Change Air In Tires

[Rick Ankrum]

With all the talk of greenhouse gases I am concerned with having tired
air in my bike tubes. How long can I can go between evacuating the air
and putting new air in? I am afraid that the air molecules will all be
pushed to the outer edge of the tire if I do not evacuate the tubes on a
regular basis. This could cause the tire to put too much weight on the
road and thus I am not be able to get at top speed quickly.

Does tapping on the tread move the molecules back into the center of the
tube?

9-)

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[Leo Lichtman]

"Rick Ankrum" wrote: (clip) Does tapping on the tread move the molecules
back into the center of the tube?
^^^^^^^^^^^^^^^^^^^
If you ride on rough pavement occasionally, that is equivalent to tapping on
the tread--maybe even better--so you should have nothing to worry about.

 

[Leo Lichtman]

"Fritz M" wrote: I would think the centripetal force of the rotating tire
might overcome any "jostling" of the molecules that comes from riding on
rough pavement. (clip)
^^^^^^^^^^^^^^^
There could be some effect of centripetal force (or centrifugal force,
depending on how "sophisticated" you want to sound,) but please bear in mind
that the portion of the tire at the bottom, where the jostling is taking
place is STATIONARY. There must be some degree of roughness at which the
rotational forces equal the mixing forces. For higher roughness, the air
would remain mixed, and for lower roughness, segregation would progress.

 

[Bill Sornson]

Rick Ankrum wrote:
>
>
> With all the talk of greenhouse gases I am concerned with having tired
> air in my bike tubes. How long can I can go between evacuating the air
> and putting new air in? I am afraid that the air molecules will all be
> pushed to the outer edge of the tire if I do not evacuate the tubes
> on a regular basis. This could cause the tire to put too much weight on
> the
> road and thus I am not be able to get at top speed quickly.
>
> Does tapping on the tread move the molecules back into the center of
> the tube?

No, because of moisture (condensation). I rigged up a "talcum injection
system" to my floor pump to prevent this very problem. No more bits of air
stuck to the inside of MY tubes, TYVM.

(I'm working on a portable version for those roadside flats; also keeps
one's pits baby fresh.)

Bill "clean 'n dry" S.

 

[di]

"Rick Ankrum" <[email protected]> wrote in message
news:[email protected]...
>
>
> With all the talk of greenhouse gases I am concerned with having tired air
> in my bike tubes. How long can I can go between evacuating the air and
> putting new air in? I am afraid that the air molecules will all be pushed
> to the outer edge of the tire if I do not evacuate the tubes on a regular
> basis. This could cause the tire to put too much weight on the road and
> thus I am not be able to get at top speed quickly.
>
> Does tapping on the tread move the molecules back into the center of the
> tube?
>


This is the very reason why I use tubeless tires.

 

[di]

"Rick Ankrum" <[email protected]> wrote in message
news:[email protected]...
>
>
> With all the talk of greenhouse gases I am concerned with having tired air
> in my bike tubes. How long can I can go between evacuating the air and
> putting new air in? I am afraid that the air molecules will all be pushed
> to the outer edge of the tire if I do not evacuate the tubes on a regular
> basis. This could cause the tire to put too much weight on the road and
> thus I am not be able to get at top speed quickly.

One thing to remember when changing the air in your tires. When all the
molecules are pushed to the outer edge of the tire, it doesn't do any good
to let the air out of the valve stem because there is no air there. You
must poke a hole in the tire to get it all out.

 

[Bill Sornson]

di wrote:
> "Rick Ankrum" <[email protected]> wrote in message
> news:[email protected]...
>>
>>
>> With all the talk of greenhouse gases I am concerned with having
>> tired air in my bike tubes. How long can I can go between evacuating
>> the air and putting new air in? I am afraid that the air molecules
>> will all be pushed to the outer edge of the tire if I do not
>> evacuate the tubes on a regular basis. This could cause the tire to
>> put too much weight on the road and thus I am not be able to get at
>> top speed quickly. Does tapping on the tread move the molecules back into
>> the center of
>> the tube?

> This is the very reason why I use tubeless tires.

Poor deluded innocent. They use air, too, you know.

Bill "PS: it's 'tubless' in Usenet" S.

