed the first lever.
Take a second bicycle tire lever and insert it under the time of the bicycle approximately 4 to 6 inches away from the first one. Bend it back towards the spokes and use it as leverage to work more of the tire off of the rim.
Remove the second lever, move it another 4 to 6 inches away and insert it back between the tire and the rim. Repeat the process of bending the lever back and prying the tire off the rim.
Continue working the lever around the tire until you have enough of the tire off of the rim to finish removing it by hand.