Newbie question - pumping tires

Discussion in 'Cycling Equipment' started by tepidarium, Feb 18, 2004.

  1. tepidarium

    tepidarium New Member

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    Hi,

    I know this may seem to some as a stupid question but need an answer - my tires need to be pumped to 120 psi. I have a gauge on my pump that makes this easy. The directions with the pump say to pump until the gauge reads the right psi. Then, obviosuly you are finished.

    Basically, what happens is taht I pump up to 120 psi, but then, when I release the pump head from the valve (I have the screw in Presta? valvue) air is released...Resulting from this unavoidable air release is a loss in pressure. My question is: should I overpump to compensate for this air release when removing the pump-head from the valve...or is this normal and I shouldn't worry about it.

    thanks for your answers..sorry if this is a dumb newbie question...
     
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  2. Hitchy

    Hitchy New Member

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    G'day,

    It's not a stupid question, so don't stress...If ya don't ask you'll never know the answer...anyway....the normal loss when removing the 'pump head' should be minimal. It sounds as though you are having some trouble getting the pump off the valve in a reasonably efficent manner. Practice makes perfect!. Don't 'tear' at it or pull too hard before releasing the pump, or you'll end up ripping the 'screw' of the valve off. Good luck,

    cheers,


    Hitchy
     
  3. eric_the_red

    eric_the_red New Member

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    Most of the air you hear being released is from the hose on the pump. Air pressure will keep the tire valve closed so if you pull the pump head straight off no air should come out of the tire, and the pressure will be the same as the guage.

    Also note the 120 psi on the tires is the maximum recommended pressure, you don't have to go that high. You might find the ride more comfortable with a bit less air.
     
  4. lokstah

    lokstah New Member

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    Agreed. That nasty HISSSS you hear when you release is as much a result of pressure in the pump shaft, hose, and valve head as it is the sound of precious air escaping your tube. In reality, what you lose is minimal.

    As Eric pointed out, 120 psi is a great goal but it's hardly a concrete figure; as a max figure, the recommendation is that you not exceed 120 psi -- not that you aim for it. For road riding, anything approaching 100 psi tends to be sufficiently safe and efficient, no matter the model tire. See what feels best for you in that range. Good luck!
     
  5. skillerv

    skillerv New Member

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    The ratings on the tires are just recomendations ive been riding michelins' for the past 5 years and most of them have a max of 110psi but ive always ridin mine at 125-135 and ive never had any problems so if you want just put more in and dont worry about it. but the air coming out you hear is most likely the air left in the hose.
     
  6. tepidarium

    tepidarium New Member

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    Thank you all very much for your replies!
    I have a nashbar pump that has a lever lock on the hose. The air hisses when I unhook the pump.

    once again, thanks.
     
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