How to use CO2 for cycling – a beginners guide

So perhaps you were like me – afraid of the little cylinder.  Perhaps you thought it would just simply explode on you, or that when you went to use it you’d end up putting more CO2 into the the sky than into your tube.  Or perhaps you’ve just been perfectly content with pumping up your tube while sitting on the side of the road cursing whatever it was that just flatted you.

Whatever the reason is, it’s time to get over that fear of CO2 and start making your life much easier.

The parts:

First up, let’s talk about the pieces.  A ‘proper’ CO2 setup has two pieces – the inflator (aka nozzle) and the cartridge.  Here’s the inflators:

IMG_8030 1280 x 853

(With flow control lever on left, without on right)

Inflators come in two basic flavors.  Those without flow control (ability to stop the pressure) and those with flow control.  Obviously the pro to flow control is that you can stop/start it once you pop the seal on the cartridge.  The con is they cost a bit more (although, as of this writing the flow control ones are on sale for less than those without).  If you don’t have flow control – it’s sorta a one-shot deal.  You either do it right all at once the first time, or you’re down and out a cartridge.  Hint: Buy the one with the flow control.  (Though technically you can control the non-flow control type by carefully tightening and un-tightening the cartridge from the inflator, seems a bit tricky and a bit risky)

Cartridges come in different sizes – 12g, 16g or 25g.  The smaller ones are designed for filling tires up to about 90 PSI.  The larger ones are designed for filling tires up to 120+ PSI.  This corresponds to lower pressure tubes such as clinchers (typically 90-120PSI) and tubular’s (140-170 PSI) such as race wheels.

There are also two different types of cartridges – threaded and non threaded.

IMG_8029 1280 x 672

(Non-threaded on top, threaded on bottom)

What’s the difference?  Well, simplicity (and a patent).  The threaded ones you have a lower likelihood of screwing up, so I just use those.  They only cost a few cents more.  Make sure that if you buy a inflator and cartridges not in a little kit that you buy matching ones (threaded with threaded, and/or non-threaded with non-threaded).

Last but not least – think about how you want to carry the cartridges.  If you have a seat bag, make sure you have room in there.  If you have a tail system on your tri-bike you may be able to fashion something creative or purchase something.  I actually use the bag that came with the little kit and found it fits PERFECTLY into my Hydrotail.  From there, I just created a little zip-tie loop that connects to my Velcro straps for my extra tube.  Works awesome!

image

(Note: If you get this kit like I have, toss the tire levers, they are garbage and will actually bend on their first use)

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(Above: Side view of little bag inside Hydrotail, contains two tire levers, two cartridges, one valve/nozzle, and a bike wrench set.  Below: Same thing view from above seat)

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Ok, easy so far?  Good.  Now let’s get onto the action.

Putting the pressure on

Ok, so after you’ve deflated your tire (after wandering through the roadside gravel while distracted in a race by that ‘nice…something’ that just passed you from the M/F 20-29 age group) – it’s time to get air back into the tube.

The first part is no different than your normal tube changing procedure:

  1. Release any remaining air out of bad tube (or tubular)
  2. Check the tube and/or tire to figure out if something is embedded.  Nothing worse than flatting a mile down the road again because a piece of glass is stuck in the tire.
  3. Get the new tube with a touch of air in it* situated below the tire and onto the rim.

*Ok, now comes the change from usual.  At this junction we need to get a bit of air into the tire to form it onto the rim.  There are two ways to accomplish this.  The right way…and the wrong way.  Let’s start with the wrong way.

  1. [The right way] – If you have an inflator that has flow control, then put just a tiny bit of air into it – a split second at most.  Just enough to create a circular form.

However, if you didn’t buy a flow control unit – then using that nifty thing otherwise known as your mouth and tongue – press the top of the valve stem and blow a bit of air into it.  It’s really not that hard.  Seriously – try it.  Go now into your pile of dead or new tubes and try it.  You’ll note it inflates near instantly enough to form a tube like object.

  • [The wrong way] – Taking one of your two cartridges and holding it onto the tube valve for a few seconds and then yanking it off the valve while the cartridge releases the remainder of the gas into the air.  This is the wrong way because now you’ve just wasted a cartridge and didn’t get any air into the tube with the first cartridge now requiring you to use your second cartridge.  Murphy’s law dictates that should you do this, you’ll likely flat again exactly 500 yards down the road …and be 55 miles from your car…without any further way to inflate.

