car tire pressure...
 

drops when it gets cold out right?

Both the pressure you *should* run them at , and the pressure they do run at should drop (i think).

Soft tyres grip easier in the winter, and cooler air has less pressure.

Yes, unless you fill them with nitrogen.

measure the pressure after you have driven them, as heat expands

What do you put in there? Most people use 70% nitrogen.

I just had a tire trigger the tire pressure sensor by being over inflated and it is colder then hell here. No idea what he problem is but it was at 40 lbs.

think i'll have to put some air in, they're dropping pretty low. Pizza delivery guy tipped us off to it. I never noticed it was as bad as it is until now.

On the drivers door pillar of most cars is an info sticker with recommended tire pressure. This is specified to be checked when the tires are cold.