BICYCLE
REPAIR
Fixing A
Bicycle Flat Tire
by
Jim Langley |
|
This is
the second flat-tire-repair article on my site. I offer two because
some people prefer the photo-and-caption-style instructions and others
prefer more explanation, which I provide in my other fix-a-flat
story.
If you
really want to be an expert, read them both! You might also want to
learn to remove and install bike tires
by hand only. That way youll be the fastest flat fixer when
riding with friends and amaze them with your pro skills. |
What
You Need: As
shown in the photo on the right, you dont need many tools to repair
a flat tire. From left to right: get a pump,
a spare tube and tire
levers.
Id also recommend carrying a patch
kit, which comes in handy if you get back-to-back flats. And,
get the full-on kit, rather than the so-called glueless kit
because the regular patch kits fix the tube as good as new, while the
other type is a temporary fix.
Also, the longer the pump is, the easier it will be to inflate the tire.
If you must get a mini because thats all you can carry or mount
on your particular frame, be sure to test it before buying to ensure that
it does the job (some minis require way too much pumping).
Read more about what
to put in your take-along bicycle repair kit. |
|
Open
the brake:
As soon as you get that sinking
feeling or hear the hiss of escaping air, let your ride partners know
you have a flat (so they wont disappear over the horizon) and stop.
If its a rear flat (it usually is), shift onto the smallest rear
cog. The first step in wheel removal is opening the brake (photos),
which makes it easier to get the wheel out.
Open sidepull brakes by fully rotating the little
lever on the brake upwards (a).
Open linear-pulls (also called V-brakes) by lifting the end of
the noodle out of its holder (b).
Some sidepulls are opened by pressing a button on the lever. Look for
this if theres no lever on the brake. Open cantilever brakes
(these feature a cable that runs over the top of the tire) by lifting
the cable end on one side out of its holder.
|
Tips
Be safe! Work off the road/trail so a semi doesnt flatten you!
While its possible to get the flat tire through the brake without
opening it, it wont be so easy reinstalling the wheel when its
fully inflated. Thats why we recommend opening the brake first.
If you have disc brakes, theres nothing to open. The wheel
will come right out of the brake with no muss, no fuss.
![](wrench_images/flattireopenbrake.jpg) |
![](wrench_images/flattire2removewheel.jpg) |
Remove
the wheel:
Open the quick release
(or loosen the axle nuts) on the wheel with the flat and lift the bike
to remove the wheel. To extract rear wheels, it helps to pull the
derailleur back slightly to clear the axle parts as the wheel passes through
(main photo).
For fronts, youll probably need to hold one side of the quick
release and turn the other counterclockwise to create clearance to get
past the wheel-retention tabs on the fork (inset photo).
Tips
Never force the wheel out! If its stuck, determine whats
holding it in place and free it.
When the wheel is removed, lay the bike on its left side so you dont
damage the derailleur or get dirt in the drivetrain.
|
Remove
the tire and tube:
Remove the valve cap (not shown) and nut (sometimes found on Presta valves:
inset photo). For Presta valves, unscrew the tip (inset
photo) and press down to let all the air out. For Schraders, poke
the end of your tire lever into the valve to release all the air. Starting
directly opposite the valve, wiggle a tire lever beneath the tire edge
(called the bead) and pry down to lift. If possible, hook
the lever on a spoke (many levers are made to do this), or hold it in
place. Place another lever about 6 inches away from the first and pry
here (main photo). Continue with your third lever until you can
get one side of the tire off. Then reach inside and extract the tube.
Pull the other side of the tire off the rim or pry it off with your levers.
Tips
If you have trouble getting the tire off, make sure all the air
is out of it. Even a little air can make the tire a lot tighter.
The Cobra
Tire Tool is a nifty lever that uses your bicycle to pry one side
of the tire off the rim.
Some cyclists prefer to remove only one side of the tire to ease reinstallation.
The disadvantage is that its harder to check inside the tire to
find whatever popped the tube.
|
![](wrench_images/flattire3removetire.jpg) |
![](wrench_images/flattire4findglass.jpg) |
Inspect
the tire:
Its important to find whatever caused the flat and remove it.
