How to Patch a Bike Tube
At some point you will find yourself stranded on the side of the road with a flat tire How, exactly, do you patch a bicycle tire, and fix a bike tube?
Once you have mastered replacing a bicycle tube, it’s time to learn how to patch a punctured tube. This is an easy and handy skill, and it provides you with a roadside solution in case of a flat tire. The skill can even be used to turn that old punctured tube into a spare!
A small patch kit can be purchased at your local bike shop. This kit contains all the essentials for changing a tire This can come in handy in the event of a flat or if you choose to patch the punctured tube later at home.
First, remove the punctured tube. (Need a refresher? Check out this article: How to Change a Bike Tube.)
Once the tube has been removed, locate the puncture by inflating the tube and listening for the hissing of air seeping from the tube.
Backroads Pro TipIf you’re having difficulty locating the hole, try wetting the tube with a water bottle or wet rag or submerging the tube in water. Then you just need to watch for bubbles!
Locating the puncture allows you to determine the cause of the flat. If only one hole appears on the outside of the tube, then road debris was likely the cause of the flat. Inspect your tire—inside and out—and remove any debris that might still be embedded in the tire. Otherwise, this remaining debris might cause another puncture in your new tube.
If one hole appears on the inside of the tube, it is possible the rim tape shifted and exposed the sharp edges of the spoke below. Check the position of the rim tape, and adjust it, if necessary.
If two holes appear side by side, this is called a “pinch flat.” This occurs when an underinflated tire comes in contact with a hard surface that pinches the tube between the rim and the object. This causes two holes in the same location but on opposite sides of the tube. This is also commonly referred to as a “snake bite.” This tube should not be repaired or patched
Backroads Pro TipA pinch flat can easily be avoided by maintaining adequate air pressure in your tires.
Note, a hole at the base of the valve stem is difficult—if not impossible—to patch, and in this case, the tube needs to be replaced with a new one.
After locating the puncture site, you can now patch the tire.
Clean and dry the area well, remembering to always follow the directions on the patch kit. Use a small piece of sandpaper to roughen the area around the puncture. This will aid in the bonding of the patch to the tire. Create a rough area slightly larger than the patch you will be using.
Next, apply a small amount of vulcanizing fluid or glue from the kit. Cover an area slightly larger than the size of the patch.
Backroads Pro TipDo not apply the patch immediately after adding vulcanizing fluid or glue. Allow the liquid to sit for several minutes and become tacky before applying the patch. You can tell the glue is ready when it has lost its shine and taken on a dull sheen.
Apply the patch by peeling off the foil backing and exposing the smooth surface. This will make contact with the tire and glue. Position the patch directly over the puncture, and use your thumbnail to apply pressure. Flatten the patch from the center out to the sides, working all the way around the patch.
Allow the patch to sit for several minutes as it bonds to the tire. Slowly and gently peel the clear plastic from the patch. If the edges of the patch begin to pull away from the tire, again use your fingernail to apply pressure to the edges of the patch, and allow it to sit for a couple more minutes.
Once the clear plastic has been removed, check the success of your patch job by inflating the tube and allowing it to sit for several hours (or even overnight). Or, again submerge the tire in water and check for bubbles. No leakage? Job well done! Notice a stream of tiny bubbles? Bummer. Your patch job did not create an airtight seal, and the tube should be discarded.
Continue practicing this skill on old tubes until you become successful in creating an airtight patch. Soon enough you’ll be a champion of knowing how to patch a bicycle tube!