All the Air Went Out

author : Team BT
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How to Prevent (and Change) Flat Tires

There are few things more frustrating than having a triathlon season marred by flat tires. Sometimes it seems like bad luck, and if it happens again, it's like bad luck that won't go away. 

Early in my triathlon career, I had a summer where it seemed like I could not stop getting flat tires. The upside was that I improved greatly at changing the tubes. The downside was a number of ruined training rides, and a race in which I had two flats in the same race.

Looking back on it, I'm certain it was a single thing that caused all of those flats. The first one may not have been preventable, but all of the ones after that could have been. Read on for how to avoid this repetitive misfortune.

Common reasons for flat tires on bicycles

The most frequent reasons for flat tires are:

  1. Pinch flats caused by low tire pressure.

  2. Punctured tubes caused by, well, punctures.

Pinch Flats

The first one is unlikely to happen unless you have not yet adopted the triathlete's obsessive habit of inflating to 120PSI before each ride. (Give or take, depending on your weight and the road conditions.) If you don't inflate your tires before each ride, or you don't have a floor pump, your tires will become low and when you take a corner or hit a pothole, the tube can move around and end up caught between the rim and the outside of the tire, resulting in the a predictable flat. Imagine taking a barely inflated balloon and smooshing it hard between a metal pen and a hard rubber mat. You might have a slow leak at first, but eventually all of the air will go out.

And triathlon training is expensive, so you might think you don't really need a floor pump. However, the electric pumps used for car tires are not made for the high pressure of road bike tires. Car tires usually have a maximum pressure of 30 or 35 PSI. Bike tires need 110 or 120 PSI. I once burned up an electric air compressor that came with my emergency roadside kit, trying to fill my bike tires with it. Hand pumps will also never achieve the pressure you need. A good manual f floor pump is essential. And it costs less than the number of flats you will endure without one.

Punctured Tubes: Why They are Like Zombies

Punctured tubes are a major cause of flats. It's easy to run over a shard of broken glass on the road or a bike trail. It seems impossible to avoid, and just a matter of luck, but there are steps you can take to diminish the number of times you suffer.

First, if you run over a small shard of glass, it's unlikely to puncture the tube immediately. The hard rubber of your tires (the purple and dark purple in the diagram) is there in part to protect the delicate surface of the tube inside (the pink), which is more like a balloon. Often the sharp item you've picked up on the road won't penetrate through to the inside of the tire right away. If you wear bike gloves with leather palms, every time you finish a ride (or ride through a pile of glass) stop and spin your tires gently while running your gloved palm over them. This will often knock miniscule bits of glass loose before they have time to embed in the tire and work their way through to the inside.

Second, if you ride in areas with a lot of broken glass (kids throwing beer bottles in parks, or unswept roadside bike lanes) you may want to invest in heavier tires, or tires with goop inside that protects the tube.

However, if you just happen to get that freak flat tire, and you have no idea what you even ran over, please remember this: the source of the problem is likely STILL IN YOUR TIRE. Whatever sharp thing caused the problem had to work its way through the tire, and therefore the majority of it is probably still stuck there, protruding through and poking it's nasty sharpness into your inner tube. It's likely you won't be able to see it. If it worked its way through, it's probably cloaked in rubber and dirt. So follow these steps to make sure you don't have a repeat:

  1. When you change the tube or patch the tube, keep the tube and tire lined up. That is to say, don't fling the tire to the side and remove the tube. Figure out where the hole is. (Of course you'll have to do this anyway if you're planning to patch it.)

  2. Once you locate the hole in the tube, you need to find the corresponding area on the tire. So make sure you didn't flip the tire over or otherwise lose track of where the two were lined up while you were riding. This will allow you to find the spot on the tire where the offending item is probably lodged.

  3. Look REALLY hard. If you don't see anything, run your finger gently along the inside of the tire. If you feel something sharp, carefully remove it. If you don't, keep looking because SOMETHING caused the hole, and if you don't find it and remove it, it's just going to poke a hole in your brand new (or patched) tube.

  4. In case the sharp bit of glass or metal flew free when you removed the tire, carefully wipe the inside of the tire. If you are on the side of the road, use your shirt or bike gloves or bandana. Only when you are absolutely sure there is nothing pokey along the inside of the tire should you proceed to replace the tube.

  5. Inflate the tube gently, just enough to give it some shape as you stuff it back into the tire. If you have one side of the tire still in the rim, go all the way around the entire wheel making sure the tube can move freely and isn't stuck. As you put the other side of the tire back on, be gentle. Don't get your tire lever caught on the tube, or let it rub or stretch the tube. After you have the tire back on, and before you inflate the tube fully, go around the entire wheel pressing the tire bead to one side and making sure the tube isn't sticking out into the rim like some sort of rubber hernia. Flip the wheel over and do the same check on the other side.

  6. Once you are sure you're clear, inflate all the way to 110 or 120 PSI and be on your way, confident that your flat was just a bit of bad luck, and not a zombie that will come back to mess up your rides and races for the duration of the season.

How to Change a Tire

Here's a great YouTube video I recommend from Trek. Then you need to practice at least once, if you've never done it before. Practice in your garage or basement, where you can sit comfortably, out of the weather, and take all the time you need. Remember as you are practicing that in real life, you'll be on the side of the road, dirty and sweaty, possibly in a patch of poison ivy, tired, and under some sort of time constraint.


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date: April 29, 2017

Team BT