How sensitive is the low tire pressure system?

[Jon Jackson]

Got into my car this morning and it said I have low tire pressure in the back rear driver side tire....seems fine to be...turned engine off and on a few times still says low pressure.

Are they very very sensitive that maybe it's just slightly down and I can't tell? Seems hard as a rock but I dunno...

 

[radicaltimes]

When the pressure drops to I think 25 or 28psi it will cause the light to come on.

 

[Buford T Justice]

Correct. It only goes off if the pressure drops below a certain number.
Put air in the tire and it will go away.

Touch and sight aren't good tools for judging tire pressure, use a pressure gauge (around $3 at most stores) and you'll see the pressure is probably sitting around 30psi.

Daily temperature changes/driving will be enough to raise/lower the pressure over the sensors threshold.

 

[Mark_888]

Got into my car this morning and it said I have low tire pressure in the back rear driver side tire....seems fine to be...turned engine off and on a few times still says low pressure.

Are they very very sensitive that maybe it's just slightly down and I can't tell? Seems hard as a rock but I dunno...

Seems hard as a rock? Get yourself a decent digital tire pressure gauge for abut $10-15. It will save you a lot of money over the long term. Improperly inflated tires are the number one cause of excessive tread wear, and since tires are about $200 each, an accurate tire gauge is an excellent investment.

 

[GRIFF]

Got into my car this morning and it said I have low tire pressure in the back rear driver side tire....seems fine to be...turned engine off and on a few times still says low pressure.

For about $125.00 you can go to the local welding supply store and purchase a regulator and put a deposit on a tank of nitrogen.

Doesn't vary tire pressure with heat and improves tire life and consistency of ride. I have been using nitrogen in all my vehicles, including motorcycle, for years. The nitrogen molules are larger in diameter than air so it also prolongs the need to add pressure.

Griff

 

[Mark_888]

For about $125.00 you can go to the local welding supply store and purchase a regulator and put a deposit on a tank of nitrogen.

A Costco membership will let use their nitrogen for free, and they do free 7500 mile rotations (not sure if you have to purchase tires there).

Doesn't vary tire pressure with heat and improves tire life and consistency of ride. I have been using nitrogen in all my vehicles, including motorcycle, for years. The nitrogen molules are larger in diameter than air so it also prolongs the need to add pressure.

All gases expand with heat. All of them. It is called Charles Law.

However, you are correct that tires filled with 95%+ nitrogen leak less than those filled with air (slow and normal leaking that occurs in all tires).