27.2 seatpost and inner Co2 cartrige

I need help:
I’m hiding a Co2 cartridge inside my 27.2 seatpost (I already carved the saddle to reach that spot). But I’ve found an issue my seatpost has an inside funnel at saddle fixing plate side end.

I need to find a 27.2 seatpost large enough to insert a Co2 cartridge in it!
Can anyone take a look at his/her spare parts and let me know?

just tried an Impact 27.2 seatpost and a normal Co2 cartride (from https://www.genuineinnovations.com/ ).
Fitted pretty nice, but almost got stuck (when the top comes into the smallest part with too much speed/force).

Thank you!!!
Did you test a 20g cartridge or a smaller one?

How many cartridges needed?

I did some early research regarding a Co2 pump, but I was discouraged to find out that big wheels fat tires need quite a bit of volume. So, these CO2 pumps are better suited for skinny tour d france tires.

Does anyone know if a single cartridge would be able to pump up a 26 or 27.5 inch wheel that is 3 or 3.5" wide to about 35psi?

My hope would be to ride on a road(30-35psi) about 3-5 miles to get to an off-road spot. Then release air down to 15 psi for offroad traction/fun. Then pump the tire back to high pressure for the return trip. It would be nice to not have to strap a manual pump onto my back.

They aren’t capable of that. ~14psi on a 27.5"x2.8ish is what I gather you get from a 20g.

Wasteful and expensive, for almost 0 weight savings compared to a good minipump… I see a point for c02 cartridges as emergency backups for: tubeless tires that need to be popped on fast, and road bicycles, that need to get high pressure, which small pumps are bad at. But for “scheduled” use, no. My minipump cost me 12$, and has probably pumped up tires 50+ times, and created 0 waste in the process.

Strapa pump to the back of the frame/seattube with velco if you don’t want it on your back.

I need it to change tire pressure, not to completely inflate it

I use a sealant and do not suffer from a flat (I hope that the way the sealant is intended for).
I use the tire well inflate for road riding to the trail. Once I deflate it a bit to ride on sand… it cost me alot to travel back home at the end of the day…I wish I could have a bit more PSI. So that why I’m riding a G27,5 (heavy) in a light wheight setup.
Hopefully I won’t need to lower and to raise the pressure again, but I’ll prefer to be ready for it

Maybe I should leave this, but anyway…

Call me old fashioned, but it seems absolutely insane to me that using a disposable cartridge to inflate a tire is an acceptable thing. It’s stupid, easily avoidable waste, for what?

-Saving 2 minutes?
-less than 100g of weight saving?
-Saving effort from your muscles while you are out doing exercise?

As I said, for setups that require them (tubeless to pop them back on, or high pressure road bikes). But none of the reasons I mentioned above are valid in my point of view.

The only thing he may waste is his money. All of us do it. Everything else is recyclable.

you are right I’m in need to avoid unplanned muscle exercises: I am diabetic. The time I ride in the sand I did expend too much energy during my ride back at the campimg and I ran out of blood sugar almost completely before arriving at the tent… I was lucky because I did manage to ride the last kms, but I had a really bad caring experience.
Now I ride always with my phone, I use always sealant and I prefer to avoid any unplanned fatiguing activity. And I ride as usual full with sugar added water/juice

Also I like the idea to experiment

But I understand your point of view. Maybe others could try to use a mini pump in the seatpost, but a minipump will require 300 strokes for a 3" tire… Too much for me at the end of a day ride

Totally agree. In a time of climate change and waste control and over consumption, it’s walking on our head to think it’s ok to do that. An air pump is a few grams in the bag and it won’t create more unnecessary waste.

On my road bike, I often see empty cartridges by the road side, which makes me furious. If you use the cartridges, you still need to carry the adaptor, so you might as well carry a mini-pump. And what do you do if you get 2 flat tires? It’s happened to me. The 2 situations where cartridges might be justified are: 1) long distance unsupported race, where you must minimise time to repair and be sure of full inflation, and 2) physical disability of some sort. But don’t dump the empty cartridges!

I’ve have them for years - but never ever used a single one.
I put them in my luggage, when I go to performances, together with a new innertube and tools to replace one. Just to travel minimalistic.
When I bought it it was much cheaper than a decent Zeval micropump which truly can do high-pressure, so then decided to have this.
And the waste… is recyclable. Just like cans for worms, soda, beer, veggies, etc.
I don’t feel guilty towards the planet or my wallet yet. But feel annoyance when I see the waste where it doesn’t belong.

… for those who can’t scroll up :wink:

I’ll add that to the list of valid reasons to use CO2 cartridges. Everyone who doesn’t literally die from exhaustion won’t be excused by me, even though my opinions shouldn’t always be taken too seriously anyway.

You are right and your opinion is seriuos. I’ve also considerer something like Airshot or Rideair or Schwalbe Air Booster… but they are too big and I just need a bit of pressure, not a new inflated tire.

However… I was looking for tests or other ideas to hide tools inside my seatpost… if anyone will help me that way I’ll be more pleased than to receive help to find the slimmest mini pump able to inflate a 3" tire with just few strokes (it simply doesn’t exist)

For your specific (and as I said, I think legitimate with the knowledge of your diabetes) requirements, I guess CO2 is the only real option. I personally would maybe look at a combined pump/co2 head https://eu.crankbrothers.com/collections/hand-pumps/products/klic-hv-co2 or similar. The last time someone who I was riding with used co2, I saw all the downsides: you can only inflate once, and he ran low on pressure again later (burped air with a tubeless setup).

Seatpost is hard since it’s really slim. I haven’t seen any good ones yet. (Some people put tire levers there, but I don’t really think that’s worth it. My idea has recently been a really small bag under the saddle, attaching to the bolts of the back bumper, and the back of the seatpost. I don’t think one would notice it there while riding. For either patches and a set of allen keys, or a small first aid kit. There are some similar to what I’m thinking of made for bikes, and I think some of them could be adapted pretty easily.

Since I now have a dedicated backpack for riding that has a toolkit and first aid kitpermanently in it, I haven’t really been looking for a suitable model much anymore, but that’s where my head goes.

What about this pump?

It could be a good idea! I just cannot find any review. Also there’s no news page on their website or any kind of link to a specilistic site’s review… so I won’t ever spend any money on that pump

There are several different brands of these handheld Mini Air Inflators available and a few hundred ratings from owners can be found on Amazon. Do a Google search for “Mini Air Inflator” to find them. In general they seem to be highly rated.

The Chicholic Portable Air Compressor Mini Air Inflator Electric Hand Held Tire Pump seems to be the most popular. I’ve never used one.

That’s an interesting concept. But having looked at their video, I doubt it will fit into a seat post. It looks big in the hand of the user - and they clearly chose small hands for the demo.