9

I had a flat tire and replaced the tube. I just didn't realize that the tube was a thorn-proof tube when I bought it. It was the only spare one I had, so I used it anyway. Just now I replaced it with a regular tube. I figure I can keep this thorn proof one around just in case I get another flat.

The problem is, I can't get all the air out of the thorn proof tube to store it in the closet. It's schrader valve. I push the pin in and air comes out, but there is still a lot in there. I'm trying to fold it up like a tube of toothpaste while pushing the pin, and it's not working so well. I could cut it and patch it, but then I may as well throw it out and buy a new tube. Is there maybe some way to get my bike pump to work in reverse or otherwise completely deflate this thing?

  • 1
    I've seen anti-flat motorcycle tubes with double air chamber, so that when the outer chamber got flat, the inner one would keep some air to keep it rolling. Would this tube be that type? – heltonbiker Jun 16 '12 at 15:21
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    A Thorn-Proof tube might have one or two features not obvious. First, it may have sealant inside the tube already, which will make it feel like toothpaste. Second, it could have a much thicker outside wall, and be harder to manipulate. – Criggie Aug 18 at 0:50
11

According to Yehuda Moon (google it), you can take a properly-sized ball bearing (or even a pebble) and put it inside the valve cap, then screw the cap halfway so that the ball/pebble will keep the valve open.

Then, you roll the tube like toothpaste, and when you finish you remove the cap and the pebble to avoid the natural elasticity of the tube to suck back some air.

Hope this helps

  • omg genius way to hold the pin down! I used a pebble from the sidewalk that was just the right size. – Apreche Jun 21 '12 at 2:13
6

Yes, if you have a Schraeder valve then the core can be easily removed with a simple tool (available for a couple of dollars at any car parts place and some bike shops).

If it's a Presta, OTOH, the core is not usually removable, but it's quite easy to keep the pin depressed.

To get the air out of the tube, first fold it in half with the valve near (but not at) one folded end. Then roll up the tube from the other end, possibly making use of a piece of pipe or such to roll it around. Or use a can of soup or such as a "steamroller" to press out the air.

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    Actually, presta valves with removable cores are becoming more and more common. google.com/… – jimchristie Jun 16 '12 at 14:13
  • Usually it works nice to roll it around the non-valve folded end in case there isn't any rolling device around, too. – heltonbiker Jun 16 '12 at 16:14
4

Wedge the pointy end of the cap a Bic pen (the part that is intended to clip to your shirt pocket) into the valve when you try to roll it up. That'll wedge it open. Just pull the pen cap out when you've got it rolled up nice and neat and you'll be set.

EDIT: I originally mistyped my answer to say that you should wedge the pointy end of a pen into the valve. It's the pointy end of the cap that you want to wedge into it. Sorry about that.

2

With a schrader valve, you can buy a "valve stem remover" at most auto parts houses or big box stores auto department. They're inexpensive. It just slips right over the valve stem with the two "forked" prongs slipping in the recessed area of the stem to unscrew the valve stem. These are also handy to make sure the valve stem is snugged up on a schrader valve afte you've inflated the tire. If you remove the valve stem, this would make it easy to roll or fold the tube to remove all possible air. These valve stem removers used to be threaded on their large end, not sure if they are now days, but you could thread the tool onto the proper sized bolt ( thread size and desired length of bolt ), to make it easier to use.

2

I made a tool to do this.

Own work

I get a lot of punctures so end up patching about twice a month. I carry 2 spare tube and last-resort stickers, so I patch in the comfort of home not on the side of the road. This tool replaces the valve cap, and as it threads on a small bolt down through the middle is enough to press the schrader's pin.

It started off as a decorative cap that looked like this: Own work too

I lopped the end off, drilled a hole vertically on center and then "tapped" it for the small bolt for depressing the pin.

There are two holes through the sides to let air escape. One would have been enough, but two was quieter and less likely to be obscured. Two more might be good.

Originally the bolt was threadded to permit adjusting of the flow rate, but in practice you want the tube empty.

So I fit this then start folding the tube from the opposite side to where the valve is. I layer it into flakes about as wide as my hand and then pinch it around the bend with my fingers. Once at the end I swap the deflator for a normal cap. and then shake the tube out and reroll it with the valve in the middle.

If that's not clear let me know and I'll expand with more photos.


By "thread" I mean ramming a series of sacrificial bolts through a hole until it formed a thread-like shape. The chowdering on the outside is because my main tools were a drill press (pillar drill) and a machine vise.... ideally I'd have used a lathe, and some better way of supporting the cap. An old valve stem could have been a lot better. And I should have put some light chain under the bolt, to provide a handle. This little thing likes to drop and roll under stuff.

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    I've done the same, but starting with a plastic valve cap that came with a tube. For presta you might only need the vent holes, depending on the cap – Chris H Aug 18 at 6:58
  • @ChrisH Presta's quite different. If you get it right the presta valve core will sit in the open position, because it has no spring like a schrader valve core does. Presta is only held closed by the pressure of the air, which is why its good for higher pressure tyres and poor for low pressure (MTB/fat tyres) – Criggie Aug 18 at 8:42
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    yes, but when rolling the tube to get the last bit of air the valve tends to shut. I don't know whether it's the less-than-steady airflow, the flapping around, or some combination, but something to hold the screw in helps when I roll tubes in mid air – Chris H Aug 18 at 9:56
1

Vacuum cleaner with an adapter down to Schrader size? Pumps usually have valves to avoid pulling in air. You do not need a hard vacuum, just a minor one.

A little gross, but if you do not mind, you could use the vacuum device god gave you. Use a valve tool, remove the valve stem, and then just suck the air out? Probably taste icky, but I would not imagine it would be dangerous. (Taste of the air, vs anything else).

A valve stem tool can be faked with a pair of narrow tweezers. The valve stem itself has the pin in the center of a rectangular piece. You just grasp two sides and twist to unscrew. Here is one on Amazon for $0.39! (Haha! And $7 in shipping! Talk about adding insult to injury...)

  • Would not recommend sucking on a tyre valve - there is often white talc-like powder to stop the butyl rubber sticking to itself, and there may be sealant in there too, Not good to ingest either. – Criggie Oct 28 '16 at 21:30
1

Guess none of you guys are old enough to remember the old tube caps. The had a forked end that you used to unscrew the valve stem.

https://images.amain.com/images/large/bikes/rema/37.jpg?width=950

You could remove or loosen the core in the schrader valve with this tool, allowing the air to escape as it is rolled up.

You could use a tubeless valve to make a tool by screwing it into the tube cap into using pliers. This eliminates having to use pliers on the tube cap if it is on too tight.

  • I've added a photo to show what you mean. However I don't get your point in the last paragraph - want to use edit to expand on that ? How would you use a tubeless valve to make a tool for this purpose ? – Criggie Aug 18 at 0:48

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