How to fix a crooked valve stem on a bike

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

fix a crooked valve stem on a bike
A crooked valve stem can keep you from airing up your tire. Sometimes you can fix it by deflating the tire until it lets you pull the stem back through. To prevent it, keep your tire aired properly.

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.

One thought on “How to fix a crooked valve stem on a bike

  • April 16, 2019 at 11:49 pm
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    Regarding the use of a screwdriver to remove the tire…you *can*, but pretty much any bike shop or repair kit will offer a set of tire levers (inexpensive, typically a set of three) designed for the task. They don’t have the sharp corners of a screwdriver (that may damage the tube), and they typically have hooks on the opposite end that can be hooked on a spoke so you can use more than one lever at a time. The levers are small & and easily carried with you while cycling. The need for the levers is greater on a narrow high-pressure tire, fat tires like BMX or mountain bikes aren’t usually quite as difficult to mount & unmount.

    Also recommended: Partially inflate the tube, enough so it takes shape but before inflating to high pressure. Work your way around the tire, squeezing the tire beads to make sure that the tube is seated nicely inside the tire without being twisted or pinched between the bead and the wheel’s rim. If the tube is pinched, when fully inflated you can get a blowout, often with two characteristic “snake bite” holes.

    Reply

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