Picture of Automatic bicycle pump
Fill your bicycle wheels with conveniently available pressurized air stored in automobiles.
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Step 1: Materials

Picture of Materials
You need a 50cm-100cm long air hose and two chucks. Make sure the hose fits very tightly on the chucks.

Step 2: Assembly

Picture of Assembly
Push the hose onto the chucks. It should be a very tight fit. If it is too tight you can soften the hose by heating it in warm water.

Step 3: Steal some air!

Take your bike and go find a hummer (or some other overweight vehicle). Fold the hose in your hand so you don't waste any precious energy. Attach one end to the automobile tyre and the other to your bike. When you unfold the hose you can hear a hiss. That is the sound of air flowing to your bike wheel and the world becoming a better place :) Fold the hose again before you detach it from both vehicles.

Remember! Thou shalt not steal air from public transportation. Public transportation is good.
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muddog151 year ago

Out of air.. OH! There is a scrapped car there with still inflated tires... "Hiss" There we go. :)

This works well, because it gives you just enough air to cruise on home.

feeblington2 years ago
we should only steal from gas-guzzlers
onestaff2 years ago
It would really put an elderly person in a predicament if you "used" their tire's air for your bike tire and stranded them, needing assistance to change their tire! If you ever come back to your vehicle and discover you have two very deflated tires, ( hopefully on the same side! ), you'll know that your instructable was remembered by someone who needed air in both bike tires. What goes around...comes around.
thedahlpod9 years ago
hell yeah! I'm lovin' this. So simple. I can't believe I didn't think of this or seen this before.
Yes, except for the fact that this doesn't work!

As many have said in this comment section, this will only further deflate your tires, or inflate them to a low point. Believe it or not, bicycle tires require a higher pressure than do car and even truck tires.
Someone made a remark about it being "common sense" that an automobile have a higher tire pressure, but this is solely based on assumption. And we all know what happens when you assume...

It's a great concept, but there's no way to practically apply this. The pressure source being suggested in this Instructable is simply inadequate.
I agree, my bike tires (27") require 100 lb of pressure.
Yeah. But my unicycle runs at less than 30psi :)

Note; I would never do this - it's stupid and dangerous although a very clever idea
What you can do is pile weight on the car first thus increasing the pressure. Just looking at my jeep it has, say, at least 80 in^2 of tire in contact with the ground. Of course, the tires will flatten out even more as you add weight and/or suck out air, but let's say to get from 40 psi to 110psi you only need to pile 5,600 pounds on top of the vehicle for an adequate pressure increase. So with a good supply of bricks and rocks you should be in business.
Brilliant! So instead of carrying around a small hand pump on my bicycle, I'll carry around this air-stealing device, and a mere 5600lbs of bricks! It's fool-proof!
Maybe that's why some &%$# piled a bunch of rocks on my Suburban! I was wondering, until I read this 'ible.
what about the volume of a car tire vs. a bike tire and the weight of the car increasing the pressure?
The only way that the weight of the car could increase the pressure is if the tires were inflated before they are installed onto the car. Since car tires are inflated after they are installed on the car, the 35psi that is standard for car tires has *already* taken into account the extra weight of the car compared to the bicycle. 35psi is all it has, tops, and you cannot use a 35psi car tire to inflate a bike tire to anything approaching it's recommended pressure.

This kind of idea is only useful in an emergency stopgap kind of situation. Like, you're out riding, you get a flat, you don't have a real pump on you, so patch your tire and then you use this trick to get your tire up to 35psi, and then you immediately ride straight home to where you have a real pump to get your tire up to the proper 60-120psi that it likely requires (depending on what type of tire it is).

This is not the kind of thing where you say "oh, my tire's a little low, I'm gonna go fill it up from a car tire." doesn't work.
that kind of depends on the bike too. On the whole I agree with what you're saying but you've over generalized bikes. OK some racing bikes use over 100psi but the majority of mountain bikes are happy in the 40psi range. I knew a guy who had a massive downhill bike with 3" wide tyres and he ran his at about 12psi.
Stealing air isn't good though. I'd be pretty annoyed if someone did it to me. Not everyone checks their tyres as often as they should.
most cars are 25 to 35 psi, so the low range of bike tires being 40 psi doesn't really help the case. Also on the big suvs (which he is probably targeting to be green) the tires being low greatly increases wear and adds to the chance of a blowout or a rollover. At any rate it can lower the life of the tire, which is not eco-friendly to replace. I can't imagine why someone would do this instead of getting a little portable pump, bike tires are low volume and topping them off doesn't take long.
OK for the sake of a few psi I'm finding this all a little pedantic now. Yes I said 40psi, and yes I'm aware that car's tend to be lower than that. The point I was trying to make was that so many people in these comments are talking about bike tyres being over 100psi and they're generally not. 40psi is plenty. OK so you can only steal 30psi from a car (which I still don't approve of) and you're not gonna want to ram a curb and get a pinch flat, but it'll get you home won't it?
The small change in PSI probably won't matter, but for the cost of these parts you could just get a small hand pump that clips to your frame and inflate your tires without being annoying.
your right i thought of that to because a common car tire is about 35psi my bike tire takes up to 60 psi thats double so this wouldn't work. i agree with you 100%
However, if you're a dirt jump or street rider, the average pressure (35psi) for car tires is more than adequate for your tires. Making this, a worthwhile mod. But in a way, you are correct, in that most road tires do require upwards of 90 psi. Don't like it? Buy a mousse or a tubular tire.
I agree with you about the pressure differnce inside the tyre, however have you thought about the weight of the vehicle and how much additional pressure that would apply? Would be interesting to see if this does work considering the weight difference. Perhaps it can work ?
pressure is the amount of force acting on a surface area. when a pressure reading is taken on a loaded tire, it has already taken into account all the weight the is being carried by the tire. fluid pressure (air) will always flow from high to low so they would equalize.
It still would work, but would only be practical for emergency situations.

