satur9poet

Morning, all!

Late last night my TPMS light came on out of the blue. When i reached my destination i inspected the tires and saw nothing unusual...car has stock rims and factory tires. Upon driving it home, the light went off, then came on again about a minute later and stayed on until I got home.

Just how sensitive is TPMS? Will it alert the driver to even a slight drop in tire pressure? Of course there's always the possibility that I ran over a nail or other sharp object and there's a slow leak coming from somewhere. I'm going to add some air to the tires today to see if that will help.

Advice is appreciated!

Nuke

Most TPMS sensors will provide annunciation at roughly 26 PSI but there are accuracies and defects that can always come into play. Looking at a tire cannot accurately identify a tire that is about 2-4 PSI lower than it should be. Everyone should have a tire pressure gauge. Get one and use it regularly. Tire pressure will change about 1 PSI for every 10 degree F change in ambient temperature.

SpartaPerformance

Looking at the tire?? You're kidding right? Tires can lose up to 5psi every month on there own. Like stated in the above post EVERYONE needs to have a tire pressure gauge and they should be checked atleast once a month. This is the reason why TPMS exists because people don't know how to maintain their tires and they would blame manufacturers for blow outs.

satur9poet

I stand corrected. Durr! I was under the impression that it only went off if you were dangerously close to a flat/blowout.

JIM5.0

No, fortunately it does not go off that late.

Unfortunately, the TPMS is more sensitive to temperature changes if you use regular breathable air. Air can cause the the to expand or contract such that the TPMS throws a light.

I hear guys at the tire shops always preaching about using as pure of nitrogen as possible because nitrogen is less prone to expanding and contracting with temp changes.

If your tires are filled with everyday joe-blow 50cent-$75cent gas station pump air, you could be throwing low tire pressure lights like crazy during the winter, at least until you drive for a few minutes on your tires to warm them up and the warmed-up tire heats the air inside to expand back to the proper pressure.

Nuke

Cut me a break. Anyone that gives a damn about their car compensates for tire pressure changes as the seasons progress. If you want to invest in N2 its your lazy-azz, hard earned money. If you need to add or remove 3-5 PSI of air from your tires every 2-3 months, a simple bicycle hand pump is all you need. That's about 8 pumps on the average hand pump per pound of air. And if that's too much for you, let me help you across the street.

siggyfreud

The TPMS doesn't alert me at 40PSI but will at 41 PSI on my Caddy. Likewise, the Mustang has a threshold that once you cross it, it will go off. Temperature changes or spirited driving can raise/lower your tire pressure by over 10 PSI which is why it was bouncing on and off for you.

JIM5.0

No, that is not what I meant. Besides, you only quoted my last paragraph. I meant the info for both my last and 2nd paragraph to be together as one unit.

The point I was trying to get across is that tire store guys preach nitrogen.
I did not mean it as "I" preach nitrogen.

Yes, it is beating a dead horse (But I would hope that the horse is not dead in your cute little icon, that is just too sad. I'd like to think the horse were sleeping instead! LOL)
Just like said in several threads above, people are not responsible enough to check their tires at least once a month. The result is the USDOT stepping in, most likely at the request of the tire and automotive industry, so that TPMS must be included in all new cars now sold in the US.

In line with your dead horse, I agree that it is stupid that general American laziness has caused such a regulation from Big Brother to fall upon us all.