Recommended Tools:

(2 or 3) Long Tire Irons, A bead breaker, Tire-mounting paste

Start by breaking the beads, both beads should be broke so that one bead can follow the other as you pry off the first. You should break the bead on the side of the long bead surface (C) first so that you don't have to flip the tire over twice. then break the second bead from the short bead surface (A).

Lubricate the bead surface while breaking the bead if needed, and absolutely before trying to pry the bead off, but only lubricate the bead from the 1130 position to about 6 o'clock so that the left side of your first bite will stick to the edge of the wheel and you won't have to leave one bar behind to hold the bead and you'll be able to alternate bites with two irons.

Once the beads are loose, you need to orient yourself so the valve stem is at your 12 o'clock and then insert the tire irons at 11:00 and 1:00 wider if possible, narrower if you have to.

Insert the irons so that the lug on the back will lock onto the edge of the wheel. Then while pulling on the irons to bring the bead up over the edge of the wheel you need to be kicking or bouncing on the bead at your 6 o'clock to get it onto the inset bead surface (B) so that the bead can fit over the edge of the wheel

Once you get the first bite pull out your left iron and inset it to the right of your right iron and pry it over, if its too hard slide the iron closer to the other one with your hammer until you can pry the bead over.

Repeat until the first bead is off.

There is no need to remove the second bead if the tire is wide enough and your just doing a repair. Just set the far edge of the wheel on a block to keep it out of your way.

To remove the second bead (it's more like removing the wheel from the tire at this point) lift the tire up so that the wheel is sort of dangling from the bead and make sure the wheels inset bead surface (B) is against the lowest part of the bead and insert a tire iron at 12 o'clock and IF the bead is lubricated enough and IF the iron is long enough and IF your tall enough you should be able to let the tire drop against the iron as you lift the iron and pop the wheel out onto the ground. At this point I should probably point out that the wheel can land on your toes causing great pain.

The risk of back injury while wrestling a couple hundred pounds of tire can not be understate. If your not on the trail it would probably be well worth the money to take your tires to a local truck tire service shop and get some 18 year old linebacker type to do it for you.

Save yourself future frustration by inspecting your wheel while you have your tires off the grommet on the valve-stem should be in good condition or replaced and any rust should be treated with an acidic-polymer rust treatment like Extend, Rust-X or Qurox.

Mounting a new or just repaired tire onto the wheel is not as difficult or strenuous as dismounting one, airing it up can be tricky but you shouldn't be sweating as hard as when dismounting one.

The first and most important thing to do is set the wheel with the short bead surface (A) up so that the bead can be "stretched" over the wheel.

Lubricate the bead of the tire with the tire paste from my tools page or something similar that will not leave liquid in your tire to promote rust.

Set the valve-stem away from you at the 12 O'clock position and the side of the tire you want on the outside facing you (remember to think about this carefully if you have directional tread, your left and right tires will be opposite) 

To get the best start on the first bead let it drop hard onto the wheel and follow it with all your weight so that the bead hits the wheel with the lowest point of the bead set into the inset bead surface (B) and as much of the bead onto the wheel as possible.

With the tire iron turned so that the lug is toward the bead and just the lip of the iron hooked on the wheel pull while bouncing or pushing down on the tire, slipping the bead over the wheel and repeat until the first bead is on.

Using the same motion with the tire iron, pry the bead onto the wheel at the valve-stem and stand or bounce on the bead forcing it down onto the inset bead surface (B) while working your way around the bead until the last edge of the bead is pried over the wheel (if the bead won't cooperate and follows you around the wheel, you can either get a helper to hold it down with an iron or use a pair of vise grips with a rag or piece of rubber to protect the wheel to hold it by clamping onto the wheel to create an anchor point)