[stancy]

I am getting ready to take a trip to Phoenix (HOT). I keep 42 PSI in my tires locally (East Texas). I am concerned that the pressure may increase to unsafe levels while traveling in the desert. It anyone has any input on this, please respond. I'm thinking I should reduce the cold PSI to around 36 to 38 before my trip. Thanks for any help.

Stan

 

[kirby]

Pressure goes up about 1psi for each 10 degrees. Why not just take a tire gauge with you?

 

[ChasSuitt]

Howdy, fellow Texan...

Postings on another Prius forum indicates that LOWER tire pressure in hot weather makes the sidewalls flex more, creating more heat and adds to the problem rather than relieves it. Your 42/40 psi is within the posted maximums on the stock Prius tires. My opinion: Leave your tire pressures as they are.

We're "enjoying" ~100º temps in Dallas w or 3 days a week. I run my original tires at 40/38.

 

[Phoenix]

Tire Pressure in Phoenix

I have been running 44/42 on Michelin HydroEdge tires for the last 35,000 miles. Your 42/40 should be fine here, but I wouldn't let any air out.

Ford SUVs and Firestone got some bad publicity here in Arizona the last couple of years due to tire failures, but it was mostly caused by low tire pressure in the summer. Dealers were recommending lower pressures to make trucks ride like cars. The heat destroyed the tires.

Higher pressures help tires run cooler; less flexing, like ChasSuitt says.

Check your tires first thing in the morning, before you start driving on them, and fill them if necessary. If you pump them up in Phoenix, you may be able to deflate them slightly when you get home.

By the way, our highs have cooled a few degrees to under 110 the past week or so, but the monsoons are here and our relative humidity has gone from 5-10 percent in June to 40 percent and higher. 105 and 65% feels worse than 112 and 10%. Bring a hat and some cold drinks, and try to stay indoors or at least in the shade!