Navigation bar


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 you’ll 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 don’t need many tools to repair a flat tire. From left to right: get a pump, a spare tube and tire levers.

I’d 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 that’s 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 won’t disappear over the horizon) and stop. If it’s 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 there’s 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 doesn’t flatten you!

While it’s possible to get the flat tire through the brake without opening it, it won’t be so easy reinstalling the wheel when it’s fully inflated. That’s why we recommend opening the brake first.

If you have disk brakes, there’s nothing to open. The wheel will come right out of the brake with no muss, no fuss.


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, you’ll 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 it’s stuck, determine what’s holding it in place and free it.

When the wheel is removed, lay the bike on its left side so you don’t 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 it’s harder to check inside the tire to find whatever popped the tube.

Inspect the tire: It’s important to find whatever caused the flat and remove it. If you don’t, the sharp item might still be in the tire where it’ll 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, it’ll snag the glove. Remove it. If you can’t 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, it’s okay to reuse it.

If the tire has a large gash in it, simply place a dollar over it as you reinstall the tube. It’ll reinforce the tire at the hole and get you home. Replace the tire ASAP (don’t 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 that’s 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 won’t fit onto the rim, check that the valve is inside the tire, not trapped beneath the bead.

You’ll 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 rim’s center (the deepest portion).

If you locate the tire label at the valve, you’ll have a reference point when searching the tire for what popped the tube.



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 you’ve 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 don’t try to pop it on all at once. Install an inch at a time, moving your hand along until you’ve fully installed the tire. Got it? Way to go!!

Tips
Not all portable pumps have the power to fully inflate all tires. But that’s 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, you’ll get much faster. Experienced cyclists can easily repair one in 10 minutes.

If you ride regularly and haven’t 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 you’re pushing against your hand, not the valve. Inflate the tire until it’s just firm (not fully inflated). At this point, inspect the tire to make sure it’s “seated,” which means that it’s 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!

There’s 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 it’s 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 it’s 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 you’re ready to ride!



Back

to the WRENCH page