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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"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.
"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.
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.)
"Rick Ankrum" <[email hidden]> wrote in message news:[email hidden]...
Quoted message said:
8-)
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?
"Rick Ankrum" <[email hidden]> wrote in message news:[email hidden]...
Quoted message said:
8-)
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.
"Rick Ankrum" <[email hidden]> wrote in message news:[email hidden]...
Quoted message said:
8-)
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?
Quoted message said:
This is the very reason why I use tubeless tires.
Poor deluded innocent. They use air, too, you know.
"Bill Sornson" <[email hidden]> wrote in message news:[email hidden]...
Quoted message said:
di said:
"Rick Ankrum" <[email hidden]> wrote in message news:[email hidden]...
Quoted message said:
8-)
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?
Quoted message said:
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.
"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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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.....
"Bonehenge" <[email hidden]> wrote in message news:[email hidden]...
Quoted message said:
Rick Ankrum said:
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.
"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" 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.
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.
Rick Ankrum <[email hidden]> wrote in news:[email hidden]:
Quoted message said:
8-)
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.
Rick Ankrum <[email hidden]> wrote in news:[email hidden]:
Quoted message said:
8-)
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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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.
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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)
<[email hidden]> 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?
