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What exactly does cold pressure mean?
I help maintain a Ford E350 used for a vanpool.
The door panel spec says that the rear tires require 80 psi. The sidewall specs on the rear tires say that the maximum pressure is 80 psi. So, what does cold pressure mean exactly? If I check the tires on a cold morning (say 35 degrees) I will end up putting in a few extra pounds more that I would at 70 degrees. But I bet the operating temperature of a tire is largely independent of whether the ambient temperature is 35 or 70. |
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#2
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What exactly does cold pressure mean?
"Tom Adams" > wrote in message ... >I help maintain a Ford E350 used for a vanpool. > > The door panel spec says that the rear tires require 80 psi. > > The sidewall specs on the rear tires say that the maximum pressure is > 80 psi. > > So, what does cold pressure mean exactly? > > If I check the tires on a cold morning (say 35 degrees) I will end up > putting in a few extra pounds more that I would at 70 degrees. But I > bet the operating temperature of a tire is largely independent of > whether the ambient temperature is 35 or 70. The difference in pressure between 35F and 70F is no more than about 3-4 psi. The "cold" pressure to be that which is measured on a tire which is has not been heated by road use. It is the ambiental temperature whether it is 35F or 70F. |
#3
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What exactly does cold pressure mean?
On Nov 29, 4:12*pm, "hls" > wrote:
> "Tom Adams" > wrote in message > > ... > > >I help maintain a Ford E350 used for a vanpool. > > > The door panel spec says that the rear tires require 80 psi. > > > The sidewall specs on the rear tires say that the maximum pressure is > > 80 psi. > > > So, what does cold pressure mean exactly? > > > If I check the tires on a cold morning (say 35 degrees) I will end up > > putting in a few extra pounds more that I would at 70 degrees. * But I > > bet the operating temperature of a tire is largely independent of > > whether the ambient temperature is 35 or 70. > > The difference in pressure between 35F and 70F is no more than about > 3-4 psi. > > The "cold" pressure to be that which is measured on a tire which is > has not been heated by road use. * It is the ambiental temperature > whether it is 35F or 70F. Seems like that 3-4 psi would lead to a higher operating temperature and pressure when you got up to speed and fully warmed up the tire. Correct? Are you saying that should be ignored even when you are operating at the maximum pressure specified on the tire wall? |
#4
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What exactly does cold pressure mean?
"Tom Adams" > wrote in message ... On Nov 29, 4:12 pm, "hls" > wrote: > "Tom Adams" > wrote in message > > ... > > >I help maintain a Ford E350 used for a vanpool. > > > The door panel spec says that the rear tires require 80 psi. > > > The sidewall specs on the rear tires say that the maximum pressure is > > 80 psi. > > > So, what does cold pressure mean exactly? > > > If I check the tires on a cold morning (say 35 degrees) I will end up > > putting in a few extra pounds more that I would at 70 degrees. But I > > bet the operating temperature of a tire is largely independent of > > whether the ambient temperature is 35 or 70. > > The difference in pressure between 35F and 70F is no more than about > 3-4 psi. > > The "cold" pressure to be that which is measured on a tire which is > has not been heated by road use. It is the ambiental temperature > whether it is 35F or 70F. Seems like that 3-4 psi would lead to a higher operating temperature and pressure when you got up to speed and fully warmed up the tire. Correct? Are you saying that should be ignored even when you are operating at the maximum pressure specified on the tire wall? I didnt say you should ignore anything. If the tire is specified at 80 psi max COLD, then that is what it means. The pressure will rise as the tire heats up, but then that is not a cold pressure reading. If you are going to be on the highway, then you can stop and measure the hot pressure when you fuel. You can reduce them to 80PSI if you tire says 80psi maximum pressure. |
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What exactly does cold pressure mean?
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#6
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What exactly does cold pressure mean?
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#7
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What exactly does cold pressure mean?
