Sudden drop in tire pressure
 

I did a quick search on tire pressure and saw that most people experienced tire pressure problems in cold weather or a dramatic change in the weather.

I live in SoCal and for the past few weeks, it's been in the high 90s. This past week it's been relatively cool, about the low 80s. So I drove my Fit today, parked it in a friend's neighborhood and went out with them for about 8 hours.

When I came back, I started up the car to head home and noticed the low tire pressure dummy light was on (the one with the flat tire and exclamation mark in it). So I drove to the nearest gas station and checked the pressure. The two front tires were visibly very low on pressure. The pump gauge had the two front tires at 25 psi. I filled them up to about 40 each and it still doesn't looks as perfectly round as the two back tires.

I've had my '09 Fit Sport for about 3 and half months and have about 2800 miles on it. What could have caused this sudden drop in pressure? On earlier drive to my friend's neighborhood, the low pressure light was not on.

Someone didn't play with your tires?

All that weight on the front tires. It will never be as round as the rear.

I wouldn't worry about it, unless it happens again.

Last spring, when overnight temps dipped into the 30's, but daytime temps might flirt with 80, I observed as much as a 5 PSI spread in tire pressure between measurements taken in the morning and again in the evening. My TPS sensor never came on, but then I check my tires weekly and maintain them at 36 PSI min.

All tires lose some air over time. When did you last check them? IMO, once a month isn't often enough to check your tire pressure.

Set your psi in the early morning or in your garage away from sunlight. You guys in socal get strong rays so that alone will throw off your readings... Sometimes by over 5psi.

Set psi by the gauge, not the roundness of the sidewall.

3months is a long time without checking your psi. You should check atleast once a month. Don't just reply on the TPMS. That only triggers when psi is "dangerously" low like under 28psi. I run my tires at 34-38 range depending on what I want.

Thanks for the advice. I have been neglecting to check my tire pressure. Unfortunately I only check it when the light goes off with past cars. I won't make that same mistake again.

also check your tire pressure if you notice a sudden decrease in fuel economy that can't otherwise be explained by changes in driving habit / conditions.

You definitely don't want to wait till the light comes on...your gas mileage will suffer along with handling/safety. I'm not as diligent as I could be so I'm not preaching ;)

I top off around 40ish...park it in the garage and adjust in the morning to 36 before leaving for work. Finding an air station around here that works is the actual challenge.

Like others have stated, the fronts are never going to look like the rears. Visual approximation is something you can throw out the wondow...get a decent gauge.

Why not get a tire pump? Then you don't have to hunt for one at a gas station. Even the little $10 pump that plugs into the cigarette lighter will get the job done...albeit slowly...

This summer in Seattle the temps have gone from 70s to 90s-100s to 60s overnight in the past 3 weeks. Each time the tire pressure seriously dropped.

Yep great idea. I always have one aboard my ride. Cuts my dependence on going to the gas station for tire inflation, and also allows me to more accurately measure and inflate the tires because you don't have to drive off to do it (and introduce heat into the tires and screw up the reading in the process)