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air pressure/altitude

Posted: Tue Dec 18, 2012 4:36 pm
by Bogdan Swider
Anyone know of a formula for how the air pressure in tires is affected by altitude ? I'll soon be going from 6000 feet, Colorado to St.Louis/Chicago - basically sea level. As often as I've done this you'd think I'd have looked into this before. Bogdan

air pressure/altitude

Posted: Tue Dec 18, 2012 5:18 pm
by mark ward
Temps are also an issue. carry a $7-$12. tire gage and check regularly OR As you should anyways. In Death Valley, We went from 291ft BELOW sea level 1day And the next day 6168 above sea level, with out checking etc. Or 12,183 at the park above Estes park. where potato chip bags look like they are about to BURST.
--- On Tue, 12/18/12, Bogdan Swider wrote: From: Bogdan Swider Subject: [DSN_KLR650] Air pressure/altitude To: "Bogdan Swider" , "DSN_KLR650@yahoogroups.com" DSN_KLR650@yahoogroups.com> Date: Tuesday, December 18, 2012, 10:36 PM Anyone know of a formula for how the air pressure in tires is affected by altitude ? I'll soon be going from 6000 feet, Colorado to St.Louis/Chicago - basically sea level. As often as I've done this you'd think I'd have looked into this before. Bogdan [Non-text portions of this message have been removed]

air pressure/altitude

Posted: Tue Dec 18, 2012 5:50 pm
by RobertWichert
Here you go... http://en.wikipedia.org/wiki/File:Atmospheric_Pressure_vs._Altitude.png You have to speak kPa though. Figure 100 kPa is 14.7 psia and you'll be close. Robert Wichert P.Eng. LEED AP BD&C +1 916 966 9060 FAX +1 916 966 9068 ===============================================
On 12/18/2012 3:18 PM, mark ward wrote: > > Temps are also an issue. > > carry a $7-$12. tire gage and check regularly OR As you should anyways. > > In Death Valley, We went from 291ft BELOW sea level 1day And the next > day 6168 above sea level, with out checking etc. > > Or 12,183 at the park above Estes park. where potato chip bags look > like they are about to BURST. > > --- On Tue, 12/18/12, Bogdan Swider > wrote: > > From: Bogdan Swider > > Subject: [DSN_KLR650] Air pressure/altitude > To: "Bogdan Swider" >, "DSN_KLR650@yahoogroups.com > " DSN_KLR650@yahoogroups.com > > > Date: Tuesday, December 18, 2012, 10:36 PM > > > > Anyone know of a formula for how the air pressure in tires is affected by > altitude ? I'll soon be going from 6000 feet, Colorado to St.Louis/Chicago > - basically sea level. As often as I've done this you'd think I'd have > looked into this before. > > Bogdan > > [Non-text portions of this message have been removed] > > [Non-text portions of this message have been removed]

air pressure/altitude

Posted: Tue Dec 18, 2012 5:52 pm
by Jeff Saline
On Tue, 18 Dec 2012 22:36:01 +0000 Bogdan Swider writes:
> > > Anyone know of a formula for how the air pressure in tires is > affected by > altitude ? I'll soon be going from 6000 feet, Colorado to > St.Louis/Chicago > - basically sea level. As often as I've done this you'd think I'd > have > looked into this before. > > Bogdan
<><><><><><> <><><><><><> Bogdan, I don't know of any formula but as has already been stated, temperature is a significant factor. Best, Jeff Saline ABC # 4412 South Dakota Airmarshal Airheads Beemer Club www.airheads.org The Beautiful Black Hills of South Dakota 75 R90/6, 03 KLR650 . . ____________________________________________________________ Woman is 53 But Looks 25 Mom reveals 1 simple wrinkle trick that has angered doctors... http://thirdpartyoffers.juno.com/TGL3141/50d10184d89a91846ac5st02vuc

air pressure/altitude

Posted: Tue Dec 18, 2012 6:03 pm
by mark ward
Remember if you start at 6035ft., 95dig in Colorado springs, and ride to Pikes peak 14,110ft. where it may only be 45dig.
--- On Tue, 12/18/12, RobertWichert wrote: From: RobertWichert Subject: Re: [DSN_KLR650] Air pressure/altitude To: "mark ward" , "klr" DSN_klr650@yahoogroups.com>, "Bogdan Swider" Date: Tuesday, December 18, 2012, 11:50 PM Here you go... http://en.wikipedia.org/wiki/File:Atmospheric_Pressure_vs._Altitude.png You have to speak kPa though. Figure 100 kPa is 14.7 psia and you'll be close. Robert Wichert P.Eng. LEED AP BD&C +1 916 966 9060 FAX +1 916 966 9068 =============================================== On 12/18/2012 3:18 PM, mark ward wrote: > > Temps are also an issue. > > carry a $7-$12. tire gage and check regularly OR As you should anyways. > > In Death Valley, We went from 291ft BELOW sea level 1day And the next > day 6168 above sea level, with out checking etc. > > Or 12,183 at the park above Estes park. where potato chip bags look > like they are about to BURST. > > --- On Tue, 12/18/12, Bogdan Swider > wrote: > > From: Bogdan Swider > > Subject: [DSN_KLR650] Air pressure/altitude > To: "Bogdan Swider" >, "DSN_KLR650@yahoogroups.com > " DSN_KLR650@yahoogroups.com > > > Date: Tuesday, December 18, 2012, 10:36 PM > > > > Anyone know of a formula for how the air pressure in tires is affected by > altitude ? I'll soon be going from 6000 feet, Colorado to St.Louis/Chicago > - basically sea level. As often as I've done this you'd think I'd have > looked into this before. > > Bogdan > > [Non-text portions of this message have been removed] > > [Non-text portions of this message have been removed] [Non-text portions of this message have been removed]