 

IMG_8038 1280 x 853

(Yes, I blew this one up using just my mouth with tongue depressing the valve, it just takes a few seconds)

So – we’ve got things to the point where the tube is inside the tire, and the tire and tube are roughly on the rim.  Now, let’s get it all ‘cleaned up’ and ensure there aren’t any edges sticking out or other funkiness.  Clean lines all the way around, no bumps or unevenness.

IMG_8040 1280 x 853

Blast off

Now that everything is ready for launch, let’s first do a Hail Mary.  With that out of the way – it’s time to hope for the best.

First step: If you don’t have a control valve – then take the inflator and attach it to your tube’s valve first.  DO NOT attach it to the cartridge first (unless you have a control valve).  You can certainly do this, but this increases the likelihood of premature ejection of your little friends valuable contents (just sayin’….).

Second Step: With the nozzle on the tube valve and ready to add air, it’s time to screw in the cartridge.  It should screw in easily at first, and then come to a slight halt.  It’s at this juncture that you will break the seal on the cartridge and release the CO2 into the wheel.

IMG_8042 1280 x 853

Once you do this – it will inflate your tire in about 1.5 seconds.  It’s quick.  Very quick.

Depending on if you have a higher pressure tire (such as a race wheel), you may need to do one more cartridge to get to full pressure.  Remember that riding a low pressure wheel will likely only get you a flat again – so be sure to really get as much pressure as you can without exceeding the limits of the tube/tire.

With everything complete – inspect the tire.  Make sure everything is still ‘clean’ – good even lines all the way around.  You don’t want to flat a few yards down the road because of an uneven tire.

Pack up your little roadside work zone – cartridges, tubes, Dunkin Doughnuts leftovers, etc… and take it with you.  Don’t be the cyclist who leaves their junk lying around.  Plus, if you do leave stuff behind it will get you a well deserved penalty on the race course.

Wrap up

So there ya go – that’s all there is to it.  I know I made it sound really long, but in reality it’s very quick.  When you do it for real it will only take about 2-5 minutes tops end to end – even less if you really practice it.  Here’s the 10 step version for you:

  1. Undo old tire
  2. Check old tire for intrusion
  3. Blow small amount of air into tube to form tire
  4. Get new tire situated on rim and under wheel
  5. Validate clean lines
  6. Attach inflator nozzle to tube valve
  7. Attach cartridge to nozzle and tighten to pop seal
  8. Tire inflates…use another cartridge if on high psi wheels
  9. Check tire for ‘clean lines’ and no bumps
  10. Clean up mess …finish ride.

But WAIT!!!!!

Now – one last REALLY IMPORTANT STEP!  When you get home, you MUST deflate your tire out and refill it with regular air (just using a simple stand pump).  CO2 as a gas quickly dissipates through the rubber and you’ll lose about half of your PSI by the next day.  Here’s a post that explains it all really well in scientific terms.  Just trust me on this – I learned this first hand as well. ;)

IMG_8048 1280 x 853

That’s it – there ya go!  Now go buy yourself a little CO2 kit and save yourself the hassle of a pump on the frame.

Tags:

50 Comments

  1. Nice CO2 guide Ray. Weight is less of a concern to me so I'll probably stick to my pump, but I've been curious about this inflation method and appreciate this info.

    Reply
  2. Oh my God, I totally needed that lesson (although I could have done with it two weeks ago). Picture Danielle on the side of the road on RAGBRAI thinking she is badass for changing her own tire (and her back tire to boot) despite the multitude of people who offered to help. Gets ready to inject the air and then hesitates... "Wait, how do I just put a little bit of air in my tire to get it back on and then inflate it all the way?" (I didn't even know they had flow control ones) I was perplexed. It never occurred to me you could blow up your tire with your mouth. And eventually a guy saw me staring at my CO2 cartridge confusedly and stopped and used his little pump to fill my tire.

    Damsel in Distress 1
    Badass 0

    Reply
  3. Oh, fantastic post! I've been wondering about CO2 cartidges. I still need help on the general changing a tire thing though because I blew up a tube last night while trying to inflate it. Scared the bejeezus out of me, so I'm off to the bike shop to get them to show me how it is done...

    Reply
  4. Hahaha this made me laugh considering I JUST posted about my pumping troubles.

    Reply
  5. Ray, this post was great. I tried my CO2 cartridge a couple of months ago, just because I had never used one before.

    I did not think to blow up the tube a bit via my mouth and will give that a try. I also did not know about the need to refill once I got back home after using the CO2.

    Thanks - great info and a terrific read with, as always, excellent photos.

