Front wheel
Open the brake's quick release by pushing brakes together and pulling cable out of hole
Release the quick-release lever and pull the wheel from forks.
If your bike has axle nuts instead of quick release make sure you take the right size spanner with you on any rides
If not quick release brake you can let the air out or undo brake cable
If the front fork has ridges or some other component to stop the wheel unscrew the thumbnut on the side opposite the lever until the hub can pass over them.
Shift gear into the smallest cog on front and back derailleur (you will have to turn the pedals).
Open the brake's quick release by pushing brakes together and pulling cable out of hole as pic.
If not quick release brake you can let the air out or undo brake cable
Release the quick-release lever and pull the wheel out (the chain should stay on the bike)
If your bike has axle nuts instead of quick release make sure you take the right size spanner with you on any rides
If the drop out has ridges or some other component to stop the wheel unscrew the thumbnut on the side opposite the lever until the hub can pass over them.
Take of dust cap and let out any remaining air (by pushing in the pin in the valve after unscrewing the little round nut but not removing in the case of Presta.If there is a nut on the base of the valve remove it and place it somewhere safe.
Push valve into the tire as far as possible to create more space for tire bead.
Manipulate the tire sidewall by hand working all around to push bead towards the deeper centre section of rim.
Place the end of the long part of the L-shaped tire level under the tire bead over the top of the side of the rim, with the short end of the tire level facing towards the centre of the wheel. Use it as a lever to push the bead of the tire up and over the side of the rim, hooking the notch, in the short end of the lever onto a spoke.
Do the same with second tire lever about 4-5 spokes further to one side.
If necessary do the same with the third lever (first level may fall off)
At this stage you can remove the first tire level
Remove the entire side of the tire cover off the rim by hand, working around gradually from the area where you used the tire levers
Pull most of the inner tube out from between the tire cover and rim. Push the valve through the hole and remove the entire inner tube.
Check the condition of the tire cover inside and out, and remove any sharp objects that maybe embedded using tweezers if you can't get them out by hand
Check the state of the rim tape that covers the deepest section of the rim bed to make sure it is intact and has the right width (it must cover the deepest portion of the rim but not go up the sides) and no spoke ends are poking through
Fixing puncture
If you are replacing tube go to installing tube otherwise check the entire surface of the tube, starting at any location you may have identified as the cause of the puncture. If you cannot easily find the location of the leak inflate the tube and pass it along your ear or cheek to listen or feel where air escapes. If still no luck dip the inflated tube in a basin of water and watch for air bubbles that's the location of the (or at least one ) hole. Mark the hole by drawing a circle around it bigger than the patch. if the tube is wet dry it.
Rough up the area with sand paper or anything abrasive then wipe it clean.
Apply a thin even layer of rubber solution to the area to be patched slightly bigger than the patch required and let it dry for about 1 min in hot weather 2-4 mins. in cold weather.
Pull one end of the protective layer (usually aluminium foil) from the patch without touching the adhesive side of the patch and apply the patch to the treated area of the tube (centred on the hole) while pulling off the remainder of the protective layer.
Apply firm pressure to the entire patch for about a minute squeezing by hand and rubbing it .Check to make sure the patch has adhered properly if not redo. Sprinkle some French chalk or dust over the patched area to prevent it from sticking to the inside of the tire cover.
Inflate tube and wait about a minute or two to make sure it is not leaking and if it is repeat the repair for the same or any other hole you may find.
Let the air out again and reinstall the inner tube
Install the new or repaired inner tube starting at the valve carefully making sure it is embedded properly in the deepest section of the rim under the tire.
Inflate the tube just a little so it is no longer "limp" but does not have any pressure either.
Starting at the valve pull the tire cover back over the rim working it into the deepest section of the rim as you work your way around in both directions until it is in place over its entire circumference. The final part may be tough and if you use tire levers be very careful not to nip the inner tube.
Inflate the tube slightly then "knead" the sidewalls until you are sure no part of the tube is caught in between the rim and the tire bead.
Inflate the inner tube to its final pressure making sure the tube gets seated properly. it's seated properly if the ridge on the side is the same distance from the rim all around on both sides of the wheel if not let some air out then "knead" the tire working all around until it is seated properly then re-inflate to correct pressure (Note: pressure should be marked on side of tire)
Fitting wheel to bike
Front wheel
Make sure the quick-release brake is still open and the hub quick-release is open.
If there are ridges on the fork ends unscrew the thumbnut far enough for the wheel to pass over them.
Slide the wheel over the fork ends guiding it near the rim between the brake pads until the hub is seated fully at the end of the slots in the fork ends.Center the wheel at the rim between the fork blades. (leaving the same distance on both sides) and close the quick release level (in case of ridges on fork first screw in the thumbnut until the quick release level can be closed fully with slight hand force.
Lift front of bike up and tap front wheel to make sure it does not come out
Close the quick-release brake by pressing the brake pads together and putting the cable through the hole. see pic.
PLEASE MAKE SURE THE BRAKE WORKS BEFORE RIDING THE BIKE
Make sure the quick-release brake is still open and the hub quick-release is open.
If there are ridges on the drop outs unscrew the thumbnut far enough for the wheel to pass over them.
Make sure the chain engages the smallest gear and route the chain as per pic.
Slide the wheel into the slot in the drop outs guiding it near the rim between the brake pads until the hub is seated fully at the end of the drop out .Center the wheel at the rim between the fork blades. (leaving the same distance on both sides) and close the quick release level .In case of ridges on the drop outs first screw in the thumbnut until the quick release level can be closed fully with slight hand force.
Lift back of bike up and hit back wheel down to make sure it does not fall out.
Close the quick-release brake by pressing the brake pads together and putting the cable through the hole. see pic.
PLEASE MAKE SURE THE BRAKES WORK BEFORE RIDING THE BIKE