Tire pressure
#51
Guest
Posts: n/a
Re: Tire pressure
billy ray wrote:
> Air pressure in a tire is directly proportional to temperature. In the
> absence of other forces, you will gain or lose about 1 psi for every 10
> degrees (F) temperature change.
I was a little surprised by that effect. Aired up to 28psi after a
day's wheelin', temps in the high eighties. Drove home (same
elevation) and the next morning (60s) they were all @ 23psi.
#52
Guest
Posts: n/a
Re: Tire pressure
billy ray wrote:
> Air pressure in a tire is directly proportional to temperature. In the
> absence of other forces, you will gain or lose about 1 psi for every 10
> degrees (F) temperature change.
I was a little surprised by that effect. Aired up to 28psi after a
day's wheelin', temps in the high eighties. Drove home (same
elevation) and the next morning (60s) they were all @ 23psi.
#53
Guest
Posts: n/a
Re: Tire pressure
Yeah, but I always wondered about places like the high desert where
daytime can be 100 and nights can be 60. It would seem that the
differential between these extremes could cause a tire that was inflated
to proper pressure at 5 AM to be seriously overinflated by 4 PM.
Any thoughts?
DAve
mabar wrote:
> And "cold does not mean cold daytime temperatures. "Cold" means not having
> been driven for at least a few hours. For example: you could check your
> tires when "cold" on a 95 degree Florida day.
>
> Tom
>
>
> "Mike Romain" <romainm@sympatico.ca> wrote in message
> news:453D163E.5D5B5CBF@sympatico.ca...
>> The owners manual says to check them cold. No matter the time of
>> year....
>>
>> Mike
>> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
>> 88 Cherokee 235 BFG AT's
>> Canadian Off Road Trips Photos: Non members can still view!
>> Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
>> (More Off Road album links at bottom of the view page)
>>
>
>
daytime can be 100 and nights can be 60. It would seem that the
differential between these extremes could cause a tire that was inflated
to proper pressure at 5 AM to be seriously overinflated by 4 PM.
Any thoughts?
DAve
mabar wrote:
> And "cold does not mean cold daytime temperatures. "Cold" means not having
> been driven for at least a few hours. For example: you could check your
> tires when "cold" on a 95 degree Florida day.
>
> Tom
>
>
> "Mike Romain" <romainm@sympatico.ca> wrote in message
> news:453D163E.5D5B5CBF@sympatico.ca...
>> The owners manual says to check them cold. No matter the time of
>> year....
>>
>> Mike
>> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
>> 88 Cherokee 235 BFG AT's
>> Canadian Off Road Trips Photos: Non members can still view!
>> Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
>> (More Off Road album links at bottom of the view page)
>>
>
>
#54
Guest
Posts: n/a
Re: Tire pressure
Yeah, but I always wondered about places like the high desert where
daytime can be 100 and nights can be 60. It would seem that the
differential between these extremes could cause a tire that was inflated
to proper pressure at 5 AM to be seriously overinflated by 4 PM.
Any thoughts?
DAve
mabar wrote:
> And "cold does not mean cold daytime temperatures. "Cold" means not having
> been driven for at least a few hours. For example: you could check your
> tires when "cold" on a 95 degree Florida day.
>
> Tom
>
>
> "Mike Romain" <romainm@sympatico.ca> wrote in message
> news:453D163E.5D5B5CBF@sympatico.ca...
>> The owners manual says to check them cold. No matter the time of
>> year....
>>
>> Mike
>> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
>> 88 Cherokee 235 BFG AT's
>> Canadian Off Road Trips Photos: Non members can still view!
>> Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
>> (More Off Road album links at bottom of the view page)
>>
>
>
daytime can be 100 and nights can be 60. It would seem that the
differential between these extremes could cause a tire that was inflated
to proper pressure at 5 AM to be seriously overinflated by 4 PM.
Any thoughts?