    Reply
  6. Liz

    I learned the tip about blowing into the tube from the bike tech when I bought my bike. He made the whole thing look easy.

    The first time I tried to fix a flat I was home visiting my parents so my Dad "helped." He snapped a lever and I got so frustrated that I stormed off.

    I don't even remember how the new tube got on the bike.

    I can finally do it, but it takes me about 20 minutes and I need a nap afterwards. I pretty much just pray to the triathlon gods that I don't get a flat in a race.

    Reply
  7. Nat

    Ohhh! Perfect timing. I just got C02 last weekend and kind of new how to use it but not really. You always have such great tips! Thank you!

    Reply
  8. That was great, Ray! Thankfully I had already made all my mistakes and am somewhat skilled in using the darn things, but I still get a little scared about screwing it up every time.

    I like to use the full cartridge holder, only because it doesn't turn so cold on my hands. I had one similar to yours and the first time I used it I screwed it up because I was like "OH MY GOD IT'S COLD!" and I let go of it thinking it was going to blow up my hand or something. :)

    GREAT instructions!

    Reply
  9. SLB

    Great post, learn something new every day as they say and I did about the the need to refill on the hand pump! Who knew...well obviously you did, thanks again.

    Reply
  10. "Cartridges come in different sizes – 12g, 16g or 25g. The smaller ones are designed for filling tires up to about 90 PSI. The larger ones are designed for filling tires up to 120+ PSI. This corresponds to lower pressure tubes such as clinchers (typically 90-120PSI) and tubular's (140-170 PSI) such as race wheels."
    This is like an SAT question.
    If biker A leave Skyline at 10am and biker B leaves DC at 11 am, but biker A has aerobars ...

    Reply
  11. Bob

    Good stuff...hey, I changed my blog address, FYI, to
    link to kim-bobl.blogspot.com

    Now using plain "Bob" instead of Tribob.

    Reply
  12. Excellent post, professor. I love using the CO2s also, but there was a definite transition period of wasting a lot of cartridges. Now I love them, and I spend way more time getting the dang wheel back on the frame than I do pumping air.

    2 questions: where do you buy cartridges? I've found a big discrepancy in prices from shop to shop. Also - what kind of irons do you use to get the wheel off and on the rim?

    Reply
    • booker replied

      Amazon or Wally World (look in the sports section, near the air guns). They're dirt cheap if you buy a box, just be sure to get the right type for your nozzle (threaded or non-threaded). Go for a generic brand and save money, they're the exact same thing as the fancy-labeled ones marketed to cyclists for twice as much.

      Reply
    • Mark replied

      Yes, check Amazon. For box of 6 cartridges. Cheaper than LBS.

      Reply
  13. Did you write this specifically for ME?! I KNOW you did! after i blew the first cartridge (SO smart to attach the nozzle FIRST, then the cartridge, duhhhhh), i gave up and called for a ride.

    i'm not so much down with the blowing the tube up with my mouth though. that is seriously badass. but only if people see you doing it.

    Reply
  14. i've been using co2 cartridges for a few months now and love 'em. now that i've really figured out how to change a tire quickly i think the weight factor and speed definitely makes it worth it.

    since i bought those continentals i've ridden about 100 miles and no flats. thanks for the recommendation!

    Reply
  15. I would also like to add something.

    If you are using a disc wheel in a race, make sure that your fill device fits in the slot!

    I made this rookie mistake ONCE.

    I was leading the race and all I could do is stand on the side of the road and watch everyone go by.

    I had a device like the one
    pictured on the left. A microinflate is what you need.

    Reply
  16. bv

    Ooooh what rear hydration frame is that, though I recognise the Tacx Taos.

    Reply
  17. It's the HydroTail H.5 - I wrote up a whole post on the setup here with all the deets:

    link to dcrainmaker.blogspot.com

    Note, after considerable time, I've decided that the Tacx cages suck though - they snap off way too easily. That said, if you simply replacethe upper screw with a waster and screw, life is grand and they'll never snap.

    Reply
  18. Eli

    Just one complaint where you say:
    Depending on if you have a higher pressure tire (such as a race wheel), you may need to do one more cartridge to get to full pressure. Remember that riding a low pressure wheel will likely only get you a flat again – so be sure to really get as much pressure as you can without exceeding the limits of the tube/tire.

    To me that seems to be recommending people overinflate their tire instead of using the correct pressure. So really you should aim for 15% drop which means you need to factor in tire width and your weight which in general means you're no where near the limits of the tire. I realize its hard to tell pressure with a CO2 cartridge so its generally better to go over but that still should be the aim.

