Parasitic bike pump steals air from car tires

Energy & Sustainability
Parasitic bike pump steals air from car tires

Aside from the small issue of car tires not generally being under as much pressure as bike tires, this emergency bike pump by Instructables user Aleksi is pure genius. Just hook up to the tire of a nearby car, and you’re good to go! It’s probably not much use in the woods, though. [via inhabitat]

38 thoughts on “Parasitic bike pump steals air from car tires

  1. Nate says:

    Could this be considered theft? You can get busted for siphoning gas…

    I don’t know. What if you siphon air out of an already low tire, leaving the car owner with a flat?

    It just seems sheisty to me. I’m pretty sure I’d be pissed if I found someone siphoning my tires.

    Stick to the traditional bike pump. They’re lightweight, and work anywhere there’s atmosphere.

    That said…it’s an interesting hack. :)

  2. Alan says:

    This is absolutely a brilliant hack: a clever adaptation of existing tools to accomplish a well-known task in an entirely new way.

    But it’s an absolutely horrible idea. Tampering with car tires is tampering with someone’s life. There are dozens of ways this could go wrong, and many of them end with an innocent person getting killed or seriously injured.

    Reduce a car’s tire pressure below a critical threshold (which is higher than most people realize), and you significantly reduce the tread’s traction in marginal conditions, accelerate wear, make blowouts more likely, and increase braking distance. Even if you just end up giving someone a flat, changing a tire carries its own risks, all of which would be your fault.

    Admire this hack, but please do not use it. Ever.

  3. Simon says:

    I would be very, very grumpy if someone changed the pressure in my tyres. As Alan says this is dangerous. A few PSI difference in the pressures on my car make a noticeable difference to how it handles.

  4. theophrastus says:

    Probably i’m missing something obvious but your average car tire pressure is ~30psi and your average bicycle pressure is ~60psi. But i suppose the key here is “emergency”? and a 30psi bike tire is ride-able?…

    1. CircuitGizmo says:

      “Probably i’m missing something obvious but your average car tire pressure is ~30psi and your average bicycle pressure is ~60psi”

      That’s OK because car tires are much BIGGER. :-P

      (Last time I tried out my sense of humor here I hooked someone who was senseless. That was a joke. It was meant to be funny, although your mileage may vary on that… especially if your tire pressure is low ifyouknowwhatI’msayin’)

  5. Shadyman says:

    Aside from all the reasons given above, the biggest I could see is that lowering the tire pressure in a car would also decrease its fuel efficiency.

    That and I’d imagine it’d make for a good way to blow up a bike tire if you’re not careful.

    Though, I’m not going to put a damper on neat hacks.. +1 for thinking outside the box.

  6. Rhudson says:

    You could always _ask_ before taking a little air.

  7. says:

    I’m having a difficult time imagining a situation where I have such an urgent need to ride my bicycle that I’m willing to put up with a half-pressure tire, even though my car is RIGHT THERE.

    P.S. those those ends have valves on them? And aren’t the valves now facing in opposite directions?

  8. JohnnyPrimus says:

    These devices used to be pretty popular with the bmx crowd, especially the street riders who deal with pinch flats fairly often. Bringing a spare tube (or patch kit for minor issues) was easy, finding air not so much.

    These would normally be used to take air from busses which run higher pressure (and have more air [and often times more tires]) than cars. Certainly a shady means to an end, but you can’t deny the functionality.

  9. MR says:

    Sort of useless. Let’s see, you need air – that must mean

    1) the bike has been sitting for a long time, or
    2) someone deliberately let the air out of your tire(s), or
    3) you just patched a puncture and don’t have a pump, or
    4) you just put a new tube in the tire and know for sure there is no puncture.

    If you use this device to fill those tires you will cause a puncture the first time you ride and hit a bump or rock because the tires will be underinflated- a condition guaranteed by this device, the very condition that probably caused your tire to go flat in the first place. You will quickly be in the same or worse situation than when you started.

    Better to invest $10 in a small pump.

  10. whitcwa3579545 says:

    This is like making an extension cord with two male plugs so you can electrify your house from your neighbor’s outlet when he is on 120 V and you are on 240V. It is illegal, unsafe and likely to result in a beating.

  11. craig says:

    This is a prime example of today’s youth. When I was a small kid I knew not to hop onto the riding mowers at Sears because I would have been EAR TWEAKED right off it because “that is not yours” or “that is not a toy”. I respected stuff that did not belong to me. Today’s youth will not only touch what doesn’t belong to them, but take from it with no second thought about it. What if the air in the car is not air, but $60 worth of nitrogen on a sports car? Is the valve cap going back on? Likely not, geting dust and salt in the valve so the next air-up has a poor seal on the valve.
    YOUNGSTERS: If it don’t belong to you, don’t touch it. Respect other people’s property.

    1. SteveYYC says:

      That’s more than an oil change around my neck of the woods. I thought the potato-chip and printer-ink industries had figured out how to sell almost nothing for ridiculous profits.

      I agree with this message’s sentiment.

      We cyclists get enormously ticked off when someone messes with our bike. Drivers have the same reaction. Respect the property of others, even if it’s something as (seemingly) minor as tire pressure.

  12. Sam says:

    I am disappointed to see this reposted on Make, especially with such enthusiastic acclaim. Practically it is a completely flawed idea and it is also ethically questionable.

    Must try harder.

  13. Peter says:

    A small high pressure pump would occupy a smaller volume and weigh the same.

  14. DriveDog says:

    Ask permission, absolutely, if at all possible. But 30 psi from car tires isn’t going to do much for road bikes. I suppose one could ride an ATB on that, with significantly high rolling resistance. Buses, trucks, even SUVs with truck tires offer much more pressure, but I still doubt you’re going to find 110 psi. If someone’s paying extra for nitrogen, they’re probably paying extra for oxygen-free speaker cables and $50 for HDMI cables, and you can easily convince them that their tires need venting or that you’re just tasting the nitrogen to make sure it’s pure. Nothing else tastes like pure nitrogen, you know. I keep my tires inflated with helium-3 not because it’s inert but just because it’s rare on Earth. Don’t steal it.

  15. Simon says:

    If anyone is interested I actually tried this out the other day with bits of junk around my garage. I wanted to know how it would work. Yep, a 30 PSI car tyre won’t fill a bike tyre to 30 PSI. I figured both would end up at a lower, but equal pressure. They don’t though. There is a difference of a few PSI.

    I didn’t do a full on scientific analysis so these results aren’t great but they are interesting:

    I think DriveDog is right about nitrogen in car tyres. A bit pointless really. They do use nitrogen in aircraft tyres though. Now those are at a much higher pressure (200 PSI and more) and from what I gather nitrogen is used because it is less liely to cause corrosion of the alloy rims aircraft use and because it won’t support combustion which apparenty can be an issue in aircraft tyres running at much higher loads and temperature than your average car tyre. There is a link to a Goodyear PDF in the page above about aircraft tyres explainigng some of this.

  16. Chris W says:

    We use nitrogen at work to fill studio TV camera pedestals because we get our nitrogen from refillable gas cylinders. They provide the high pressure we need at a low cost since we don’t need many CFM. One tank lasts over a year.

  17. Car Parts says:

    I don’t beileve that and also it is very good and a nice information regarding it. I am much impressed by your information. It is much great and also beneficial.

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