this afternoon we had a hail for a while it was crazy, i was at my friend's house when i saw the hail i drove my car to the underground parking, after driving for 2 mins my tire pressure sensor went off, so i checked my tires i'm pretty sured i had all four tires pumped at 35psi just few weeks ago, and now all 4 tires are at 30psi. why would a hail makes all 4 tires drop 5 psi ?
i pumped my tires back to 35psi and warning sign dissapeared. should i check my tires ?

 

My guess is that the hail storm dropped the out side temp low enough to cause the pressure to drop. Did your outside temp drop from say 90's to the 70's during the hail storm?

 

Yes we did get a temp drop (about 10-15 degrees) which would account for some of your pressure loss. I doubt 5 pounds tho.

It's more likely that you pumped the tires on a very hot day, resulting in lower pressures on a cooler day.

I doubt you've got an probs with them since they all appear to be an even pressure. Just check them more often and adjust as needed for temp change.
C.

 

thanks !! flood everywhere in toronto this afternoon ! i hope no one has any problem with their car

 

I had this happen to me Friday morning at 5AM as I was driving home and about 5 minutes into the drive I heard a long beep. I had driven from Fresno to the Central coast Thursday evening. It is much cooler at the coast and it been 100+ hear for almost a month. Tires looked fine and my gage reported 34 psi so I continue on my way home (2 hour drive) After purchasing a better tire pressure gage I found old one was off a bit added some air and light turned off. I was glad to see that the sensor works.

 

lol, this is simple physics guys, when air is cooled the molecules pull closer together causing a pressure drop. My guess is your tires were closer to 33 PSI as you may have filled them last on a warm day or something, then the temperature drop caused the pressure to go down. If all 4 tired went down equally then that's the only cause, unless of course someone dropped nails all over the road

 

A friend of mine worked for an Air Conditioning firm. He was lazy and would fill his tires with Freon. First cold spell came along, and when he went outside to go to work, all of his tires were flat! Freon turns to a liquid at about 72 degrees.

 

I had the same thing happen to me two weeks ago. The day time high was 86 and it dropped to 59 that night. I got in my car and drove 4 blocks and heard the long beep and saw the low tire pressure warning light and pulled over to discover all 4 tires had lost 5psi. I had just checked the tire pressure earlier that week, but losing 5pounds in one day seems a bit odd.

 

~1psi difference per 10F change in temp.

check your tire pressure once a week, minimum once every 2 weeks and more
frequently when temps fluctuate during spring and fall.