# Is a 16 grams CO2 cartridge enough to inflate a 29" mountainbike

I used to ride a 26" mtb, but now I'm switching to a 29er. Since the volume of the tire increases, I was wondering is one 16 gram CO2 cartridge enough to inflate the tire?

Notes: The tire will be between 2.1 and 2.25 wide. Since I'm big (110 kg) I need more pressure than a lower-weight rider.

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Thanks for the chart link, it doesn't give me the answer I was looking for but it come close. – Geoffrey Nov 25 '15 at 7:56
Why do you run your tires so high? I run my tires on my bike at ~21 psi – Luke Dec 21 '15 at 1:50
If I use only 21 psi, I get snakebites. Recommended for Nobby-Nick 2.25 is 26-54 psi (schwalbe.com/en/offroad-reader/nobby-nic.html). – GvS Dec 21 '15 at 11:11

Yes. One 16 gram cartridge is enough to fill an average 29" tire. I just tested in my Schwalbe Rocket Ron 29x2.25, and from empty it gets to about 38 psi. I run tubeless, so normal pressure at my 110kg weight is around 35-38psi.

With a tubed setup, 38psi might be a touch low, but plenty to get you back in off the trail.

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I found this chart which lists tyre pressure for various sizes of tyres and cartridges. It doesn't list 29 inch tyres, but with a little bit of maths and physics (and a little bit of hand-waving) I calculate that the pressure in a 29 inch tyre is going to be about 10% lower than a 26 inch tyre.

The chart says 40 psi for a 26 inch tyre, so you'd be looking at about 36 psi for a 29 inch tyre. Which is a bit on the low side.

[Edited to include the link posted by @Grumpus27]

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Unfortunately, that chart isn't particularly useful. 27"/700C tires range from under an inch width to about 2", and the volume is a function of the square of the width, so that's a 4x difference. – Daniel R Hicks May 27 '12 at 20:20

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