How To: Fix a Flat Bike Tire

How To: Fix a Flat Bike Tire


Take 73! On unavoidable downside to cycling… No stop, take 74! Never trust the video team! How To: Fix a Flat One unavoidable downside to cycling is the dreaded flat tire. Fortunately, a few quick steps will have you up and on your way in no time. To fix a flat, you’ll need a spare tube, tire levers, either a floor pump or a CO2 inflator, and a seat bag to store your tools. You can find all the tools you need at your local Trek retailer or on trekbikes.com. We’re going to fix a flat rear tire, but the process is basically the same for both the front and rear tires. Start by removing the wheel. First, shift the chain the hardest gear, which is the smallest cog. Then, release the brakes. How you release the brakes depends on what type of brakes you have. Most road bikes have a brake release lever that will release brake tension. For disc brakes, there’s nothing extra you need to do. Disc pads are fixed and the disc will move in and out between the pads. Next, open the quick release. Gently pull the rear derailleur towards you to slide the wheel out of the dropouts. If your bike has thru axles, you will need to unthread the axle until you can easily pull the entire axle out of the frame. Then the wheel can be easily removed. Set the bike down on the non-drive side. Once the wheel is off the bike, start near a spoke. Use the scooped end of your tire lever to grab the edge of the tire and work it over the edge of the rim. Attach the hooked end of the tire lever to the nearest spoke. Use the scooped side of your second tire lever to work more of the tire over the edge of the rim. Once you have a few inches over the rim, work your way around the rest of the wheel. Completely remove one side of the tire from the rim. Remove the valve nut. Push the tire near the valve stem away from the rim, and pull the valve stem out of the wheel. Then remove the rest of the tube. There’s no sense in adding a new tube if the cause of the flat is still in your tire. So first check to make sure the tire is clear of debris. Visually inspect the outside of the tire. Carefully run your fingers through the inside of the tire, feeling for anything sharp. Remove anything that could cause another flat. Sometimes glass or other small, sharp objects can cause a flat. So, please be careful when inspecting the inside of the tire. If you don’t find anything, you may have a pinch flat. Pinch flats happen when an underinflated tire hits a square-edged bump. The tire can become pinched between the rim and the bump, causing a flat. Now that we’ve checked our tire and removed any flat-causing culprits, we can replace the tube. When you remove the tube from your seat pack, it will be flat. It can be hard to place a flat tube in a wheel, so inflate it with just enough air to give it some shape. Start back at the valve stem hole, and insert the valve stem. Work your way around the tire, tucking the tube under tire all the way around. Now that the tube is in place, let’s get the tire seated back in the rim. The tightest part of the tire is next to the valve stem. Starting there, use both thumbs to push the edge of the tire back onto the rim. Continue using your thumbs to tuck the tire back on to the rim, working your way around the wheel. The tire will get tighter as you work your way around. Your thumbs are the best tool for this job. But, if they’re just not cutting it, carefully use the scooped end of the tire lever to press the rest of the tire back inside the rim. Be careful not to damage the tube with the lever. We’ll want to give one last check to make sure that the tube isn’t pinched between the tire and the rim. Do this by gently pushing the tire to the side as you work your way around the rim and look for any obvious pinches. Reinstall the valve stem nut. Using your pump, re-inflate the tire. The flat is now fixed, and it’s time to get the wheel back onto the bike. Put the rear wheel back in the frame and set the chain on the smallest cog. Pull the rear derailleur back out of the way and let the wheel slip into the dropouts. If you have disc brakes, make sure the disc is inserted between the fixed pads. Insert the axle through the frame and hub. Then, thread it in and close the lever. If you have a quick release, close the lever, making sure you have proper tension. If you’re using a type of brake other than disc, be sure to close your brakes too. Lift the rear wheel and give the bike a quick pedal to ensure everything is running smoothly. Congratulations, you are now flat-free! Enjoy the rest of your ride.

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  1. I always use a cloth to check inside tire for objects imbibed in the tire. The cloth will catch what ever it is that caused the flat without cutting your hand.

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