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otorvund 05-11-2019 05:23 PM

tire pressure question
 
I have now installed TPMS TireMinder on my trailer tires. I have always set my tires to 80 psi before leaving on trips which is according to the manual. Now we see that the pressure goes up to 94 sometimes when we drive - especially in hot weather.
Is that OK - or should I bleed the tires a bit to get closer to 80?

On the tires it states that Max PSI = 80.
Tire type is Goodyear Endurance ST

daleyocum 05-11-2019 05:50 PM

Quote:

Originally Posted by otorvund (Post 2240511)
I have now installed TPMS TireMinder on my trailer tires. I have always set my tires to 80 psi before leaving on trips which is according to the manual. Now we see that the pressure goes up to 94 sometimes when we drive - especially in hot weather.
Is that OK - or should I bleed the tires a bit to get closer to 80?

On the tires it states that Max PSI = 80.
Tire type is Goodyear Endurance ST

There are lots of people on this forum that swear by inflating those tires to 70-75 pounds cold both to deal with the pressure increase on hot days and to reduce the stress on rivets from an overly firm ride. I used to inflate mine to 80 as you do but have backed off to 75 of late.

StuartsDad 05-12-2019 12:00 AM

Based on this site research, I run 55 psi cold in my GYE's (59-62 hot) and so much better ride. Even at 55, I am still slightly above the recommended psi according to the GYE chart. I ran at 80 psi when we first got our AS because the dealer made it sound like it was an absolute must, but it was like having solid rubber or foam filled tires. Maybe the must be at MAX psi mindset came from the Goodyear Marathon era, I don't know.

CapriRacer 05-12-2019 07:44 AM

Quote:

Originally Posted by otorvund (Post 2240511)
I have now installed TPMS TireMinder on my trailer tires. I have always set my tires to 80 psi before leaving on trips which is according to the manual. Now we see that the pressure goes up to 94 sometimes when we drive - especially in hot weather.
Is that OK - or should I bleed the tires a bit to get closer to 80?

On the tires it states that Max PSI = 80.
Tire type is Goodyear Endurance ST

No, do NOT EVER bleed down a hot tire. Wait until it has cooled before you approach it. (takes an hour and a half.)

Second, tires are designed for pressure buildup. Their burst pressure is several times the max pressure. The max pressures listed are for COLD tires (that is, tires that haven't been operated for a couple of hours.) Hot tires will have higher operating pressures - and that's by design.

Further, you may be experiencing normal pressure buildup. Allow me to explain.

Yes, the rule of thumb says that you shouldn't get more than a 10% pressure buildup - discounting the ambient temperature affects. If you do, you need to plan to fix that by getting more load carrying capacity or slowing down.

If you experience more than 15%, you need to fix this immediately - first step being slowing down, followed by more load carrying capacity as soon as possible (within a day).

Ambient temperature affects? Tire pressure will increase 3% for every 10°F rise in ambient temperature.

So while you are reporting a 17 1/2 % pressure buildup, most of that could be due to the increase in outside air temperature.

KK4YZ 05-12-2019 12:29 PM

Quote:

Originally Posted by CapriRacer (Post 2240631)
No, do NOT EVER bleed down a hot tire. Wait until it has cooled before you approach it. (takes an hour and a half.)

Second, tires are designed for pressure buildup. Their burst pressure is several times the max pressure. The max pressures listed are for COLD tires (that is, tires that haven't been operated for a couple of hours.) Hot tires will have higher operating pressures - and that's by design.

Further, you may be experiencing normal pressure buildup. Allow me to explain.

Yes, the rule of thumb says that you shouldn't get more than a 10% pressure buildup - discounting the ambient temperature affects. If you do, you need to plan to fix that by getting more load carrying capacity or slowing down.

If you experience more than 15%, you need to fix this immediately - first step being slowing down, followed by more load carrying capacity as soon as possible (within a day).

Ambient temperature affects? Tire pressure will increase 3% for every 10°F rise in ambient temperature.

So while you are reporting a 17 1/2 % pressure buildup, most of that could be due to the increase in outside air temperature.

There’s also going to be quite a difference between the tires that are getting direct sunlight and the ones on the other side. After all, the tires are black.

otorvund 05-13-2019 08:55 AM

Good info from everybody. Thank you all :)


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