Losing air, but no puncture?

Hey guys,

Yesterday I had to rotate my tire, so after, I made sure and pumped it
to 22 psi.

Today, I went for a ride, was doing awesome trials. Checked my psi, and
I saw it was 19 psi.

I pumped up my tube and put it into the bathtube and there are NO
PUNCTURES.

How can this be?


--
hungry4uni

*ŤŔϊãĻş
ЦИΪĈҰĆĻέ*
------------------------------------------------------------------------
hungry4uni's Profile: http://www.unicyclist.com/profile/16147
View this thread: http://www.unicyclist.com/thread/74441


Posted Via Usenet.com Premium Usenet Newsgroup Services
----------------------------------------------------------
http://www.usenet.com

Give it a day and see if it's still leaking. Have you made a large
change in elevation? Could your valve be leaking? Is your pressure gauge
really that accurate?

In any case, if the air isn't staying in the tire it *is* leaking.


--
johnfoss

John Foss
Email: "jfoss" at "unicycling.com" -- www.unicycling.com
-----------------------------------------------

"False facts are frequently formed from figures fabricated from fear
fired fiction." -- Harper
------------------------------------------------------------------------
johnfoss's Profile: http://www.unicyclist.com/profile/832
View this thread: http://www.unicyclist.com/thread/74441


Posted Via Usenet.com Premium Usenet Newsgroup Services
----------------------------------------------------------
http://www.usenet.com

You lose some air by measuring the pressure, especially if you slip a
little bit. As John says, a large change in altitude can change measured
gauge air pressure. It would take about a 45 degree Fahrenheit change in
temperature to change the tire pressure 3 psi when in the 20 psig range.
A combination of these could be cumulative.


--
harper

-Greg Harper

*jc is the only main man. there can be no other.*

"Natural logs are what you ride on a Mun'e'." - kevinalexandersmith
------------------------------------------------------------------------
harper's Profile: http://www.unicyclist.com/profile/426
View this thread: http://www.unicyclist.com/thread/74441


Posted Via Usenet.com Premium Usenet Newsgroup Services
----------------------------------------------------------
http://www.usenet.com

When you put your tire gauge in, it is letting out some air, this is
probably what is happening.


--
ntappin

'how to build a strong comfy saddle from junk.'
(http://tinyurl.com/hxcb3)
------------------------------------------------------------------------
ntappin's Profile: http://www.unicyclist.com/profile/10800
View this thread: http://www.unicyclist.com/thread/74441


Posted Via Usenet.com Premium Usenet Newsgroup Services
----------------------------------------------------------
http://www.usenet.com

So I went back and assembled my unicycle again, and pumped it to 22
psi.

If I understand you guys correctly, if I keep putting the tire gauge
in, the pressure will decrease. If the weather changes, (where I live is
in my opinion the town with "weather moodswings") that could raise or
lower the pressure.


What I'll do is not measure it any more. It's at 22 right now and I
know it.


--
hungry4uni

*ŤŔϊãĻş
ЦИΪĈҰĆĻέ*
------------------------------------------------------------------------
hungry4uni's Profile: http://www.unicyclist.com/profile/16147
View this thread: http://www.unicyclist.com/thread/74441


Posted Via Usenet.com Premium Usenet Newsgroup Services
----------------------------------------------------------
http://www.usenet.com

I've never personally experienced this, but back a month or so ago on a
ride with Terry, he told me that temperature plays a pretty big role. He
said that car tires inflated to 40 PSI on a cold morning might have 55
PSI in them on a hot afternoon. Now, if air were an ideal gas, this
would be impossible, but it's clearly not, and I don't know enough more
about it to know for sure anything So....... could it be the
temperature at which you pumped it up?

Was it really hot when you pumped it up, and cold when you just tested
it?




I AM sure, though, that tires do lose air quite naturally. I usually
pump my 36er back up to 60 from 40 or 45 once every week or two. That's
a cool 25 percent change. Even that, though, isn't nearly as fast a leak
as what you've described. Couldn't tell ya from here. :-)


--
chuckaeronut

Uni to work to eat to live to uni to work to...!
------------------------------------------------------------------------
chuckaeronut's Profile: http://www.unicyclist.com/profile/14677
View this thread: http://www.unicyclist.com/thread/74441


Posted Via Usenet.com Premium Usenet Newsgroup Services
----------------------------------------------------------
http://www.usenet.com

With low pressures like you are talking about it is most likely losing
air when you are checking the pressure, but it could be a membrane leak.
I have seen old tubes lose considerable air through the rubber, and it
can happen if you are running a tube that is thin walled, or too small
for your tire.


--
jtrops
------------------------------------------------------------------------
jtrops's Profile: http://www.unicyclist.com/profile/17262
View this thread: http://www.unicyclist.com/thread/74441


Posted Via Usenet.com Premium Usenet Newsgroup Services
----------------------------------------------------------
http://www.usenet.com

Check the size of your tube and if the valve is OK!

I bought a 2.0 tube at Denmark and used it in there and it was always
18lbs. When I came back I made a hole while assembling the wheel and
changed the tube for a national 1.75 tube... I ALWAYS have to pump it...
Everyday...

Bad quality tubes are around and good ones are expensive... I'm riding
flat I don't care, but if you ride street always check... and with big
drops you'll probably loose more air!


--
pedrotejada

'*Kris Holm Unicycles*' (http://www.krisholm.com)

*Brazilian Unicycling Team*
------------------------------------------------------------------------
pedrotejada's Profile: http://www.unicyclist.com/profile/14471
View this thread: http://www.unicyclist.com/thread/74441


Posted Via Usenet.com Premium Usenet Newsgroup Services
----------------------------------------------------------
http://www.usenet.com

It's a 20x1.75-2.25 tube, so thats not what it is.

I think it's my incessant checking thats the problem


--
hungry4uni

*ŤŔϊãĻş
ЦИΪĈҰĆĻέ*
------------------------------------------------------------------------
hungry4uni's Profile: http://www.unicyclist.com/profile/16147
View this thread: http://www.unicyclist.com/thread/74441


Posted Via Usenet.com Premium Usenet Newsgroup Services
----------------------------------------------------------
http://www.usenet.com

hungry4uni;1136665 wrote:
I think it's my incessant checking thats the problem



Maybe, But I have this problema and lots of trials riders too... Joe is
ALWAYS pumping his tube... ALWAYS...

With big pre hops and drops your valve will loose some air... It's a
fact...


--
pedrotejada

'*Kris Holm Unicycles*' (http://www.krisholm.com)

*Brazilian Unicycling Team*
------------------------------------------------------------------------
pedrotejada's Profile: http://www.unicyclist.com/profile/14471
View this thread: http://www.unicyclist.com/thread/74441


Posted Via Usenet.com Premium Usenet Newsgroup Services
----------------------------------------------------------
http://www.usenet.com