How to Change a Flat

By John Wente

If you want to be efficient at changing flat tires, you can learn from watching a pro. After struggling and experimenting with the process for a number of years, I watched a pro in a bike shop do it. I was amazed at how quickly he had the new tube in place, inflated and ready to go. I’ve used this method ever since and found it to be very efficient AND I’ve never pinched a tube using this method.

Before getting into the gory details of changing a flat, there are some tips and details that you need to know.

First, I STRONGLY advise you to coat all new tubes and insides of tire casings with a generous amount of baby powder. Sounds strange, but the powder provides a lubricant that makes it about 50 time easier to get the tire off the rim and put it back on again. Put about two tablespoons of powder into a paper grocery sack (you can still get them at Braum’s) or a gallon size zip-lock bag, unroll the tube, put it in the sack or bag and shake. If the tube will not be used immediately, roll it back up and put it inside a 1-pint freezer zip-lock bag.. Wrap a couple of rubber bands around the bag to make a nice tight package and it’s ready to go into your seat bag or jersey pocket.

For the tire casing, put a generous amount of powder into the casing a rotate it round and round to to distribute the powder. Add more powder as required until the entire inside is coated. If you put in too much, just dump it out.

Second, it is very important to find what caused the flat before installing a new tube. If the offending item is not removed from the tire casing, you’ll be changing another tube perhaps in a matter of minutes. To make it easier to find where the puncture is in the tire, it is important to always install the tire on the rim so that the brand label on the tire lines up with the stem hole on the rim. Then, when you have a puncture, you can locate the hole in the tube and estimate approximately where to look on the tire casing for the puncture.

Finally, it is very important that the rim strip, that thin strip of plastic or cloth inside the rim, completely cover the spoke nipple holes. For some reason (probably $$), wheel makers still use an inferior thin plastic rim strip. If your wheels have these, it’s just a matter of time until you are getting punctures or abrasion from the spoke nipples or nipple holes. Before it’s too late, rip out the cheap rim strip and replace it with Velox or a similar cloth tape. Velox is sold at all good bike shops and it’s quite inexpensive. If the hole in the tube is on the inside (rim side), it’s a sure bet it was caused by either pinching the tube when you installed it, or by a spoke nipple hole. If even the slightest edged of one spoke nipple hole is visible, replace the rim strip.

To change a flat tire:

  1. Deflate the tube completely if it is not already deflated.
  2. Use your tire levers to remove one side of the tire bead from the rim. Be careful not to pinch the tube.
  3. Push the valve stem up though the hole and remove the tube.
  4. Completely remove the tire from the rim.
  5. Inflate the tube until it is about 3-4 times its uninflated diameter and locate the puncture.
  6. Look at the tire in the area that puncture in the tube is located, find the source of the puncture and remove it.
  7. If the puncture was caused by a piece of glass, rock or metal that made a slit in the tire, you may need to install a “boot” to keep the tube from protruding through the slit. Any slit more than about 1/16″ long should be booted. You can make a boot from a folded dollar bill or from a piece of the Tyvek ride number you got on your last “t-shirt ride”. You’ll have to hold the boot in place when you install the tube in the next step.
  8. Inflate the new tube just enough to make it hold its shape and put it inside the tire aligning the valve stem with the tire brand label.
  9. Put the valve stem through the hole in the rim and work one side of tire inside the rim all the way around.
  10. Now begin working the other tire bead into the rim starting at or near the stem and working towards the side away from the stem.
  11. If necessary, let a little of the air out of the tube to ease the job, but don’t completely deflate it–that leads to pinching the tube between the tire and rim.
  12. You should be able to work the bead onto the rim without using tools. If not, you didn’t use enough baby powder. A plastic tire tool should be used to install the tire ONLY as a last resort and then with the greatest care to avoid damaging the tube. It’s FAR better to learn to do it without using a tool.
  13. Once the tire is completely on the rim, inflate the tube about half way and carefully examine the bead all the way around the rim on both sides to make sure it is properly seated.
  14. Once you are sure the tire is properly seated, continue to inflate the tire to your normal riding pressure. Your on-bike pump will probably not have a pressure gage on it, so you should learn to judge tire pressure by squeezing the tire from the sides with your thumb and fingers (not by pressing on it with your palm). If you squeeze the tire every time you inflate it with your floor pump, you’ll soon learn what a properly inflated tire feels like.
  15. Don’t be a litterbug. Even if you don’t plan to repair the tube, take it with you and dispose of it later.

After some practice, you should be able to change a tube in about two minutes unless you forgot the baby powder, then you can count on at least 10 minutes just to get the tire back on the rim.

If the tube is fairly new and not badly damaged, you can repair it and use it again. Here’s a discussion on how to properly patch a tube.