If you dont, the sharp item might still be in the tire where itll
just pop your new tube. To find it, remove your glove (or use a rag),
and run it around inside the tire in both directions (photo).
If something sharp is still stuck in your tire, itll snag the
glove. Remove it. If you cant find anything, it probably got knocked
out during the disassembly procedure.
Tips
Check inside the rim, too, to ensure the rim strip covers the nipples
and anything else sharp.
As long as the hole in the tire is about 1/4-inch long or less, its
okay to reuse it.
If the tire has a large gash in it, simply place a dollar over it
as you reinstall the tube. Itll reinforce the tire at the hole
and get you home. Replace the tire ASAP (dont forget to save
the dollar!).
|
Install
the tube & tire: 4 Easy Steps
1. Inflate the new tube just enough to round it out and remove
any wrinkles, and place it inside the tire. Stand the wheel up (rest
it against your shins) with the valve hole on top and hold the tire/tube
over the wheel so that the valve is on top (inset photo).
2. Place the valve partway into the hole and
simultaneously push the part of the tire bead thats at the valve
and closest to your legs onto the rim. With both hands moving downward
away from the valve, finish working the bottom tire bead (the one
closest to your legs) onto the wheel all the way around. If it wont
fit onto the rim, check that the valve is inside the tire, not trapped
beneath the bead.
Youll find step 3 under the photo to the right.
Tips
Tubes that are slightly narrower than the tire fit fine and are
easiest to install (for example: use a 700 x 20c tube in a 25c tire
and a 1.5-inch tube in a 1.9-inch tire).
A trick to create slack and ease tire installation is to go around
the rim squeezing the tire beads into the rims center (the deepest
portion).
If you locate the tire label at the valve, youll have a reference
point when searching the tire for what popped the tube.
|
![](wrench_images/flattire5installtire.jpg)
3.
With one bead in place, tuck the tube fully inside the tire and on top
of the rim, which will cause the other bead to rest flush against the
rim. Work this bead on, starting at the valve as you did with the first.
You may have to push the valve into the tire to provide clearance for
the bead. Once youve got it started, work your hands away from the
valve pressing the bead onto the rim around the wheel. 4.
With a few inches of bead left to pop onto the rim, the tire will resist.
Let all the air out. Crouch and rest the wheel on your knee to have
something to push against. Now, hold the bead in place with one hand
and with your stronger hand, push down to roll the stubborn section
onto the rim with the heel of your hand (main photo). But dont
try to pop it on all at once. Install an inch at a time, moving your
hand along until youve fully installed the tire. Got it? Way
to go!!
|
Tips
Not
all portable pumps have the power to fully inflate all tires. But thats
okay. You only need enough air to make the tire firm enough to ride
on.
The first time you fix a flat it may take 30 minutes to an hour. But,
with practice, youll get much faster. Experienced cyclists can
easily repair one in 10 minutes.
If you ride regularly and havent fixed a flat yet, practice at
home to build your confidence. |
Inflate
and seat the tire:
Place your pump on the valve and inflate the tire. To prevent valve damage,
brace it by wrapping a finger behind a spoke (photo left) so youre
pushing against your hand, not the valve. Inflate the tire until its
just firm (not fully inflated). At this point, inspect the tire to make
sure its seated, which means that its sitting
correctly on the rim.
If the tube gets trapped beneath a bead (photo top),
inflating further may blow the tire and tube off the rim!
Theres a bead line on the side of the tire (photo bottom)
that should be equidistant from the rim all the way around on both sides
of the tire. If its not, or if you see a section of tube peeking
out from under the rim, let the air out, work the tube back into place,
reinflate partway and check the tire again.
When its seated correctly, inflate it fully. Install the valve
nut (if your tube uses one) and cap finger tight (overtightening the
valve nut can damage the tube and make it difficult to loosen it when
you need to fix a flat).
Reinstall the wheel in the frame, close the brake quick release or reattach
the noodle or cable and youre ready to ride!
|
![Back](../buttons/back.gif)
to the WRENCH page
|