In this, the first installment, of Technical Tuesdays, we'll cover one of the most common mechanicals: the dreaded flat tire! Inside you'll find step by step instructions and a How-To video to guide you through this 'must know' fix!
Read On...
Being able to fix a flat tire, whether it's while you're out on the trail or back at home, is a mandatory piece of bike knowledge. While a lot of readers out there no doubt already know how to go about replacing their tube, those who are new to the sport or have not yet been forced to learn how may not be so adept at it. We're going to keep it simple for this first installment of Technical Tuesdays and show you how to repair your flat. If you haven't had a flat yet and don't think you need to know how, your time is coming!
Watch the video to learn how to easily change a flat tire
Step By Step Flat Tire Instructions Tools needed: Tire levers (
do not use screwdrivers please) and a
pump  |
| Tire levers, pump, and a new tube ready for action |
Flat tires have to be one of the most common mechanical problems faced by mountain bikers. Nothing kills the day's flow more than popping a tube halfway through a ride, it's just a bummer all around. While fixing a flat is a pretty simple job that should only take a few minutes with practice, it's something that a surprising number of riders struggle with. Even if you already know what to do (
besides call your mom to come get you), there are a few tricks that can make the job quicker and easier. These instructions assume that you've already removed the offending wheel from the bike, and while we're using a standard tire and tube setup, many of these steps still apply if you manage to flat your tubeless setup and simply want to put a tube in to get you out of the bush.
There can be a number of reasons why you no longer have any air in your tube. One of the most common is surely the dreaded pinch flat. A pinch flat is as it sounds, the tube was pinched between the rim sidewalls and the tire hard enough to cut it. The more air pressure you run, the less chance you have of pinch flatting, but you will have less traction at higher pressures. The other common flat tire culprit would be some sort of foreign object. Picture thorns, glass, sharp rocks and you'll get the idea. It is important to figure out why you flatted so that it doesn't happen again due to the same cause.
1. Start by removing the wheel from the bike and letting out any remaining air. This will make unseating the tire bead much easier.
2. When fixing a flat, unless the tire is damaged there is no reason to completely remove it from the wheel. You only need to remove one side of the tire in order to replace the tube. Some tire and rim combos have quite a tight fit which can make starting with a tire lever difficult. To make it easier, start by squeezing the tire bead into the center of the rim all the way around the wheel. This will make getting the tire lever under the bead much simpler.
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| First lever installed and hooked onto a spoke, freeing up both hands |
Line up the tire lever with a spoke that comes from the same side of the wheel that you are working on. Hook the spoon end of the lever under the bead and pry it up and over the rim wall, hooking the opposite end of the lever to the closest spoke. You should now be able to let go of the lever and have it be held in place by the spoke and tire bead, giving you two free hands to repeat the process a few inches to the left or right. The key here is not to get greedy and try to pry too much of the tire bead off at one go. Some tires will only require one lever to remove, but some may need two or even three. When putting in multiple levers, start within an inch or two of the lever that is already in place, otherwise it will be very difficult to get the new lever under the bead.
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| Start the second lever close to the first. If it's too far away you'll have a hard time getting under the bead |
Once a good portion of the tire bead is up and over the rim wall you should be able to slide one lever completely around the wheel and have one entire side of the tire up and over the rim all the way around. Now you can pull out the punctured tube, but be sure to keep the tube in the same relation to the tire as you remove it. Likewise, make sure that the tire does not rotate on the rim as you're removing the tube. If you're not sure what caused the flat and are worried about a piece of glass or thorn that may still be stuck in the tire waiting to put a hole in the new tube, lining up the hole in the tube with the tire will tell you where you should check.
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| You only need to remove one side of the tire's bead |
You should always take the time to figure out what has caused your flat tire. Some pinch flats are obvious, but others can be a bit of a mystery. Locate the hole on the tube by putting some air into it and holding it close to your face so that you can feel or hear the leak. A pinch flat will usually look like two parallel slits across from one another and running lengthwise on the tube, although sometimes there will only be a single cut. If there is a single small hole then it was most likely caused by something that was ran over on the trail like a thorn or sharp stone. If so, you'll need to make sure that is not still stuck in your tire's casing. Run your palm up and over the inside of the casing slowly, being careful not to cut yourself if you drag your hand over something sharp. Remove whatever you find.
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| Use your hand to check the inside of the tire for foreign objects - be careful! |
Once you're happy that you've found the cause, it's time to install a new tube. Before you put it in be sure to put a few pumps of air in to the new tube so that it takes shape. This will help keep it from being pinched by the rim, tire bead, or tire lever, when you finish it off. Start by putting the valve through the rim's valve hole and then screwing on the valve cap. Doing this keeps the valve from pulling back out of the rim as you work the tire on. Once the tube is all the way on it is time to reinstall the tire bead. Place the wheel upright on the floor in front of your feet with the valve stem in the highest position and the uninstalled bead facing out. Starting at the valve stem use both hands working away from the valve in opposite directions to push the bead up and over the rim. At the point opposite to where you started you may end up with a 6" section that is too tight to push over the rim's sidewall.
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| Reinstalling the tire bead |
This is the important part that will let you finish installing your tire without having to resort to using levers, which can easily puncture your new tube. While still holding the wheel on the floor, start opposite the remaining tight section and squeeze the bead together towards the center of the rim. What you are doing is forcing the bead into the rim's middle section where the total circumference is slightly smaller than out at the sidewall, therefore making the tire a looser fit on the rim. It may take a few tries, but you should be able to push the last tight bit of tire bead up and over the rim wall with a few strong pushes of your thumb. Once that is done you need to make sure that the new tube is not trapped between the tire bead and rim. If it is you'll be rewarded with a loud bang as it explodes at the trapped section once you pump it up. Before you put any air into it squeeze both sides of the tire together and visually check to be sure you can see any part of the tube that may have got caught during installation. Pay special attention to the thicker rubber near the tube's valve stem. Once you're satisfied that you've done it right pump it back up and you're all done!
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| Check to be sure that no part of the tube has been pinched between the tire and rim |
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