|
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. |
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. |
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) >> > > |
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) >> > > |
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) >> > > |
Re: Tire pressure
"DaveW" <spsffan@verizon.net> wrote in message
news:dKf0h.11010$LA.4573@trnddc06... > Yeah, but I always wondered about places like the high desert where > daytime can be 100 and nights can be 60. It would seem that the > differential between these extremes could cause a tire that was inflated > to proper pressure at 5 AM to be seriously overinflated by 4 PM. > > Any thoughts? Lookup Boyle's Law... Just remember though that the temperature is referenced in degrees Kelvin, not Celsius or Fahrenheit... 100F = 38C = 311K... 60F = 16C = 289K... Thus you will have a (311-289)/289 percent difference (i.e. 7.6%)... If your pressure is at 30psi at 60F, it will be at 32.3psi at 100F... Of course, in this example, I'm assuming that volume remains constant, but since we're talking about a rubber tire, that's not exactly true, but it would only add a small change to the result and it would be a reduction in the percentage anyway... Yeah, I know that Boyle's Law refers to *ideal* gases and that air is not one, but it's close enough for what we're talking about here... |
Re: Tire pressure
"DaveW" <spsffan@verizon.net> wrote in message
news:dKf0h.11010$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... |
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... |
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. > |
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. > |
| All times are GMT -4. The time now is 02:30 PM. |
© 2024 MH Sub I, LLC dba Internet Brands