{sarcams mode off}

 

[di]

"Bill Sornson" <[email protected]> wrote in message
news:[email protected]...
> di wrote:
>> "Rick Ankrum" <[email protected]> wrote in message
>> news:[email protected]...
>>>
>>>
>>> With all the talk of greenhouse gases I am concerned with having
>>> tired air in my bike tubes. How long can I can go between evacuating
>>> the air and putting new air in? I am afraid that the air molecules
>>> will all be pushed to the outer edge of the tire if I do not
>>> evacuate the tubes on a regular basis. This could cause the tire to
>>> put too much weight on the road and thus I am not be able to get at
>>> top speed quickly. Does tapping on the tread move the molecules back
>>> into the center of
>>> the tube?
>
>> This is the very reason why I use tubeless tires.
>
> Poor deluded innocent. They use air, too, you know.
>
> Bill "PS: it's 'tubless' in Usenet" S.
>
> {sarcams mode off}
yea, but there some unknown factor that keeps the air molecules in motion
eliminating them from gathering on the outside of the tire or is it tyre on
the Usenet. My spell checker is not Usenet savvy, it says tubeless, must
return it to Microsoft for updates someday.

 

[Rick Ankrum]

Leo Lichtman wrote:
> "Fritz M" wrote: I would think the centripetal force of the rotating tire
> might overcome any "jostling" of the molecules that comes from riding on
> rough pavement. (clip)
> ^^^^^^^^^^^^^^^
> There could be some effect of centripetal force (or centrifugal force,
> depending on how "sophisticated" you want to sound,) but please bear in mind
> that the portion of the tire at the bottom, where the jostling is taking
> place is STATIONARY. There must be some degree of roughness at which the
> rotational forces equal the mixing forces. For higher roughness, the air
> would remain mixed, and for lower roughness, segregation would progress.
>
>
Are you saying my miles on the trainer(with a smooth roller) would
extend the time period between air evacuation events?

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[Bill Sornson]

Rick Ankrum wrote:

> Are you saying my miles on the trainer(with a smooth roller) would
> extend the time period between air evacuation events?

Depends on your pre-workout meal.

Gift for the obvious (and crass), BS

 

[The Wogster]

Rick Ankrum wrote:
>
>
> With all the talk of greenhouse gases I am concerned with having tired
> air in my bike tubes. How long can I can go between evacuating the air
> and putting new air in? I am afraid that the air molecules will all be
> pushed to the outer edge of the tire if I do not evacuate the tubes on a
> regular basis. This could cause the tire to put too much weight on the
> road and thus I am not be able to get at top speed quickly.
>
> Does tapping on the tread move the molecules back into the center of the
> tube?
>

I have gone 4 or 5 years with some of the same air in a tire, tired air
doesn't hold as much pressure, so your tires will go flat after a while,
however new air will often rejuvenate the old air to some degree, so it
often doesn't take much to build back full pressure.

Then again some of the new air, is more polluted then the old air, and
polluted air, is heavier then non-polluted air, so, the air in your
tires is probably lighter then the air you can put in.....

W

 

[JJ]

"Bonehenge" <[email protected]> wrote in message
news:[email protected]...
> On Sat, 02 Jul 2005 22:31:13 -0500, Rick Ankrum
> <[email protected]> wrote:
>
>>
>>Does tapping on the tread move the molecules back into the center of the
>>tube?
>
> Air is cheap enough, and recyclable, so I simply replace mine on a
> regular schedule.
>
> Soon, I'll be marketing a "Used tire air recovery and recycling kit",
> so the old air isn't directly vented to the atmosphere. You can't be
> too careful these days. The kit will redistribute the molecules
> evenly, making the air suitable for reuse.
>
> Hands off, SHELBROCO! The recovery kit is already patent pending!
> <G>

Another very good reason to lobby your representative for EPA mandates and
gov't funding for airless tire development. A mere 10 billion or so should
get this worthwhile program started.

 

[Leo Lichtman]

"The Wogster" wrote: clip) so, the air in your tires is probably lighter
then the air you can put in.....
^^^^^^^^^^^^^^^
If you are really serious about this, take your bike to a mountain top and
inflate the tires there.

 

[The Wogster]

Leo Lichtman wrote:
> "The Wogster" wrote: clip) so, the air in your tires is probably lighter
> then the air you can put in.....
> ^^^^^^^^^^^^^^^
> If you are really serious about this, take your bike to a mountain top and
> inflate the tires there.
>
>
Kinda difficult around here, considering the current smog advisory,
that's largely do to Ohio, Michigan and Pennsylvania pollution, covers
many areas where traditionally you could find clear air.

