The life of a Dad who strives to be the best dad possible

Fixing Flat Bike Tires

Fixing bike flats

Hmmmm, this sucks.

Yesterday, I had my longest ride of the year at four hours.  The day was flat-out spectacular.  The late “winter” day in Arizona afforded me pleasantly cool and sunny conditions.  I kept remarking how fantastic the day was for riding.  Physically, I felt awesome even though I was at the end of a three-week Base 2 cycle.  Sure my legs had a little latent fatigue, but overall, they were responsive and steady.  Thanks to temperatures in the low-60s, I never got too hot or cold.  That also made nutrition a snap, requiring only two stops: one to peel off extra layers and one to replenish my single water bottle.  I mean, the day was just ideal and, while I started to tire in the fourth hour, had I been fresh, I am certain I would have wanted to continue riding.  There was, however, one small nagging annoyance: Debris.

For whatever reason, I kept seeing debris everywhere.  Twigs, branches, leaves, and just stuff seemed to inhabit every bike lane I found.  For those that don’t live in the desert, let me give you a quick education.  Here in the Sonoran Desert, everything has thorns.  Given the scarcity of water, all the local flora has adapted various defenses against being eaten and this almost always includes thorns.  Not really a big deal, usually, but they can ruin a perfectly good ride.  Just like the one I was having.  Now, normally, I wouldn’t even pay any attention to it but on this day, I was riding alone and had my usual repair kit, which contains only one spare tube.  Not the best feeling when you are repeatedly finding “stuff” on your bike journey.  I am more than confident in my ability to fix a flat tire but I can only change a flat tire if I have a spare tube to use.  (Side note, I actually didn’t even get a flat.  I did, though, find it pretty comical that even on the best of days, there’s always something.  This time, it was concern over getting multiple flats since this can be a problem on long rides in Arizona.)

This small, but legitimate, concern reminded me of the very first bike ride I did in March 2009.  I had just purchased my first tri-bike and was headed out with two buddies.  Literally, in less than a half-a-mile, I had a flat.  I pulled over, looked at my back flat tire, and quickly realized I had NO CLUE how to change a flat bike tire, much less one on my pretty, sleek triathlon bike.  Pretty embarrassing actually.  Thankfully, one of my friends gave me a quick lesson, for which I was extremely grateful, and shortly later, away we went.  Later on the same ride, Karma and Fate jointly conspired against me and gave me a chance to apply my new knowledge.  Yes, a second flat tire. Ah, the joys of thorns…  This time however, I worked solo and was successful except I had to borrow a tube since my spare had already been used to fix the earlier flat tire.

All that leads to the two points of this post: One, if you are riding (a) solo and (b) longer than two hours, carry extra flat tire repair gear.  A small bit of extra weight might prove needed.  And, Two, I thought I’d give a quick tutorial on how to fix a flat tire.  I hope this helps those that are unfamiliar with fixing flat tires or just plain intimidated by it.  Changing a flat tire is pretty easy and can be done by anyone, so don’t worry.

The Parts

1.  The Inflator: This is the device that attaches your CO2 cartridge to the tire valve.  There are two basics kinds: those with flow-control and those without.  You can see examples of each on the picture.  While the flow-control options are larger and thus heavier, I strongly prefer them.  Having that little start/stop lever can be critical AND prevent you from making the tiny, but crucial, mistake of releasing the compressed CO2 too early.  Without the lever, it is a one-time chance.  Get it wrong and you’ll be sorry.  One other bonus, I prefer to carry and extra CO2 cartridge in my repair bag.  Most of the flow-control versions will house a CO2 cartridge, making the extra size much less wasteful.

2.  CO2 Cartridges: This is the canister holding the compressed CO2 to inflate the new tube.  They are either threaded or non-threaded.  You can see the difference in the picture.  The non-threaded versions cost pennies less but work the same.  Also, there’s sizes: usually 12g or 16g.  (You may see 25g but they are less common.)  If used correctly, the 12g will provide up to 90PSI, the 16g will provide 90-120PSI, and the 25g will provide up to 170PSI.  My advice is get the 16g version.  That’s enough CO2 to fix your flat tire enough to finish the race or ride.  The 12g version might leave your tire somewhat “squishy”, dramatically increasing the potential for a repeat flat tire.  For our purposes, 25g is overkill and, if fully used, can easily cause a blowout from overinflation.  One final note about CO2 cartridges, make certain that your CO2 cartridges and inflator are compatible.  Some inflators only use threaded (and vice-versa), so double check.  Most of the flow-control inflators can use either, another reason I prefer them.

Make sure your CO2 cartridges will work with your inflator!