    I generally do group rides so use a road morph pump. (the only one I've found so far that can get to a high psi easily and it has a nice pressure guage) That way if someone in the group needs help I don't have to worry that I'm screwing myself.

    Reply
  19. Hi Eli!

    Thanks for dropping by!

    My comment was specifically referring to race tires that have PSI at 170 - such as many tubulars. For example, a typical cartridge will only get you to either 90 or 120. But that's almost half what a typical race tire needs, and would be very unstable on corners/descents.

    But in general I agree, over-inflating is just as bad as underinflating. It's important to know what your tires will need and be able to judge accordingly.

    Reply
  20. Eli

    I've just met too many people who think the pressure rating on the outside of the tire is the recommended tire pressure when its really just the max the tire can handle. Since most people I meet use clinchers and some of them are racers who think the higher pressure gives them an advantage.

    Going by this tubulars shouldn't be inflated so high either:
    link to adventurecycling.org

    link to cyclingcrowd.com

    Reply
  21. According to the instructions on the side of my CO2 carts, they recommend using them in the vertical position to get the maximum gas out. No idea why that would be, but thought I'd share...

    Reply
    • booker replied

      Because CO2 is heavier than air and flows down, not up. Orienting it vertically allows more air to get into the tire, especially as it becomes quite cold near the end due to the laws of thermodynamics.

      Reply
  22. Flo

    Just wanted to add that there are also nozzles without an extra flow control lever per sei, but still provide flow control by means of turning the cartridge. After installing the (threaded) cartridge, the seal is popped, but flow is blocked. You then have to screw it back out of the thread ever so slightly to release the CO2. If you turn it back in, CO2-flow stops again...

    Reply
  23. Efraim Shaw

    Does the Little Kit from Peformance come with a flow control valve?
    Thanks!

    Reply
    • Rainmaker replied

      No, unfortunately not. At least, not the variant I picked up years ago.

      Reply
  24. Dave H

    If you are using Innovation Micro Inflate all you need to do to control the flow of CO2 is screw the canister all the way tight and then back off the canister a little at a time to inflate the tire or tube, you can use as little air as you want. I use and sell these all the time, they work great.

    Reply
  25. Mike

    HEY I've been wondering - usually a CO2 cartridge takes all the canister, but I had a low tire and used it - with a control valve - and now wonder - it it done for, or can I reuse it? I'm guessing it's a one time thing, since it has a specific pressure ....

    Reply
    • Rainmaker replied

      I'm betting not. Given the high pressure, I'd bet that it won't take very long (a couple hours?) for the remainder to slowly seep out through the nozzle.

      Reply
    • booker replied

      Take a trick from pellet guns and put a very small smear of grease on a cartridge before you insert it, so the nozzle side becomes lubricated. This creates a very good seal and will likely allow your partially-spent cartridge to retain pressure for weeks if not months.

      Reply
  26. Sam Brasel

    I'm a big fan of CO2 and the members of my group are slowly, grudgingly moving over to them.

    I would add a step #3.5: After filling the tube with a bit of air, carefully CLOSE THE TUBE VALVE. My experience is that the tiny bit of pressure in the tube at this point is insufficient for a Presta valve to reliably remain closed.

    Regarding which CO2 cartridge size to use, for typical recreational road cyclists with 23mm tires I would never use the 12g cartridges, and when the air temperature is the least bit cool--say, below 70 degrees F--I recommend the 20g cartridges to avoid a subsequent pinch flat from inadequate tube pressure. They can cost 3 times as much as the threaded 16g cartridges but they're worth it.

    Reply
  27. Naomi

    I know this is a relatively older post, but I wanted to let you know that I did find it very useful. Racing my first 70.3 this weekend and I had been asking myself about carrying CO2 with me "just in case". So your post was very informative and helped me make up my mind. Thanks!

    Reply
  28. allan

    Thanks for the helpful site. Bought a road bike 4 months ago and have not had a flat tire (YET!!). Bought all the cartridges, control valve and levers, and now am awaiting my first roadside flat. Thought i would research the procedure ahead of the inevitable.
    Al Barry

    Reply
  29. Trisc

    Can't believe you omitted critical safety advice! Protect your hand from the intense cold as the cartridge depressurises. Its actually possible for your skin to stick to the cartridge and come away if you pull it off. I've seen it happen, so always use a cartridge sleeve or similar.