W

 

[Arthur Harris]

"Rick Ankrum" wrote:
> With all the talk of greenhouse gases I am concerned with having tired air
> in my bike tubes. How long can I can go between evacuating the air and
> putting new air in?

Twice a year should do. As a minimum you want to replace the air in late
fall and early spring. And most important, don't store the bike bike hanging
it from its rims.

Art Harris

 

[wvantwiller]

Rick Ankrum <[email protected]> wrote in
news:[email protected]:

>
>
> With all the talk of greenhouse gases I am concerned with having tired
> air in my bike tubes. How long can I can go between evacuating the air
> and putting new air in? I am afraid that the air molecules will all be
> pushed to the outer edge of the tire if I do not evacuate the tubes on
> a regular basis. This could cause the tire to put too much weight on
> the road and thus I am not be able to get at top speed quickly.
>
> Does tapping on the tread move the molecules back into the center of
> the tube?
>
> 9-)

If you're not using nitrogen as a filler gas you run the risk of serious
thermal expansion problems at higher speeds.

You should evacuate and refill whenever your routine samples show below 79
v/o N2 in the tube.

A physical sign of this would be when you get a distinct thump every
revolution at the position of the valve stem if you use prestas that have
the valve stem restraints on the inner rim. The rest of the tube is not so
restrained, so with all the molecules at the periphery they will radially
expand the tube against the holding force of the tire beads/carcass; the
valve is a point source of greater restraint, though, and will be somewhat
less radially deflected.

 

[[email protected]]

>You should evacuate and refill whenever your routine samples show below
>79 v/o N2 in the tube.
You want to use helium to reduce weight and top off daily.
Enen though hydrogen is lighter, would it cause destructive chemical
reactions?

 

[Rick Ankrum]

wvantwiller wrote:
> Rick Ankrum <[email protected]> wrote in
> news:[email protected]:
>
>
>>
>>
>>With all the talk of greenhouse gases I am concerned with having tired
>>air in my bike tubes. How long can I can go between evacuating the air
>>and putting new air in? I am afraid that the air molecules will all be
>>pushed to the outer edge of the tire if I do not evacuate the tubes on
>>a regular basis. This could cause the tire to put too much weight on
>>the road and thus I am not be able to get at top speed quickly.
>>
>>Does tapping on the tread move the molecules back into the center of
>>the tube?
>>
>>9-)
>
>
> If you're not using nitrogen as a filler gas you run the risk of serious
> thermal expansion problems at higher speeds.
>
> You should evacuate and refill whenever your routine samples show below 79
> v/o N2 in the tube.
>
> A physical sign of this would be when you get a distinct thump every
> revolution at the position of the valve stem if you use prestas that have
> the valve stem restraints on the inner rim. The rest of the tube is not so
> restrained, so with all the molecules at the periphery they will radially
> expand the tube against the holding force of the tire beads/carcass; the
> valve is a point source of greater restraint, though, and will be somewhat
> less radially deflected.
Will the closing torque on the presta valve make a difference? What is
the correct presta valve torque?

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[LioNiNoiL_a t_Y a h 0 0_d 0 t_c 0 m]

Mike.A.Schwab wrote:

> You want to use helium to reduce weight and top off daily.

Yes, but not just any old helium: for the utmost in weight reduction,
knowledgeable riders use helium-3, which is 25% lighter than the more
common and less desireable helium-4.

> Enen though hydrogen is lighter, would it cause destructive
> chemical reactions?

Yes, especially where there is a source of ignition nearby.

--
"Bicycling is a healthy and manly pursuit with much
to recommend it, and, unlike other foolish crazes,
it has not died out." -- The Daily Telegraph (1877)

 

[Leo Lichtman]

<[email protected]> wrote: (clip) Enen though hydrogen is lighter,
would it cause destructive chemical reactions?
^^^^^^^^^^^^^^^
In discussions about the advantages (or futility) of filling tires with
nitrogen, it has been established that oxygen can diffuse through the rubber
tube wall. If you filled with hydrogen, would oxygen diffuse inward? The
partial pressure of O2 outside the tube is greater than that inside. Could
this lead to a hazardous mixture?