I’ve installed a lot of tires over the years and always just air them up to the place card, never held them over night to “properly” adjust the air pressure…
If a customer stops in for an alignment, you are supposed to correct the tire pressure before starting, if the tire is hot, just add 2 or 3 psi and it will be correct after cool down (3+ hours or overnight), same with rotates, oil changes, anytime you need to adjust the psi…
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You can tell the engineers here. I just don’t worry much about it. But it was about ten below and we went to a movie. The car normally is in the garage at about 59 degrees. So the tpms showed the tire at about 25 psi after sitting out for a few hours. I added air when I got home. I worry more about losing psi in the winter.
In order to be in sync with the tire pressure monitor, vehicle manufactures suggest using the lowest ambient temperature as a baseline.
Toyota Motors issued a service bulletin with instructions for temperature compensation.
Some of our customers live in Utah, the temperature of the customers destination needs to be considered when adjusting tire pressure.
There is a program on the Toyota TechStream scan tool to assist in temperature/pressure compensation for technician use.
Allow me to clarify:
It matters not whether the at-dawn (coolest/coldest) ambient temperature is F 20 or F 70. That is the coolest part of that day in that part of the world. It’s therefore optimal time to adjust your tires pressures to vehicle specs.
What I’m trying to dispel here is the wide-spread myth that cold means “bone-chilling” or refers to some reference temperature (F 60 or 68 for instance).
Now, the next most optimum time to check/set tire pressures is at least three hours after last driven. If this is at 1 or 3 in the afternoon - the warmest part of most days - and I set my Honda’s tires all to 32psi door frame placard, they are guaranteed to be 1-2psi under-inflated by early next morning (early dawn being my absolute definition of ‘cold/not driven’).
Heh, heh. My car is parked facing south, by 11AM drivers side tires will be warmer than passenger side. Just thought I would add something else to argue about.
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Well, unless Capri states otherwise, I believe the recommended compensation for ‘sunny-side’ tires is 3-4psi.
Or, just drive it off. It will all equal out eventually.
You set your tires to the correct pressure for indoor use. If you use the vehicle outside, you need to inflate the tire pressure in relationship to the outside temperature.
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Correct.
In a nominally heated (F 60) garage, in the dedduh winter, I would add 3-4psi to the cold recommendations on my Honda door frame sticker.
(“dedduh” = 6am on in late January or Feb)
Captain obvious strikes again.
Not sure how you meant that.
Not everyone, especially outside of CarTalk and similar forums, knows about compensating for garage temperature vs indoor when it comes to tire pressures.
What was the point of your story? Did you forget to add air? Many have stated they always adjust tire pressure in preparation for seasonal temperature changes, did the temperature drop 69 degrees in one day during autumn?
Pretty obvious when you go from a 50 degree garage to ten below outside, that you’d need to adjust tire pressure.
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A bit of thread drift here. Anyway, I’ve already gotten what I (as the o.p.) needed here. It almost sounds like you guys are rehashing old arguments, that you can’t resolve to everyone’s satisfaction.
I’m not going to measure tire temperature. If it gets really hot during a long trip, I could stop and measure the pressure. More direct and possibly more accurate, because you don’t have to worry about the difference between internal and external temperature. Plus, a lot of vehicles already have electronic tire pressure monitors - so I assume there is in principle no point to measure temperature, unless you drive very, very fast, or drive in an extremely hot climate (in which case maybe you could get S-rated tires??), hot enough to damage the rubber. (My tire pressure sensors are messed up because the batteries in them have gone bad; it isn’t worth removing the tires to replace the batteries. So my car always flags tire pressure. OK, maybe that disproves my point about tire pressure sensors…)
The only reason I asked about that IR Thermometer, was because I’d like one for other purposes, and that one was a lot cheaper (without shipping) than the Harbor Freight one. Anyway, I’ve heard that for the most accurate measurements you should calibrate IR thermometers by calibrating them to the surface characteristics (I guess color, reflectivity, scattering characteristics, etc. can affect the measurement).
Now if you really want to get fancy, you could design a vehicle that would maintain the desired air pressure on the fly, so it would automatically adjust for changing temperatures. 
Perhaps they already exist in the luxury car market, or the racing market?
Of course that would be more things that can go wrong. Imagine what could happen if the sensor goes bad, and always reads high or low! I believe in simplicity.
Tester
You shouldn’t need to but understand that there is a correlation between high tire temperatures and dry rot (sidewall cracks). Tires flex while in motion, this generates heat within the layers of the tire. Tires with insufficient inflation pressure generate more heat, this accelerates the aging process.
Don’t do that, just be sure the tires are properly inflated before the trip.
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You replace the sensor unit . The batteries are not a replacable item . Just have new ones installed when you buy tires.
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Like i said bing: we know that. But do ordinary every day folk out there know, scrambling maybe two jobs to put food on their family?
People who need their tires to last as long as possible should definitely learn how to properly take care of them.
Why aren’t you setting your tires to 34 PSI in that case?
That technology has already existed for many years on military Humvees. It’s very practical for decreasing tire pressure in certain low traction situations, and then being able to re-inflate them when desired.
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