Low tire pressure light with 20's
 

I just put 20's on my o6' AT. Three days and about 100 miles after I installed them I now have a Low Tire Preasure light on my dash. It blinks for a bit when i turn on the car but then stays on the rest of the time. I checked the tire preassure and it's 40 all around. Any ideas what it could mean?? I used to have a lifted truck so i dont know about these type of things. Thanks

get it recalibarated for the new wheels

Since you have 20's on your car now, you probably don't have the sensors on them? If not, there is your answer. But the light should not stay on on your dash. The only time mine comes on, is ONLY when I drive on the highway for about 45 minutes or so, but then it goes away when I start the car up again.

BTW, 40 psi is too high for your 20's. You probably feel every tiny rock on the road. You should be around 34 PSI COLD.