Lots of variables, Eric. You are wise to verify. Even altitude will vary air pressure and road temperature. We always had someone at pit out, to verify tire temps with an IR Gun.
One thing I always remind others, is to be careful where you check your air pressure and make sure you keep caps on the valve stems. The reason is that dust, debris and dirt can lodge in the valve stem and be forced into the stem when airing up. I always carry a supply of valve stems and more than one stem remover and caps. Also, most cigarette air compressors will not inflate a 19.5" tire to a safe inflation level. Be sure to check your auxillary
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