Tom Adams wrote:
> I help maintain a Ford E350 used for a vanpool. > > The door panel spec says that the rear tires require 80 psi. That is great IF the tires on the van are the same ones that came from the factory. Otherwise it's basically crap. > > The sidewall specs on the rear tires say that the maximum pressure is > 80 psi. And what does the chart for that tire say the operating pressure should be given the load you carry? If your not driving around at the GVW all day then you probably also don't need the maximum pressure. > > So, what does cold pressure mean exactly? Cold pressure means NO drive time on the tire. What it reads after the van has sat long enough for the tires to reach ambient air temperature. So you come out in the AM, Start the engine so it warms up and check the tire air pressure. (Don't forget to check the spare) > > If I check the tires on a cold morning (say 35 degrees) I will end up > putting in a few extra pounds more that I would at 70 degrees. But I > bet the operating temperature of a tire is largely independent of > whether the ambient temperature is 35 or 70. That is why you check the pressure at whatever the "normal" temp is for the given season. So if you normally see 35-40 degrees during the winter check it at 37 degrees. The small amount of change won't make much difference. Same in the spring and summer. If the "normal" temps are around 80 degrees then check it at that temp. -- Steve W. |
#8
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What exactly does cold pressure mean?
On 11/29/2010 06:57 PM, Steve W. wrote:
> Tom Adams wrote: >> I help maintain a Ford E350 used for a vanpool. >> >> The door panel spec says that the rear tires require 80 psi. > > That is great IF the tires on the van are the same ones that came from > the factory. Otherwise it's basically crap. well, it might be crap for the tire, but it's not for the van's stability. you certainly don't want the pressure to be less than that if it's loaded - and vanpools usually are. > >> >> The sidewall specs on the rear tires say that the maximum pressure is >> 80 psi. > > And what does the chart for that tire say the operating pressure should > be given the load you carry? If your not driving around at the GVW all > day then you probably also don't need the maximum pressure. > >> >> So, what does cold pressure mean exactly? > > Cold pressure means NO drive time on the tire. What it reads after the > van has sat long enough for the tires to reach ambient air temperature. > So you come out in the AM, Start the engine so it warms up and check the > tire air pressure. (Don't forget to check the spare) > >> >> If I check the tires on a cold morning (say 35 degrees) I will end up >> putting in a few extra pounds more that I would at 70 degrees. But I >> bet the operating temperature of a tire is largely independent of >> whether the ambient temperature is 35 or 70. > > That is why you check the pressure at whatever the "normal" temp is for > the given season. So if you normally see 35-40 degrees during the winter > check it at 37 degrees. The small amount of change won't make much > difference. > > Same in the spring and summer. If the "normal" temps are around 80 > degrees then check it at that temp. > -- nomina rutrum rutrum |
#9
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What exactly does cold pressure mean?
jim beam wrote:
> On 11/29/2010 06:57 PM, Steve W. wrote: >> Tom Adams wrote: >>> I help maintain a Ford E350 used for a vanpool. >>> >>> The door panel spec says that the rear tires require 80 psi. >> >> That is great IF the tires on the van are the same ones that came from >> the factory. Otherwise it's basically crap. > > well, it might be crap for the tire, but it's not for the van's > stability. you certainly don't want the pressure to be less than that > if it's loaded - and vanpools usually are. > > No it is crap all around. That number is based on the OEM tire and GVW. It is only valid for the same tire. Say I buy the same van, Say it comes OEM with a 245 75 16. So I decide to replace the tires with something like a 265 35 20 (or whatever fits in the rubber band sizes). Does the tire pressure apply? NOPE. Noww if the tire is the same ply rating, same type of construction and same size as OEM then it could be used as a guide IF those tires are rated the same way. -- Steve W. (\___/) (='.'=) (")_(") |
#10
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What exactly does cold pressure mean?
On 11/29/2010 08:23 PM, Steve W. wrote:
> jim beam wrote: >> On 11/29/2010 06:57 PM, Steve W. wrote: >>> Tom Adams wrote: >>>> I help maintain a Ford E350 used for a vanpool. >>>> >>>> The door panel spec says that the rear tires require 80 psi. >>> >>> That is great IF the tires on the van are the same ones that came from >>> the factory. Otherwise it's basically crap. >> >> well, it might be crap for the tire, but it's not for the van's >> stability. you certainly don't want the pressure to be less than that >> if it's loaded - and vanpools usually are. >> >> > > No it is crap all around. That number is based on the OEM tire and GVW. > It is only valid for the same tire. > > Say I buy the same van, Say it comes OEM with a 245 75 16. So I decide > to replace the tires with something like a 265 35 20 (or whatever fits > in the rubber band sizes). don't be ridiculous - nobody's going to be monkeying about with non-stock wheels on an f350 carpool. > Does the tire pressure apply? NOPE. same pressures apply - see above. > > Noww if the tire is the same ply rating, same type of construction and > same size as OEM then it could be used as a guide IF those tires are > rated the same way. > > -- nomina rutrum rutrum |
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