Check tire pressure cold or hot?

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Always cold... if you set to proper pressure warm, the pressure in them will drop when they cool, and they'll be underinflated. Let them sit for a few hours, then check and adjust. First thing in the morning is ideal.
 
I've found that tire pressures, at least for me, don't go up by more than 2 psi during short-trip city driving.

So I just fill them up whenever, by setting them to my desired pressure + 2.
 
Cold. That's what both the vehicle and tire manufacturers recommend.

The issue with hot is...how hot? city driving? Highway? Spirited cornering? What would the pressure be for each of those conditions? How accurate would your assessment of stress on the tire be? IF you're racing and have a pyrometer to measure tread temperature for that car, the particular suspension settings, on that track, with that day's weather...OK, then set them hot.

Street? Cold.
 
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I know the manufacturer of the vehicle usually has a sticker or something on the door jam stating the recommended pressures, then there are the pressures molded on the tire side wall which is usually the max pressure for the tire itself. Some will say "Cold" right on the tire. At least that's what I think I saw on one of my motorcycle tires.
 
^^^ Don't know about the craftsman digital, but I have 5 stand-alone gauges in the garaged. Every time I bring home a new gauge, I check it compared to what I have. If it doesn't read about the same as others, I don't use it. Its like culling the bad and keep the good. I have 4 analog (needle) and 1 digital that all look like they read the same. I also have one on the compressor air chuck (analog needle) but it reads about 5 psi low compared to my other gauges in the range of checking tire pressures.
Its like buying a thermometer, I'll check several. Every once in awhile I'll run across one in the bunch that doesn't read like the others, so I'll pick one that reads like the majority. Kind of a risk/chance when it comes to buying a tire gauge I guess.
Higher quality gauges probably have a tighter manufacturing specification, just hope the quality control is on top of things too. I just don't know much about the digital. I don't know what make my digital is, but I know its not craftsman.
 
Originally Posted By: ChuckBerry
I have read that the needle type gauges are most accurate, I have one I have been using for years.

Cold, btw.

Good to know
I like the needle indicated gauge the best. Although I have 1 digital, I won't take it with me when traveling because sure enough when I may really need it, the battery will give up.
Although they have gauges (needle) for something like $2.99, spend the extra - worth it to me anyway. I think I paid around $18 for the last needle indicated gauge I bought. It has a gold anodized housing and a Nascar finish flags silk finish on the indicator face - that's probably why I bought it back then.

Forgot - my portable compressors have a needle pressure indicator too. And I have 1 pencil type (not used) that came with my motorcycle Slime Compact Compressor kit - But I carry CO2 air kit now and have included a dial needle type gauge in the kit.
 
I am pretty sure $2 needle tire pressure guage is not accurate. in this case, craftsman digital guage is better than $2 guage.
 
Also, you may want to air up your tires at the coldest part of the day while out of direct sunlight.

My doorjamb states check cold, but if checking hot add 4psi. Probably not a bad idea in the summer months. Just last week (in 40F temps) I took a 100 mile trip then checked my psi and they were exactly as I had checked them in the morning before driving.

In the summer months, you may wish to allow your motorbike or car set for 3-4 hours after being on the road to get a true ambient reading.
 
Just follow the "3/30" rule: Check tire pressure and/or add air only if you've driven your vehicle to the gas station less than three miles away from home, and going at less than 30 MPH. Can't go wrong with that formula I learned years ago, dude!
______________________________
Flawless '04 350Z Touring Coupe!
 
Overnight before the sun gets to them is a good practical time to check the tires.
Like valve adjustments, I prefer cold . Hot can vary too much. What is warm/hot/whatever?

But checking tires hot after a highway drive will provide good info. You can see what's up.
Often a too LOW cold pressure will cause HOTTER highway temps!
 
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