air pressure/altitude

Posted: Tue Dec 18, 2012 6:27 pm
by RobertWichert
Yes, PV=NRT for sure, but altitude alone has some effect. Robert Wichert P.Eng. LEED AP BD&C +1 916 966 9060 FAX +1 916 966 9068 ===============================================
On 12/18/2012 4:03 PM, mark ward wrote: > > Remember if you start at 6035ft., 95dig in Colorado springs, and ride > to Pikes peak 14,110ft. where it may only be 45dig. > > > --- On Tue, 12/18/12, RobertWichert > wrote: > > From: RobertWichert > > Subject: Re: [DSN_KLR650] Air pressure/altitude > To: "mark ward" >, "klr" DSN_klr650@yahoogroups.com > >, "Bogdan Swider" > > > Date: Tuesday, December 18, 2012, 11:50 PM > > > > Here you go... > > http://en.wikipedia.org/wiki/File:Atmospheric_Pressure_vs._Altitude.png > > You have to speak kPa though. Figure 100 kPa is 14.7 psia and you'll > be close. > > Robert Wichert P.Eng. LEED AP BD&C > +1 916 966 9060 > FAX +1 916 966 9068 > > =============================================== > > On 12/18/2012 3:18 PM, mark ward wrote: > > > > Temps are also an issue. > > > > carry a $7-$12. tire gage and check regularly OR As you should anyways. > > > > In Death Valley, We went from 291ft BELOW sea level 1day And the next > > day 6168 above sea level, with out checking etc. > > > > Or 12,183 at the park above Estes park. where potato chip bags look > > like they are about to BURST. > > > > --- On Tue, 12/18/12, Bogdan Swider > > > wrote: > > > > From: Bogdan Swider > > > > > Subject: [DSN_KLR650] Air pressure/altitude > > To: "Bogdan Swider" > > >, "DSN_KLR650@yahoogroups.com > > > " DSN_KLR650@yahoogroups.com > > > > > > Date: Tuesday, December 18, 2012, 10:36 PM > > > > > > > > Anyone know of a formula for how the air pressure in tires is > affected by > > altitude ? I'll soon be going from 6000 feet, Colorado to > St.Louis/Chicago > > - basically sea level. As often as I've done this you'd think I'd have > > looked into this before. > > > > Bogdan > > > > [Non-text portions of this message have been removed] > > > > > > [Non-text portions of this message have been removed] > > [Non-text portions of this message have been removed] > > [Non-text portions of this message have been removed]

air pressure/altitude

Posted: Tue Dec 18, 2012 8:19 pm
by mark ward
Totally agree, I just wanted him to know while he's focusing on going higher may cause the tire to balloon, colder temps will cause (ok a lot of guys here, need it be said) SHRINKAGE. HEY, It's a KLR the "JEEP" of motorcycles. LOL Travel Safe! Travel Well!
--- On Wed, 12/19/12, RobertWichert wrote: From: RobertWichert Subject: Re: [DSN_KLR650] Air pressure/altitude To: "mark ward" Cc: "klr" DSN_klr650@yahoogroups.com>, "Bogdan Swider" Date: Wednesday, December 19, 2012, 12:27 AM Yes, PV=NRT for sure, but altitude alone has some effect. Robert Wichert P.Eng. LEED AP BD&C +1 916 966 9060 FAX +1 916 966 9068 =============================================== On 12/18/2012 4:03 PM, mark ward wrote: > > Remember if you start at 6035ft., 95dig in Colorado springs, and ride > to Pikes peak 14,110ft. where it may only be 45dig. > > > --- On Tue, 12/18/12, RobertWichert > wrote: > > From: RobertWichert > > Subject: Re: [DSN_KLR650] Air pressure/altitude > To: "mark ward" >, "klr" DSN_klr650@yahoogroups.com > >, "Bogdan Swider" > > > Date: Tuesday, December 18, 2012, 11:50 PM > > > > Here you go... > > http://en.wikipedia.org/wiki/File:Atmospheric_Pressure_vs._Altitude.png > > You have to speak kPa though. Figure 100 kPa is 14.7 psia and you'll > be close. > > Robert Wichert P.Eng. LEED AP BD&C > +1 916 966 9060 > FAX +1 916 966 9068 > > =============================================== > > On 12/18/2012 3:18 PM, mark ward wrote: > > > > Temps are also an issue. > > > > carry a $7-$12. tire gage and check regularly OR As you should anyways. > > > > In Death Valley, We went from 291ft BELOW sea level 1day And the next > > day 6168 above sea level, with out checking etc. > > > > Or 12,183 at the park above Estes park. where potato chip bags look > > like they are about to BURST. > > > > --- On Tue, 12/18/12, Bogdan Swider > > > wrote: > > > > From: Bogdan Swider > > > > > Subject: [DSN_KLR650] Air pressure/altitude > > To: "Bogdan Swider" > > >, "DSN_KLR650@yahoogroups.com > > > " DSN_KLR650@yahoogroups.com > > > > > > Date: Tuesday, December 18, 2012, 10:36 PM > > > > > > > > Anyone know of a formula for how the air pressure in tires is > affected by > > altitude ? I'll soon be going from 6000 feet, Colorado to > St.Louis/Chicago > > - basically sea level. As often as I've done this you'd think I'd have > > looked into this before. > > > > Bogdan > > > > [Non-text portions of this message have been removed] > > > > > > [Non-text portions of this message have been removed] > > [Non-text portions of this message have been removed] > > [Non-text portions of this message have been removed] [Non-text portions of this message have been removed]