DAve
mabar wrote:
> And "cold does not mean cold daytime temperatures. "Cold" means not having
> been driven for at least a few hours. For example: you could check your
> tires when "cold" on a 95 degree Florida day.
>
> Tom
>
>
> "Mike Romain" <romainm@sympatico.ca> wrote in message
> news:453D163E.5D5B5CBF@sympatico.ca...
>> The owners manual says to check them cold. No matter the time of
>> year....
>>
>> Mike
>> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
>> 88 Cherokee 235 BFG AT's
>> Canadian Off Road Trips Photos: Non members can still view!
>> Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
>> (More Off Road album links at bottom of the view page)
>>
>
>
#55
Guest
Posts: n/a
Re: Tire pressure
Yeah, but I always wondered about places like the high desert where
daytime can be 100 and nights can be 60. It would seem that the
differential between these extremes could cause a tire that was inflated
to proper pressure at 5 AM to be seriously overinflated by 4 PM.
Any thoughts?
DAve
mabar wrote:
> And "cold does not mean cold daytime temperatures. "Cold" means not having
> been driven for at least a few hours. For example: you could check your
> tires when "cold" on a 95 degree Florida day.
>
> Tom
>
>
> "Mike Romain" <romainm@sympatico.ca> wrote in message
> news:453D163E.5D5B5CBF@sympatico.ca...
>> The owners manual says to check them cold. No matter the time of
>> year....
>>
>> Mike
>> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
>> 88 Cherokee 235 BFG AT's
>> Canadian Off Road Trips Photos: Non members can still view!
>> Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
>> (More Off Road album links at bottom of the view page)
>>
>
>
daytime can be 100 and nights can be 60. It would seem that the
differential between these extremes could cause a tire that was inflated
to proper pressure at 5 AM to be seriously overinflated by 4 PM.
Any thoughts?
DAve
mabar wrote:
> And "cold does not mean cold daytime temperatures. "Cold" means not having
> been driven for at least a few hours. For example: you could check your
> tires when "cold" on a 95 degree Florida day.
>
> Tom
>
>
> "Mike Romain" <romainm@sympatico.ca> wrote in message
> news:453D163E.5D5B5CBF@sympatico.ca...
>> The owners manual says to check them cold. No matter the time of
>> year....
>>
>> Mike
>> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
>> 88 Cherokee 235 BFG AT's
>> Canadian Off Road Trips Photos: Non members can still view!
>> Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
>> (More Off Road album links at bottom of the view page)
>>
>
>
#56
Guest
Posts: n/a
Re: Tire pressure
"DaveW" <spsffan@verizon.net> wrote in message
news:dKf0h.11010$LA.4573@trnddc06...
> Yeah, but I always wondered about places like the high desert where
> daytime can be 100 and nights can be 60. It would seem that the
> differential between these extremes could cause a tire that was inflated
> to proper pressure at 5 AM to be seriously overinflated by 4 PM.
>
> Any thoughts?
Lookup Boyle's Law... Just remember though that the temperature is
referenced in degrees Kelvin, not Celsius or Fahrenheit... 100F = 38C =
311K... 60F = 16C = 289K... Thus you will have a (311-289)/289 percent
difference (i.e. 7.6%)... If your pressure is at 30psi at 60F, it will be at
32.3psi at 100F... Of course, in this example, I'm assuming that volume
remains constant, but since we're talking about a rubber tire, that's not
exactly true, but it would only add a small change to the result and it
would be a reduction in the percentage anyway...
Yeah, I know that Boyle's Law refers to *ideal* gases and that air is not
one, but it's close enough for what we're talking about here...
news:dKf0h.11010$LA.4573@trnddc06...
> Yeah, but I always wondered about places like the high desert where
> daytime can be 100 and nights can be 60. It would seem that the
> differential between these extremes could cause a tire that was inflated
> to proper pressure at 5 AM to be seriously overinflated by 4 PM.
