Tire pressures

[huy397]

It's getting colder now ( about -5C to -15C ) and my tires are a little over inflated and I want to deflate it a little bit for winter.What reading should I have for optimal condition ? I am still rolling around in stock 16" Goodyears.What do "Cold" or "Warm" mean with respect to tire pressures ( as outline in the glove-box sticker ).Is it cold/warm air in the tire ? or cold/warm in term of outside temp?thank you

[MadBill]

The recommended "cold" pressures are before you start driving, with the tires and the air inside them at ambient temperature. Since the tires increase their temperature and pressure due to flexing (under some conditions the pressure could rise 5 psi or more), if you were to adjust the base Vibe, for example, to 32 psi after a number of miles driving, they would now be "hot" and would be underinflated at that temperature. Also, as the weather cools, the tire pressure drops, so in the Fall it's especially important to check and top them up regularily. For example, if you kept your car in a heated garage and set the tires to 32 psi at 70 F., then drove out into a forty below winter and parked it over night, they would likely drop to ~ 25 psi. This would be major underinflation, since minus forty would be the ambient operating temperature.BTW, tires should never be set lower for the Winter! The only time tires should be (temporarily) "aired-down" is to improve traction in deep sand.BTW2, there is a maximum pressure printed on the sidewall which is the safe maximum for the tire regardless of what vehicle it is on. It has nothing to do with the correct pressure for your vehicle.Hope this helps!

[huy397]

Quote, originally posted by MadBill »The recommended "cold" pressures are before you start driving, with the tires and the air inside them at ambient temperature. Since the tires increase their temperature and pressure due to flexing (under some conditions the pressure could rise 5 psi or more), if you were to adjust the base Vibe, for example, to 32 psi after a number of miles driving, they would now be "hot" and would be underinflated at that temperature. Also, as the weather cools, the tire pressure drops, so in the Fall it's especially important to check and top them up regularily. For example, if you kept your car in a heated garage and set the tires to 32 psi at 70 F., then drove out into a forty below winter and parked it over night, they would likely drop to ~ 25 psi. This would be major underinflation, since minus forty would be the ambient operating temperature.BTW, tires should never be set lower for the Winter! The only time tires should be (temporarily) "aired-down" is to improve traction in deep sand.BTW2, there is a maximum pressure printed on the sidewall which is the safe maximum for the tire regardless of what vehicle it is on. It has nothing to do with the correct pressure for your vehicle.Hope this helps!thanks for the reply.My tires are over-inflated to begin with ( that I am sure of ), that's why I want to deflate it a little now... although I should've done that shortly after taking delivery. I will take a reading tomorrow after work and get a "warm" tire reading.Question: how long does it usually take for a tire to be "warm" ? What are the optimal pressure for Vibes ?thank you

[MadBill]

Quote, originally posted by huy397 »thanks for the reply.My tires are over-inflated to begin with ( that I am sure of ), that's why I want to deflate it a little now... although I should've done that shortly after taking delivery. I will take a reading tomorrow after work and get a "warm" tire reading.Question: how long does it usually take for a tire to be "warm" ? What are the optimal pressure for Vibes ?thank youThe factory overinflates the tires for shipping, but the dealer is supposed to set them to spec. during the pre-delivery inspection. They often forget.Depending on driving conditions, it could take up to an hour of driving for the tire temperature/pressure to stabilize. Recall however, that the specified pressure is when cold, i.e., not driven more than a mile or so for the previous several hours. The specified pressure is found on a label in the glove box. For the base Vibe, it is 32 psi cold. Some people go higher, which, within limits, can help cornering response at the cost of a rougher ride, but if operated regularily at more than a few pounds above spec. can result in uneven (center) wear.