air pressure/altitude

Posted: Wed Dec 19, 2012 1:19 pm
by Mike Frey
>> Or 12,183 at the park above Estes park. >> where potato chip bags look like they are about to BURST.
Yeah, that's fun in both directions. A Zip-Lock bag, closed up with a half eaten sandwich at 10,000 feet, will look like it's been vacuum sealed if you bring it back down to sea level. Regarding tire pressures - disregarding barometer readings and air temperatures - which, in aviation you just don't do, but in ground based vehicles, it's OK to do - figure that if your tires is inflated to 20 psi at sea level, it will read about 25 psi at 10,000 feet. Conversely, your 20 psi tire at 10,000 feet will read 15 psi when you bring it down to sea level. General (very "general") rule of thumb is: 5 psi increase for every 10,000 foot altitude increase, and 5 psi decrease for every 10,000 foot altitude decrease. Mike On 12/18/2012 6:18 PM, mark ward wrote: > > Temps are also an issue. > > carry a $7-$12. tire gage and check regularly OR As you should anyways. > > In Death Valley, We went from 291ft BELOW sea level 1day And the next > day 6168 above sea level, with out checking etc. > > Or 12,183 at the park above Estes park. where potato chip bags look > like they are about to BURST. > > --- On Tue, 12/18/12, Bogdan Swider > wrote: > > From: Bogdan Swider > > Subject: [DSN_KLR650] Air pressure/altitude > To: "Bogdan Swider" >, "DSN_KLR650@yahoogroups.com > " DSN_KLR650@yahoogroups.com > > > Date: Tuesday, December 18, 2012, 10:36 PM > > > > Anyone know of a formula for how the air pressure in tires is affected by > altitude ? I'll soon be going from 6000 feet, Colorado to St.Louis/Chicago > - basically sea level. As often as I've done this you'd think I'd have > looked into this before. > > Bogdan > > [Non-text portions of this message have been removed] > >

air pressure/altitude

Posted: Wed Dec 19, 2012 9:15 pm
by achesley43@ymail.com
--- In DSN_KLR650@yahoogroups.com, Bogdan Swider wrote:
> > > > Anyone know of a formula for how the air pressure in tires is affected by > altitude ? I'll soon be going from 6000 feet, Colorado to St.Louis/Chicago > - basically sea level. As often as I've done this you'd think I'd have > looked into this before. > > Bogdan >
I made it an effort to check my air pressure in my 1250S Bandit this last summer for one trip , every other day. Leaving home with 38/42 F/R. I even checked it in Glacier Park with snow on both sides of me and again on Mount Evans just for grins. I didn't see anymore than 2 lbs difference on the whole 2 week trip. Never added air. I've done some of the same trips on my KLR but just to Colorado from Louisiana and never got to the point I needed to add or subtract air either. I just really don't think I would worry about it bunches. ;-) Andy whoms been know to be old school. ;-)

air pressure/altitude

Posted: Wed Dec 19, 2012 10:17 pm
by Jud
Altitude/elevation should have no noticeable effect on tire pressure. The tire is essentially a fixed volume. Temperature may play a role, but the air pressure outside the tire does not change the volume inside the tire (except perhaps very slightly), hence, no effect on pressure. You haven't looked into this before because it hasn't been necessary. Jud, who every so often celebrates Boyle's Law and its role in nutrition, motorsports and politics with a Festival of Expanding Gases.
--- In DSN_KLR650@yahoogroups.com, Bogdan Swider wrote: > > > > Anyone know of a formula for how the air pressure in tires is affected by > altitude ? I'll soon be going from 6000 feet, Colorado to St.Louis/Chicago > - basically sea level. As often as I've done this you'd think I'd have > looked into this before. > > Bogdan >