    Reply
  30. Sam Westhead

    Hiya Ray,

    As per Naomi I know this is an old post now but CO2 hasn't changed much in the past 13 billion years so there's no harm in making a few more comments.

    Have you had any problems with the cooling effect of the CO2 expanding as it leaves the cylinder? Apart from freezing the tips of my digits (countered these days by foam or neoprene cylinder sleeves) I've had one or two occasions where the rubber/latex/butyl around the valve has frozen and snapped during the inflation process. Which has made me dubious about CO2 inflators, though i still carry them on all rides and races. Ever encountered this?

    Thank you in advance

    Sam

    Reply
    • Rainmaker replied

      I definitely haven't seen that. My single biggest issues in CO2 is A) TSA taking them away from me B) Remembering to grab threaded and not non-threaded.

      Reply
  31. Jason G

    Very useful post! I just fell for neglecting that final step after using CO2 for the first time and took the bike to the shop to see if I had a hole in the tire that re-punctured the next tube. Doh! Fortunately they didn't charge me anyway, but now I know.

    So for a 25mm tire, am I looking to use a 12g or 16g cartridge? I'm thinking the latter is probably best but ended up buying a mix of them without thinking.

    Thanks again for writing this post.

    Reply
  32. What are your thoughts on using Tire Sealant instead of tubes and CO2?
    link to competitivecyclist.com
    link to triradar.com
    link to youtube.com

    Reply
    • Rainmaker replied

      I know a number of folks that do, primarily during races. For me though, the CO2 is a quick and known thing - and more importantly, when I travel with my bike and TSA takes my CO2, it's cheap to replace. ;)

      Reply
    • Kenny Roberts replied

      Sealant such as Vittoria's Pitstop is only option in shorter Triathlon races (Olympic or sprint ) for bikes using tubular tyres as putting on a spare tyre is too much time and stress for average Joe.But Co2 is still needed to top up if Pitstop does not inflate hard enough.Watch YouTube for info on Pitstop use.

      Reply
  33. DonC

    Stumbled upon this while surfing your site. Very informative and timely considering I'm looking to ditch my pump in favor of CO2 cartridges. I see this is an older write up. In the automotive world Nitrogen is the preferred gas for tires, as N is a larger molecule than O2 (and CO2). Has the cycling world moved, or considered the move to N?

    Reply
  34. David

    Same. Stumbled upon this while surfing your site :-)
    And I also experienced the CO2 "deflation phase" by myself. Actually, I lost (read sent to the trash) some tubes I believed were flat after using a CO2 cartridge and waiting for 1 or 2 days, angry at myself that I couldn't change a tube properly :-)))
    Last weekend, I pumped the old way a deflated tube (originally inflated with a CO2 cartridge) and it stayed inflated.
    That's what I call experience :-) ... confirmed by theory, thanks to your link ;-)
    So now: new tube => C02 => deflate => pump

    Reply
  35. Jens

    One more tip regarding rear wheel tier repairs - Not really specific to CO2 but anyway:
    Make sure your chain is shifted to the smallest chainring both on the front (crank chainrings) and the back (cassette/socket).
    This makes it a lot easier and faster to get the rear wheel on/off the bike and will save you time and most likely grease/dirt on your hands trying to get the wheel back on without the chain getting stuck :-)

    PS ! If you are lucky enough that you brake has a "release mechanism" make sure to use it as this will further help you getting the wheel ofte/back on. Unfortunately many Tri bikes does not have this otherwise very convenient feature/functionality :-(

    Reply
  36. Roofi

    Tip when handling another persons CO2 inflator. NEVER, I repeat *NEVER* assume a cartridge screwed into a nozzle has been used.

    The damage caused by a very high velocity cartridge being ejected from a nozzle has to be seen to be believed......

    Reply
  37. Dan Johnson

    Nice post...great write up. I've used CO2 for years, but didn't know it dissipated quickly after inflation. No wonder..... Thanks

    Reply
  38. Matt

    I'm still slightly puzzled as to which size cartridge I would need. Currently I'm riding an entry level road bike on 110 psi. Which size would I need, 16g or 25g?
    Thanks in advance

    Reply
    • Rainmaker replied

      16G is normally good to about 90PSI, which is fine in most situations post-flat. However 25G will get you all the way to 110 - and have some leftover in case you need to top-up (such as developing/finding a secondary slow-leak). I always buy the bigger ones if I can.

      Reply
    • Matt replied

      Thankyou for the response, that's made it alot clearer. Great review by the way. Not bought any yet but can't wait to give one a go

      Reply

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