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5 Causes Of A Recurring Flat Tire

  • By Aaron Hersh
  • Published Nov 20, 2013
  • Updated Feb 9, 2014 at 10:20 PM UTC
Photo: Kurt Hoy

Q:  I keep getting flat tire after flat tire and I can’t really figure out why. Is it just bad luck or is there something wrong with my tire?

A: It’s possible that you keep getting punctures from new sharp things poking through the tire, but that’s unlikely. There’s probably something wrong with your tire, wheel or the way you are putting a new tube into the tire. These are the things that could be causing your recurring flats and how to fix them.

Option 1: Something sharp is stuck in the tire.

The problem: If you don’t remove the object that poked the hole in your first tube, it will probably poke through the replacement tube as well.

The fix: After getting a flat, inspect the outside of the tire for the offending object. Pull out any shards of glass or other sharp things that are stuck in the tire. Next, run your hand along the inside of the tire to check for small items that are poking through. The tire is ready for a new tube once you have removed all the sharp things from it.

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Option 2: Your tire is worn out.

The problem: If the tire rubber is extremely overused, the threads—fibers that make the backbone of the tire—can be exposed. When that happens, the tire is much more susceptible to tearing and puncture. If the casing does tear, flat protection is reduced and the tube can stretch beyond its usual dimensions. Both of these cases can lead to flats.

The fix: A tire is dead once the threads are exposed. Switch it. You will be better off changing the tire well before it gets to that point. Swap your tires when the rubber at the crest starts to crown and looses its round shape. Your rear tire will always wear faster than the front, but swapping them both at the same time is the best practice.

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Option 3: The tube is getting pinched while it is being changed.

The problem: If the tire gets poked with the lever or caught between the tire and the brake track, it can puncture before it is even inflated.

The fix: Inflate the new tube a tiny bit so it holds its round shape before you put it on the wheel. Pass the valve through the valve hole and then press the tube in between the brake track walls so it sits in the wheel. Do not allow any part of the tube to rest outside the brake track while reinstalling the tire. Once the tube is seated in the wheel, use your hands, not a lever, to snap the tire back on the wheel. If you use a lever to lift the tire onto the wheel, the lever itself can swing around and poke a hole in the tube by pinching it against the metal sidewall. Reseating the tire with your hands eliminates that possibility.

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Option 4: Riding with low tire pressure or hitting an object in the road.

The problem: Pinch flats. If you tire is under-inflated and you slam into a pothole or other object in the road, the tire will bottom out against the rim and puncture from the impact between the wheel and the road.

The fix: Inflate your tires regularly. Wide wheels and broad tires can run a lower pressure–down to 80PSI or so depending on rider weight–but standard narrow wheels with 23c tires (check the label) need to be inflated  higher, typically 100PSI or more. And keep an eye on the road. Avoiding potholes and other obstacles is the best way to prevent pinch flats. If an object is unavoidable, lift the front wheel off the road slightly to hop over the object or stand on the pedals and lift your weight off the saddle to use your joints as suspension to absorb the blow.

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Option 5: Rim tape isn’t covering the spoke holes.

The problem: The spoke holes’ sharp metal corners jab against the tube and can cause a puncture if they aren’t completely covered with rim tape. Old rim tape can depress into the spoke holes even if they are completely covered, again creating a sharp edge that can puncture the tube.

The fix: New rim tape goes for about $3 a wheel. Get two new rolls that are wide enough to stretch across the entire tire bed. Lay it flat in the wheel and make sure it covers the spoke holes entirely.

No more flats!

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FILED UNDER: Bike / Gear & Tech

Aaron Hersh

Aaron Hersh

Aaron Hersh is the Senior Tech Editor of Triathlete magazine. To submit a question, write Aaron at Ahersh@competitorgroup.com.

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