>
> Any thoughts?
Lookup Boyle's Law... Just remember though that the temperature is
referenced in degrees Kelvin, not Celsius or Fahrenheit... 100F = 38C =
311K... 60F = 16C = 289K... Thus you will have a (311-289)/289 percent
difference (i.e. 7.6%)... If your pressure is at 30psi at 60F, it will be at
32.3psi at 100F... Of course, in this example, I'm assuming that volume
remains constant, but since we're talking about a rubber tire, that's not
exactly true, but it would only add a small change to the result and it
would be a reduction in the percentage anyway...
Yeah, I know that Boyle's Law refers to *ideal* gases and that air is not
one, but it's close enough for what we're talking about here...
#57
Guest
Posts: n/a
Re: Tire pressure
"DaveW" <spsffan@verizon.net> wrote in message
news:dKf0h.11010$LA.4573@trnddc06...
> Yeah, but I always wondered about places like the high desert where
> daytime can be 100 and nights can be 60. It would seem that the
> differential between these extremes could cause a tire that was inflated
> to proper pressure at 5 AM to be seriously overinflated by 4 PM.
>
> Any thoughts?
Lookup Boyle's Law... Just remember though that the temperature is
referenced in degrees Kelvin, not Celsius or Fahrenheit... 100F = 38C =
311K... 60F = 16C = 289K... Thus you will have a (311-289)/289 percent
difference (i.e. 7.6%)... If your pressure is at 30psi at 60F, it will be at
32.3psi at 100F... Of course, in this example, I'm assuming that volume
remains constant, but since we're talking about a rubber tire, that's not
exactly true, but it would only add a small change to the result and it
would be a reduction in the percentage anyway...
Yeah, I know that Boyle's Law refers to *ideal* gases and that air is not
one, but it's close enough for what we're talking about here...
news:dKf0h.11010$LA.4573@trnddc06...
> Yeah, but I always wondered about places like the high desert where
> daytime can be 100 and nights can be 60. It would seem that the
> differential between these extremes could cause a tire that was inflated
> to proper pressure at 5 AM to be seriously overinflated by 4 PM.
>
> Any thoughts?
Lookup Boyle's Law... Just remember though that the temperature is
referenced in degrees Kelvin, not Celsius or Fahrenheit... 100F = 38C =
311K... 60F = 16C = 289K... Thus you will have a (311-289)/289 percent
difference (i.e. 7.6%)... If your pressure is at 30psi at 60F, it will be at
32.3psi at 100F... Of course, in this example, I'm assuming that volume
remains constant, but since we're talking about a rubber tire, that's not
exactly true, but it would only add a small change to the result and it
would be a reduction in the percentage anyway...
Yeah, I know that Boyle's Law refers to *ideal* gases and that air is not
one, but it's close enough for what we're talking about here...
#58
Guest
Posts: n/a
Re: Tire pressure
"DaveW" <spsffan@verizon.net> wrote in message
news:dKf0h.11010$LA.4573@trnddc06...
> Yeah, but I always wondered about places like the high desert where
> daytime can be 100 and nights can be 60. It would seem that the
> differential between these extremes could cause a tire that was inflated
> to proper pressure at 5 AM to be seriously overinflated by 4 PM.
>
> Any thoughts?
Lookup Boyle's Law... Just remember though that the temperature is
referenced in degrees Kelvin, not Celsius or Fahrenheit... 100F = 38C =
311K... 60F = 16C = 289K... Thus you will have a (311-289)/289 percent
difference (i.e. 7.6%)... If your pressure is at 30psi at 60F, it will be at
32.3psi at 100F... Of course, in this example, I'm assuming that volume
remains constant, but since we're talking about a rubber tire, that's not
exactly true, but it would only add a small change to the result and it
would be a reduction in the percentage anyway...
Yeah, I know that Boyle's Law refers to *ideal* gases and that air is not
one, but it's close enough for what we're talking about here...
news:dKf0h.11010$LA.4573@trnddc06...
