What caused your flat tire?

First, be sure not to miss this important news about Energy Wasting Day.Noah posted his ten quick tips for bike commuters on Monday. Among the tips is learning basic bike maintenance. Among the more common repairs for cyclists is fixing a flat, so it’s good to know what causes flats and how to avoid them.

Pinch flats.

    I got a classic pinch flat last night on my commute home. I was in a hurry and bumped hard against a curb, after which I heard the hiss of a deflating tire. Pinch flats happen when the tube is pinched between a hard object (like a curb or pothole) and the wheel rim. Pinch flats are also called snakebites, because you’ll see two punctures in the tube where it struck the rim. Pinch flats are more common on narrow tires.

You can avoid pinch flats by keeping bicycle tires properly inflated, by riding wider tires, and by avoiding boneheaded moves like bumping curbs and potholes.Road debris. Glass, thorns, nails, bits of wire and other sharp objects can puncture the tire and tube, causing a flat. Watch the road or path in front of you to avoid debris like this, looking far enough ahead so you can maneuver around the debris. Various products are also available offering various degrees of puncture resistance. These include puncture resistant tires, extra thick tubes, plastic strips to shield the tubes, and gooey sealants that go inside the tubes. Whenever you repair a flat, you should always check the tire to ensure the sharp object that punctured your tube isn’t still there.Rim and spokes. If you consistently get mystery punctures in the same spot, it’s probable that your rim tape is worn and needs replacing. The rim tape is a strip of cloth, plastic or rubber that lines the inside of the rim, protecting your tube from the sharp surfaces inside the rim.Blow out. When a portion of the tube sticks out beyond the tire’s casing, it will explode loudly. This can be from incorrect installation or from a damaged tire. You might have cut the tire sidewall, for example, and the tube can herniate out through the cut and blow out with a dramatic bang. As you inflate your tube ensure the tube doesn’t protrude outside of the tire and rim. Also, examine your tires periodically and look for holes or cuts; if you can see daylight through a tire, it’s past time to replace it.Valve damage. Any part of the valve and stem can get damaged through abuse or overuse, through which air can leak. I’ve seen people attempt to apply patches to leaking valve stems, but they rarely hold for long. Sealants don’t typically work well on damaged valves. It’s time for a new tube.Me being me, I’m sure I’ve missed some types of flats. What else should I list? Photo Credit: “Screw you, mysteriously flat tire.” Photo by Wallet B Grundle.

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0 thoughts on “What caused your flat tire?”

  1. Cafn8 says:

    I’ll add that if your brake pads are improperly adjusted and they contact the tire it will not take long for them to cut through the rubber, then through the threads, then through the tube. I found this out many years ago when I was teaching myself to set up cantilever brakes. You’ll hear a PSST—PSST—PSST—PSST sound as the hole passes the offending brake pad. By that time, of course, it’s already too late, and time for a new tire.

  2. Bob LeDrew says:

    Two stories:

    I once had a seagull embed himself in my rear wheel, ending up with his leg being drawn up through the rear derailleur pulleys and flattening my tiire somehow in the bargain. I returned home (almost there anyway) with a wounded and angry seagull flapping lopsidedly off into the distance and a bike covered with gore and feathers.

    A friend was riding in the laurentian mountains north of Montreal. Bright sun and lack of contrast led him to miss a crack running parallel with his wheels on the road, on a VERY steep (15-17%) downhill, while he was flying. He dropped the wheels into the crack, both tires blew… and he didn’t go DOWN. Years later, that non-crash is still legendary among our riding circie.

  3. Fritz says:

    I’ve had to adjust my brake pads to avoid tire rub, so I can see how this can happen. Thanks for that tip.

  4. Justin says:

    It’s good to note that all of these are very avoidable. Since I bought a fairly cheap (24 dollar) floor pump and better tires I haven’t gotten a flat at all.

    It takes some preventative maintenance, like checking your tires’ air pressure once a week (at least), being able to check out where your brakes hit and so on.

    It’s also always worth it to buy the more expensive, perhaps heavier tires because the time and energy spent with their weight is negligible compared to the frustration of changing a flat on the road or walking your bike in a catastrophic tube damage.

  5. geoffrey says:

    I’ve arrived home to find a fish hook in my rear tire and still had no air loss after removing it. Maintaining minimum inflation pressure is obligatory for tube life. That said running 15 – 20 psi is the only way of maintaining any semblance of forward motion in some snow/ice/sand conditions.
    YMMV. Sometimes you have to be willing to accept snakebites.

