Before you ride.
Begin by ensuring you carry all that you need to change you flat.
• Spare tubes (make sure they match your current tire size; example: 650 or 700)
• Tire levers and / or Speed Lever
• A bike pump or CO2 Cartridge (and inflater)
• A patch kit (in case you run out of tubes)
• Boot (cut from an old tire) to place inside a sliced tire

Step 1
The first thing to do when you flat is to get off the road as best as possible to a safe area where you can change the tube. Since the rear wheel is more difficult to change (because of wheel removal and replacement), we will change the rear. The next thing is to place the chain in a position that makes it easy to remove the rear wheel. Change the rear gearing so the chain shifts to the smallest rear cog and spin the cranks. Change the front gearing so the chain shifts the small gear in the front.

Step 2
Open the rear brake lever. You will notice the brake calipers separate allowing room for the rim to pass through during wheel removal.

Step 3
Open the rear quick release and unscrew the release a few revolutions to allow removal of the real wheel. .

Step 4
Take note of how the chain wraps around the rear cog set. This is the position we want to return the wheel to when we are done. Lift the bike off the ground and remove the rear wheel by pushing towards the ground (or rear if your drop outs face backwards) through the opening in the drop-outs. .

Step 5
Before extracting the tube, check the outside of the tire for the cause of the flat; wooded splinter, metal sliver, glass, nail, etc… If found, carefully remove the item and take note of the area so that you can check the inside of the tire after removal. If not, don’t panic. Select the section of the tire opposite the valve stem. Insert two tire levers into the tire, about 3 inches apart, hooking the tire’s lip with the tire levers. .

Step 6
Flip both levers down simultaneously brining a 3 inch section of the tire up and over the side of the rim.

Step 7
Select one of the levers and slide it around the rim until the remainder of the tire lip comes to the outside of the rim. A speed level will also work. The flat tube can now be removed. Do not remove the tire. Before inserting the new tube, check the inside of the tube for damage. Pull your glove over the your finger tips and slide your fingers around the inside if the tire slowly looking for the cause. Carefully remove the cause.

Step 8
Prepare the new tube by opening the valve and inserting just enough air to un-flatten the tub. Do not close the valve. It’s OK if air escapes as you replace the tube. Insert the valve part of the tub into the wheel first from the same side you removed the previous tube. Working your way around the wheel, place the tube on inside the tire rim. If there is a chance the tube will protrude through the tire where it is damaged, insert the boot between the tube and the inside of the tire. This will keep the tube inside the tire.

Step 9
Now its time to replace the lip of the tire back inside the lip of the rim with the new tube inside the tire. This time start on one side of the valve stem. Slip the tire over one tube and inside rim. Continue this towards and beyond the valve stem working your way around the rim. As you work you way around, ensure the tube is inside the tire and not pinched between the tire and the rim. This may be a little tough at first, but it gets easier with practice. Just slip the tire on a few inches at a time and you'll eventually get it. The last portion of the tire may be difficult. The newer or narrower the tire, the less it will give (stretch). You may choose to use your tire levers to push the tube into the rim.

Step 10
Once the tube is in and the tire fully replaced, squeeze the tire and look see if the tube is pinched between the rim and the tire. Work your way around the tire. If it is, you may need re-do the area of the tire freeing up the pinched tube. Inflate the tube.