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Cars have tire pressure sensors. So do bicycles; they're called potholes[/caption]
The last two spells of cold weather weren't very demanding or difficult to cope with, but they did have their curious moments.
For instance, take the micro-leak I had in in one of my bicycle tires -- please (Ba-dum!).
At 9° C -- this morning's temperature -- I could expect the tire to leak out in about seven hours. But, at -6° C it didn't appreciably leak at all. Even at 0° C it only lost about 10 pounds of pressure in about three days.
I realize there is an interrelationship between air pressure, temperature and density; there's a higher density of air at the bottom of the gravity well, and higher temperatures mean more energetic molecular movement which means higher air pressure.
So I understand that as the temperature drops so does tire pressure. But what I clearly don't understand is the mechanics of the differential between the air temperature and pressure in a tire versus the ambient outside air.
If I have a slow-leaking tire -- fully inflated -- in sub-zero weather, I would think the pressure and temperature is higher inside the tire than outside. I would expect the tire to leak faster to equalize with the outside lower pressure until an equilibrium is achieved.
I must have everything backwards; if the ambient outside air pressure was higher than inside the tire then I would not expect the tire to leak, but I don't see how that could be in in minus degree weather.
Unless the point is that all air pressure is lower in sub-zero temperatures and less energy means less leaking, period.
Ah well, another thing I don't understand. So deflating, ego-wise.
Cars have tire pressure sensors. So do bicycles; they're called potholes[/caption]The last two spells of cold weather weren't very demanding or difficult to cope with, but they did have their curious moments.
For instance, take the micro-leak I had in in one of my bicycle tires -- please (Ba-dum!).
At 9° C -- this morning's temperature -- I could expect the tire to leak out in about seven hours. But, at -6° C it didn't appreciably leak at all. Even at 0° C it only lost about 10 pounds of pressure in about three days.
I realize there is an interrelationship between air pressure, temperature and density; there's a higher density of air at the bottom of the gravity well, and higher temperatures mean more energetic molecular movement which means higher air pressure.
So I understand that as the temperature drops so does tire pressure. But what I clearly don't understand is the mechanics of the differential between the air temperature and pressure in a tire versus the ambient outside air.
If I have a slow-leaking tire -- fully inflated -- in sub-zero weather, I would think the pressure and temperature is higher inside the tire than outside. I would expect the tire to leak faster to equalize with the outside lower pressure until an equilibrium is achieved.
I must have everything backwards; if the ambient outside air pressure was higher than inside the tire then I would not expect the tire to leak, but I don't see how that could be in in minus degree weather.
Unless the point is that all air pressure is lower in sub-zero temperatures and less energy means less leaking, period.
Ah well, another thing I don't understand. So deflating, ego-wise.
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