3.  Tire Irons: These are the devices used to remove the tire from the wheel, enabling you access to the flat tire (or really, flat tube) to change the tube.  Be aware, not all are created equal here.  If you purchase a “Flat Tire” package, often the tire irons are garbage and will bend on the first use.  Get decent ones (typically meaning they have a metal core for extra stiffness).

4.  Lastly, Repair Bag: While this is obviously not a tool you need, you have to carry all this stuff.  You have a world of options for this, but, for the repeat readers here, you already know I follow a “less is more” philosophy.  So, I prefer the smallest bag that will hold what I need.  As you can see from the picture, the small one fits nicely under my saddle and easily holds all my stuff.  If you opt for a larger bag, you can carry more “stuff” but that’s just adding unnecessary weight to your bike, something I avoid like the plague.

All that in one bag???  Yes.

All that in one bag??? Yes.

Now to the actual changing of your flat tire… PPPPSSSSSSSSSsssssssssss….. you have a flat tire, ah crap.  Whether at a race or at home, the process remains the same:

1.  Release the remaining air from the flat tire (or flat tube).  Gotta do this to remove the tire from the wheels.  Then, remove ONE SIDE of the tire.  This will enable you to remove the flat tube and save you time and headache when compared to removing the whole tire.

2.  Check the exterior AND interior of the tire for pieces of glass, thorns, and other undesirables.  Nothing good about getting 50 feet down the road and having another flat tire while still being 50 miles away from your car and having no more spare tubes.  That’s a Big Buzzkill.

3.  Get a bit of air into the spare you intend to use.  Now, there’s two ways to do this: The Right and The Wrong way.  Please make the correct decision.  The Wrong way is to waste a CO2 cartridge, over or under inflate it, and/or risk a blowout.  Don’t be That Guy (or Girl).  The Right way is to use your mouth.  Seriously.  Don’t get all freaked out and become a germ-a-phobe.  Just open the valve, put your mouth over the valve, and partially inflate the tire using your lungs.  This works perfectly.  Plus, there’s a range of inflated-ness you want; enough to remove any creases but not enough to prevent you from changing the flat or causing a “pinch-flat”.  If you purchased a flow-control inflator, you can use that.

No, it is NOT gross....

No, it is NOT gross….

4.  Put the very-slightly inflated new tube into the tire and carefully reinstall the side of the tire you removed.  This is certainly more art than science and practice will make perfect.  You don’t need to use the tire irons to do this.  Just proceed slowly and don’t try to force it.

5.  So, the new tube is in the tire and it is time to inflate.  At this point, I am hoping you purchased the flow-control option as it makes this way easier.  If you didn’t, (a) open the valve, (b) get the inflator on the opened valve, and (3) carefully screw in the CO2 cartridge.  This is really not that tough, but even the pros make mistakes.  For example, check out 1:30 of this video for the great Chrissie Wellington potentially blowing her chance in the Ironman World Championships in Kona in 2008.  If you purchased the flow-control version, install the CO2, put the inflator on the open valve, and inflate.  Boom, it is that easy.

6.  Now, you have a newly-inflated tire.  Well done!  At this point, before you put it back on your bike, check the tire for any bumps or other irregularities.  You want it to be smooth and clean.  Bumps or other deformities can be an indication of a potential pinch, which will almost always lead to a second flat tire in little time.  That equals Not Fun.  Once you have verified the tire is good, put it back on your bike and you are ready to roll!

Please be certain to take with you all the tools, stuff, and garbage you used.  I despise the people who view our world as their garbage can.  Please don’t ever do that.  If you do this in a race, you might even get a penalty.  Litterbugs aren’t cool.


  • There you have it.  The quick and easy way to fix a flat tire.  Here’s the short and sweet:
  • Remove flat tire and tube
  • check tire
  • very slightly inflate spare tube
  • get new tube and tire reinstalled
  • check for cleanliness
  • reinflate
  • check again for clean lines and random bumps
  • clean up your workspace

I would highly recommend practicing this at home a few times before you ride.  As I mentioned above, I was the lucky recipient and my friend’s good nature and have paid that forward more than a few times over the years.  I have no issue helping others in need but you don’t want to be stuck for hours if a Good Samaritan fails to arrive promptly.

Lastly… as soon as you get home, deflate that fixed tire and re-inflate with your bike pump.  Why do I need to do this, you may be wondering?  Well, about half of that CO2 will leak out of your tire in less than 24 hours.  You want your tires inflated with compressed air, not compressed CO2.  If you don’t want to trust me on this one, just Google “Ideal Gas Law” and have some fun dorking out.  (Disclosure, I am a dork and did read various articles on this.  Yes, I am That Guy and have always been so.)

That’s all!  I greatly appreciate comments and/or questions, so please don’t be shy below!  I hope that was helpful, happy riding, and thanks for reading!

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