> Yeah, but I always wondered about places like the high desert where
> daytime can be 100 and nights can be 60. It would seem that the
> differential between these extremes could cause a tire that was inflated
> to proper pressure at 5 AM to be seriously overinflated by 4 PM.
>
> Any thoughts?
Lookup Boyle's Law... Just remember though that the temperature is
referenced in degrees Kelvin, not Celsius or Fahrenheit... 100F = 38C =
311K... 60F = 16C = 289K... Thus you will have a (311-289)/289 percent
difference (i.e. 7.6%)... If your pressure is at 30psi at 60F, it will be at
32.3psi at 100F... Of course, in this example, I'm assuming that volume
remains constant, but since we're talking about a rubber tire, that's not
exactly true, but it would only add a small change to the result and it
would be a reduction in the percentage anyway...
Yeah, I know that Boyle's Law refers to *ideal* gases and that air is not
one, but it's close enough for what we're talking about here...
#59
Guest
Posts: n/a
Re: Tire pressure
Mark:
If you aired up to 28lbs after a day's wheelin', then the tires weren't
"cold."
"Cold" means not having been driven for at least a few hours.
Tom
"Mark" <axolotl73@hotmail.com> wrote in message
news:1161922204.827204.192760@m7g2000cwm.googlegro ups.com...
>
> billy ray wrote:
> > Air pressure in a tire is directly proportional to temperature. In the
> > absence of other forces, you will gain or lose about 1 psi for every 10
> > degrees (F) temperature change.
>
> I was a little surprised by that effect. Aired up to 28psi after a
> day's wheelin', temps in the high eighties. Drove home (same
> elevation) and the next morning (60s) they were all @ 23psi.
>
If you aired up to 28lbs after a day's wheelin', then the tires weren't
"cold."
"Cold" means not having been driven for at least a few hours.
Tom
"Mark" <axolotl73@hotmail.com> wrote in message
news:1161922204.827204.192760@m7g2000cwm.googlegro ups.com...
>
> billy ray wrote:
> > Air pressure in a tire is directly proportional to temperature. In the
> > absence of other forces, you will gain or lose about 1 psi for every 10
> > degrees (F) temperature change.
>
> I was a little surprised by that effect. Aired up to 28psi after a
> day's wheelin', temps in the high eighties. Drove home (same
> elevation) and the next morning (60s) they were all @ 23psi.
>
#60
Guest
Posts: n/a
Re: Tire pressure
Mark:
If you aired up to 28lbs after a day's wheelin', then the tires weren't
"cold."
"Cold" means not having been driven for at least a few hours.
Tom
"Mark" <axolotl73@hotmail.com> wrote in message
news:1161922204.827204.192760@m7g2000cwm.googlegro ups.com...
>
> billy ray wrote:
> > Air pressure in a tire is directly proportional to temperature. In the
> > absence of other forces, you will gain or lose about 1 psi for every 10
> > degrees (F) temperature change.
>
> I was a little surprised by that effect. Aired up to 28psi after a
> day's wheelin', temps in the high eighties. Drove home (same
> elevation) and the next morning (60s) they were all @ 23psi.
>
If you aired up to 28lbs after a day's wheelin', then the tires weren't
"cold."
"Cold" means not having been driven for at least a few hours.
Tom
"Mark" <axolotl73@hotmail.com> wrote in message
news:1161922204.827204.192760@m7g2000cwm.googlegro ups.com...
>
> billy ray wrote:
> > Air pressure in a tire is directly proportional to temperature. In the
> > absence of other forces, you will gain or lose about 1 psi for every 10
> > degrees (F) temperature change.
>
> I was a little surprised by that effect. Aired up to 28psi after a
> day's wheelin', temps in the high eighties. Drove home (same
> elevation) and the next morning (60s) they were all @ 23psi.
>