My son asked me to help him air up his tires on his bicycle because the valve stem was crooked. His friends tried to help him and couldn’t figure it out, and it was a new one to me too. Here’s how we learned to fix a crooked valve stem on a bike.
The good news is you don’t need a new bike or even a new tire, necessarily. Crooked valve stems are caused by a deflated inner tube bunching up. Sometimes you can deflate the tire and straighten the stem, but other times you have to pull the tire and stretch out the tube.
Fix a crooked valve stem on a bike the easy way
The easy way to fix a crooked valve stem is the deflate the tire. Remove the cap from the valve and push the core down with the tip of a pencil or screwdriver while squeezing the tire. With enough luck, once you release enough air pressure, you can pull the stem back through the rim. When the stem protrudes far enough, it will stand straight on its own. Air the tire up right away and hold the stem straight if necessary.
When this works, the fix takes a couple of minutes.
Fix a crooked valve stem the hard way
When you can’t straighten the stem on its own, you’ll have to pull the tire. You don’t have to take the wheel off the bike unless you pop the tube. Carefully pry the tire off the rim with a screwdriver, working very slowly to avoid popping the inner tube. It’s easy to do that. Don’t ask me how I know. Once you have a big enough opening, slip the handle of a pair of pliers under the tire and use it to continue prying. The pliers are much less likely to pop the tube. Once you release the tire, you can see where the inner tube is bunched up. Pull it tight around the rim and inflate it just enough to stay in place.
Replacing the tire is a pain. Press the inner edge of the tire under the edge of the rim and work your way around both sides. It helps to have someone else work with you, but it’s a frustrating job the first time you do it.
What if you pop the tube?
If you pop the tube while working on it, you can buy replacement tubes at most discount stores or bike shops. The diameter and width of the tube are printed on the tire. The new tube will be tighter than your old one, but that’s OK because tubes stretch out over time.
Preventing a crooked valve stem
The way to prevent a crooked valve stem on a bike is to keep the tires aired properly. The stem will stay in place if there’s enough air in the tube. A flat tire causes the tube to bunch up and pull the stem out of its proper place.
If the bike sags at all when you get on it, it’s time to air up the tires.