Tire pressure

[Mikey999]

I have  18 inch factory Michelin energy saver tires.  The recommended kpi is 241 which is 35 psi.  Todays  heat when i was driving  they were as high as 284 kpi. which is just over 40 psi. I was on highway.  Is this safe or should i let some pressure out?

[stevejones]

Safe

[Grumpy Bear]

What is the maximum inflation pressure stamped in the tires sidewall? 

[amxguy1970]

With heat and driving tires increase in pressure. Set them when cold and in the shade around 35 and it will heat up around 5 degrees give or take when driving, being in the sun and when the temp outside climbs. No worries, they can usually handle a whole lot more. Those tires appear to have a max inflation pressure of 44 psi (which is the max when cold). You are completely safe and have them set at the correct pressure. 

 

Tyler

[Grumpy Bear]

It was 65 F here yesterday at 6 AM and by midday 90 F. If I set my pressure in the morning in the shade at 35 psi it will be 37.5 psi at 1 pm before I leave the driveway providing it's still in the shade. Driving at the speed limit on the Interstate will raise it about 2.5-3.5 psi more. (All Season tires). 40.5 psi so the TPMS could read 40 or 41. The sunny side at mid day might even be a degree higher. If the side wall number is 44....

 

No problem safety wise. However......

 

Here's the load chart from my Bridgestone Dueler 684 II HT. Sidewall pressure max is 41 psi but load max is at 35 psi COLD. 

 

 

That number on your sidewall is maximum pressure period. Even during mounting. That cushion above the maximum load value is to accommodate the pressure rise above the cold set pressure for heat of work and some ambient latitude. 

[flyingfool]

i run mine at 31, in summer heat they pump up to 35 psi after 30 minutes.. energy savers are designed to be run 40 psi for low resistance drag, after awhile they will pump up to 45 psi after a long trip

Edited July 4, 2020 by flyingfool