  6. Matt S. says:

    I’ve never had flats on the road, but I’ve had a few while unhooking the valve from the pump. I think I may need a new pump, like Justin.

  7. Dust says:

    I had a breast cancer awareness pin stuck in my tire last summer.

    I crossed some grass in downtown Chicago to get to the bike path. When I got to the bike path I kept hearing a click with every wheel revolution. I stopped to check my wheel – I figured it was just way out of true or the cones were loose and it was hitting the frame or something. I got back on my bike after inspection and kept riding.

    I kept hearing the click with every revolution. A friend of mine told me to stop and checked my rear wheel, sure enough there was a Breast Cancer Awareness pin stuck into my tire. We had to go past a `not so good area’ of town to get back home – about 2 miles. I rode my bike as much as I could. After awhile the clicks went on to click-PFFFF! click-PFFFF! click-PFFFF! I eventually had to walk about .5 of a mile. Not to bad, scary, but not too bad.

  8. doug says:

    once a tube split along the seam. at 7:30 in the morning. in the rain. on the way to work. on my first day.

    lesson learned: always, always ALWAYS have a spare tube. no matter what.

    another good lesson is to get heavy, expensive kevlar-armored tires. my gatorskins are quite nice. just the other day i blundered into a patch of broken bottle glass. i didn’t realize it, however, until i heard the crunch of my tires crushing a large chunk of green beer bottle. no flat.

    another fun story: last week i topped off my rear tube, but when i pulled the pump head off the valve top popped off with it. however, the pin was locked, so no air was leaking out of the valve. since i was on my way to work i just hopped on and rode in. a week later and i still haven’t had to replace the tube. unfortunately, it won’t be long until i have to top it off again …

  9. Hilton Meyer says:

    I was getting snakebites on a regular basis last summer and eventually converted to a tubeless system. Basically you take a 20″ inner tube, split it in half and then replace the tire. Just before completely popping on the tire you put in some sealant and then inflate. The inner tube will be sticking out along the edge and then you take a box cutter and carefully remove the excess. The great thing is that I got a pucture the other day, well sort of. I heard the PSSSSS starting and then after a few revolutions it just went away and I carried on riding no hassle. Highly recommended to anyone.

  10. Mike says:

    It’s also easier to get flats from road debris during the wet as the water acts like a lubricant in aiding objects to puncture tires.

  11. Mark Layton says:

    When the bike goes on the stand for weekly cleaning and maintenance, I always go around the tire looking for holes and slits. I use an old ice pick with a rounded-off tip to gently probe the hole. Frequently get a small piece of glass out. Figure if its allowed to stay in there, that tiny piece of glass will eventually work through the kevlar belt and into the tube.

  12. 2whls3spds says:

    My latest scourge has been the broken lane marking reflectors, they are plastic and have sharp edges, I lost an almost new tire to one this past week, slashed the sidewall 🙁


  13. jjange68 says:

    I get the good ol’ valve stem cracks. I had one today it is such a pain in the A$% when you just want to get home. It’ still better than $4 a gallon.

  14. Omegaman60 says:

    Has anyone experienced a tire blow out while your bike was parked during the day. I rode in okay and my tires were fine. Ten hours later, I came out and found my front tire blown off the rim. The ride in the morning was in the fifties but the temperature spiked up to high eighties in the day. I keep my tire pressures at max to avoid pinch failures. This tube and tire had been on for at least 25 rides and over 300 miles. What could have caused the tire to rupture.

  15. soysos says:

    a spare tube does no good if your mini pump sucks. I had an incident just a couple days ago where I hit a pothole and lost my tire. 20mm tires will go flat very very easily I have found. so I carry a spare and a mini pump. anyway I went to change my tube and got as far as airing it up when I went to release the pump apparently the force on the pump had snapped the head off my valve. it seemed to be holding pressure so I decided to ride on. I made it one block and had to walk the 6 miles back home.

  16. MattS says:

    I’ve now had this happen three times. A sudden, total loss of air, which seems as if it must be a blowout, but when re-inflated, the tire is fine and holds air as well as it ever did. It most recently happened this week, after my son had borrowed the new bike, returned on it seemingly riding fine, then woke to a complete flat.
    I would blame merry pranksters, but the bikes are kept in the apartment. The first two times this happened I took the tube out before re-inflating and put it in the tub, no air bubbles. I put the tubes back on, and they lasted months. Any ideas what is happening? I have two theories, but one is bad magic…

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