Tires: cold weather tire pressure, psi drop, snow traction

Question
Hi, Should tire pressure be the same in winter as summer?  I know I had correct pressure a few days before we had a sudden cold snap[temperature in the 40's before, dipped down into the teens & lower after]. I lost about 5 lbs in each tire.  Thanks, Jon.

Answer
J Lang,

First, when the temperature drops, the inflation pressure in your tires drops as well, and needs to be refreshed.  The rule of thumb is that for every 10°F drop, 1 psi is lost.

Second, it is not uncommon for leaks to appear that weren't there before when the temperature drops.  Things shrink at different rates, dependent on what they are made out of.  And this is true of tires and rims.

But the inflation pressure is always stated as "cold" - meaning at the current ambient.  So a drop from the 40's  to the teens should have resulted in about 2 psi drop.  

Plus, some folks think that adding a few more psi helps snow traction by concentrating the footprint more allowing the tire to better penetrate through the snow down to the pavement.

Perhaps the best strategy is to use 5 psi more when it is 40°F sand let the outside temperature do its thing.