For example if you changed a flat but didn't have a way to fill it up. If your bike tire is rated up to 80 psi, but car tires only carry up to 30 psi on average, that 30 psi will be more than enough to get you home or to another source of air.

However if your tire was just low, say 50psi and you wanted to pump it to 80psi. By plugging it into a car tire at 30psi, would deflate your bike tire until it reached an equilibrium just over 30psi, depending on the volume of both tires.
buses used for public transportation do have tires with PSI around 80-90. They would be great for filling up bike's tire
rv553 years ago
Where do you buy those chucks and hose?
Aleksi (author)  rv553 years ago
Depends very much on your location. I buy them from here
akrambler4 years ago
Wont be able to use a car tire. Period. but what you CAN do, is steal some air out of your other tire. both tires will be equal and while it will deflate your other tire a bit, you should have enough in both to get you to where you can pump them up. I made one of these a long time ago actually for my car. I took a little air out of each tire using this. I still have it somewhere, but now have a electric pump in my car.
This is by FAR the best comment on this thread... Your idea is so simple it actually works and BONUS I won't shoot you in the butt with rock salt for messing with the tires on my truck ;-) Thanks again for adding something useful to this convo..
west49rules4 years ago
Haha this wont work, car tires are inflated to about 35 psi bike tires should be around 50-60psi
You'd have to go for the air in another bicyle hehe
Or you could buy a bike pump for under $5 and not have to worry about the car owner catching you.
t0p4 years ago
So how exactly does one *steal* air anyway? Breathe in. Feel that stuff rushing into your lungs? Assuming you're not floating face down on the river, that's air. And it's *free*.

Before anyone starts up with the "oh but it costs money to fill your tyres at a filling station"... you're not paying for the air; you're paying for the privilege of using the station's equipment. Carry a foot pump in your trunk and air is free as a (free) bird.

Not that I'm defending this instructable. It's stupid. I've got this little pump that I always have with me when I'm on my bike. Flat tyres suck.

One other thing: why are some posters saying stuff like "typical anarchist". Someone who thinks only of him/herself is *not* a typical anarchist. Anarcho-syndicalism is *founded* on the notion of doing as you would be done by, sharing, and all that groovy gravy. Fools making foolish comments about "typical anarchists" are merely demonstrating their foolishness/ignorance/spite to us all. Duh!
Ole bally4 years ago
is there some reason why you wouldn't use a goop type product like 'tyre weld' and run it in yr wheels permanently thus avoiding the flats totally?
jack0024 years ago
1. I need 110psi, thats not enough
2. STEALING air pressure from strangers? This is what instructables has come to? I pass.
3. The process is so simple, I can do it without needed a website.

Fail. Possibly epic.
Cupajo4 years ago
This may be the douchiest thing I've ever seen on Instructables. Don't do this. Don't mess with other people's stuff. Seriously.
severepb4 years ago
if you get a flat, then just airing your tire up a bit will get you to a gas station or home.

think people... also, they have made this before on
aaron ross made it.

but i ride bmx and i air my tires to 110psi
Or, I know this is crazy, but you could walk your bike to the gas station.
You really shouldn't fill bike tires with the high-pressure hoses at gas stations, unless you want to risk eventually blowing the tire off your rim. Also, about half the bikes on the road today have Presta valves, not Schrader, which car tires have.

Also, walking to a gas station may be a 3mi walk, or more.
Then buy a pump. Don't mess with other people's stuff. If you can't walk 3 miles, you are not healthy enough to ride a bike.
1: I carry a pump and a CO2 on every ride, plus a spare tube.
2: As everyone else has already said, this doesn't work anyway.
3: I wasn't suggesting people steel air, I was warning against gas station hoses.
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