Will 16g gas inflate a 29er tyre

?

The smart arse and perhaps unhelpful answer is that it depends what pressure you want…. I find yes for get you home style pressures; no for keeping on riding at full tilt. I’m not racing though so happy to top up with a hand pump.

You can get a 24g cartridge no?

Based on a 700x35c CX I’d say not really!

Nope

Nah, you’ll need two Carl.

And obviously that means carrying four…

No, my brief foray into co2 inflators found I needed two anyway.
I still have a box or two of canisters, if you can forgive the flagrant opportunism…
£5 + post. 😀

Yes, to a bit under 2 bar.

You can calculate the pressure as follows, I think: (warning, sums coming up)

Volume of a 29 x 2″ tyre = 4.5 litres
(imagine unrolling the tyre into a cylinder, it would be 28x(pi) inches long, one inch radius.)
Volume of cylinder = length x (radius^2 x pi)
= 276 cu in
Convert to metric:
276 *(2.54^3) = 4528 cubic cm.

Molecular weight of CO2 = 44 (12+ 2 x 16) so 1 mole of CO2 has a mass of 44 g.
Therefore 16 g of CO2 = 16/44 = 0.36 moles of CO2
One mole of a gas occupies 22.4 litres at room temp, so 16 g gives:
22.4 x 0.36 = 8 litres

Put 8 litres of gas into a volume of 4.5 litres and the pressure goes up like this:
P (in bar) = 8/4.5 = 1.78 = 26 psi

I’ve tried it in a race and it felt about right.

A 25 g can will give you 26 x (25/16) = 40 psi
In a 2.25″ tyre you’ll get a bit less pressure, say 20 psi from 16 g, 32 psi from 25 g.

Good timing on asking this as I’ve been wondering too. So been taking one with me along with my trusty hand pump.

Put it into practice yesterday after a pinch.

Nowhere near as in depth as above but I reckon 1 16g canister put about 18/20psi into a 2.1 Crossmark on a Bonty rim (internal width 21.9mm). I then topped it up with 50 strokes of the hand pump to a squeeze pressure I was happy with (much less tiring that the usual 200 or so from flat!)

There was still a tiny bit of pressure left in canister but wasn’t enough to still be forcing it into the tube.

Ta.

Yes.

Only to about 15/20 psi if you’re lucky

A 2.3 29″ tyre will be very soft so will need topping up with a pump or use another cartridge. A16g cartridge will inflate a 26″ tyre to approx 40psi and a 700c road tyre to approx 120psi according to the packet my cartridges came in. Obviously greatly varies with the size of tyre you have. Even using one cartridge and topping up with a pump greatly reduces the amount of hand pumping though.