is tire pressure indicator not accurate in cold weather or my tire shop install winter tires poorly?

Seems like the one tire might have a leak, which could be poor install or a factory flaw in the tire, or dumb luck and running something over.

Possible they just didn't fill it right? Did it read higher at first?

 

A 45 to 42 difference is not major and could just be the difference in the two gauges.

The 42s are nothing to worry about but the 31 is REALLY bad. Go put a manual guage on the left rear quickly. Agree with the above, either the tire shop incorrectly inflated it, or it has an issue, or you are just the unluckiest person in the world to pick up a puncture in the first 30 minutes of driving a new tire.

 

Of it lost 14psi in a few hours it will be flat before the tire shop opens.
I would check it before driving or you could knock it off the bead damaging the tire and rim.

 

MN Model 3 owner here. Early in the cold season, and after I got my winters put on and mine were a little haywire. I’ve found the sensors to be quite accurate.

I would drive it to the nearest station with air, and put in 45 and verify on all. From Cold. Don’t drive a long distance. You should see them hold steady. Obviously if PSI drops significantly, then bring to the shop. Keep in mind, average is 1psi per 10 degrees of cooling.

 

It's not uncommon to have a leak at one of the TPMS sensors, so that could be why you're down to 31.

 

Or get a good bike pump - wouldn’t do it from flat, but adding a few psi isn’t too bad.

there are also lots of 12v compressors available. Although, from my experience, tend to wear out quickly.

 

I had a leak in one of the tires of my Model 3 for like 6 months. It was a slow leak and I was too lazy to take it to fix. So it would leak like 3 PSI per week. And I bought this to pump it back up every week:
https://www.amazon.com/gp/product/B07JC8MB1T/

It works great and the digital gauge on it is accurate. I fixed the tire a few months ago and now I just use it to pump up the tires when it get colder and colder. I just keep it in the frunk.

 

Probably leaking at the valve or something. Since they installed the tires, they should fix it for free... unless it is a nail. At my local tire shops, they fix nails for free too even if you don't buy the tire there. They gather goodwill for future business.

 

Definitely should be checked.

 

LOL, that tire pump has a "unique" legal disclaimer!

 

LOL. Looks like they put the disclaimer on the wrong product. On their Snow Foam Cannon page, they are missing this disclaimer. But watering flowers and bathing dogs? Hmmmm....

 

If it read 31 before, and 30.7 now, it could be anything from temperatire-based variance, or noise margin of the reading.

31 isn't the end of the world.

Go to a gas station. Pump all tires equally. (Ideally, double check with a quality gauge). Reset TPMS in the computer. Then check again in a day

 

I'll take my payment in bitcoins, thanks

 

what was teh temp in the shop vs outside air? As a general rule, the tire pressure will drop 1 lb for every 10 degrees (F). (sorry, you'll have to do the conversion to C). For example, if the shop was say 50F degrees and you drove outside into 20F degrees, you'd immediately experience a 3 lb pressure drop in tire air pressure.