Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×


Reply
 
Thread Tools Display Modes
Old 12-22-2016, 07:29 PM   #21
Senior Member
 
Join Date: Jan 2015
Location: Englewood FL
Posts: 2,797
Actually the problem really occurs when going north in the winter. 75 degrees to 25 degrees will lose you about 10% in cold pressure. gaining 10% is not a real problem, but losing it will put you below the minimum cold pressures on most tires. I don't worry about doing it in the morning when they are cold, I just know that I need to add air on the way north in the winter.
__________________

2015 335DS
ScottBrownstein is offline   Reply With Quote
Old 12-22-2016, 07:49 PM   #22
Senior Member
 
Join Date: May 2014
Location: IL
Posts: 1,295
Hi,

Which raises the interesting technical question -- how much over the stated cold pressure on the sidewall is OK?

My cold pressure is 80 psi. My TPMS goes off when it reaches 89 psi on a very hot day on dark asphalt surfaces. I have always believed this is a ten percent threshold being exceeded that is built into the monitor itself.

When that happens, I eventually kill the alarm sound, and start watching carefully for greater increases, but it has never gone over 90 psi. I also watch the temperature readings to be sure something else is not developing.

Anyone have any thoughts on this?

Rich Phillips
__________________
Rich Phillips
2019 K-2500 Duramax Crew Cab
2014 Silverback 33RL
richp is offline   Reply With Quote
Old 12-22-2016, 07:54 PM   #23
Senior Member
 
Join Date: Jan 2015
Location: Englewood FL
Posts: 2,797
There is a max pressure on the sidewall. My cold pressure is 90# and the sidewall pressure is 110. When running I can easily go to at least to 105 or more. The max pressure is the max cold pressure, not the maximum running pressure as most people do not have TPMS units that give the pressure in real time.

the reason there is a minimum cold pressure is to prevent too much flexing in the sidewall.
__________________

2015 335DS
ScottBrownstein is offline   Reply With Quote
Old 12-22-2016, 08:02 PM   #24
Senior Member
 
Join Date: May 2014
Location: IL
Posts: 1,295
Hi Scott,

So it's your view that 110 might be a level I need to avoid while actually running down the road?

Gotta take a look before I leave, to see if mine has a second number like that on the sidewall.

Thanks.

Rich
__________________
Rich Phillips
2019 K-2500 Duramax Crew Cab
2014 Silverback 33RL
richp is offline   Reply With Quote
Old 12-22-2016, 08:20 PM   #25
Senior Member
 
Join Date: Jan 2015
Location: Englewood FL
Posts: 2,797
No, if your sidewall says 110 max that means you should never have a cold pressure above 110. The actual recommended cold pressure is on your placard and is based on the vehicle weight from the manufacturer. On my RV it is 90 PSI "cold", but the tires can handle a cold pressure up to 110 PSI, but presumably that would be for more vehicle weight than I have. If you have too much cold pressure, you will wear the center of the tire as it will not sit flat on the road. Now, with 90 PSI cold, I have seen 105 or more when running down the road...i.e. "hot" pressure.
__________________

2015 335DS
ScottBrownstein is offline   Reply With Quote
Old 12-22-2016, 08:36 PM   #26
Senior Member
 
Join Date: May 2014
Location: IL
Posts: 1,295
Hi Scott,

I know my sidewall cold number is 80.

What I was trying to ascertain was if there is some known or authoritatively estimated higher number which -- if it appears on my TPMS monitor while going down the road, would make it wise to start thinking about stopping and bleeding off some pressure.

Obviously, each morning, as I move from one temperature gradient to another, I can check and adjust the cold pressure. But I have more than once fretted about whether the increased daytime running pressures might be trending toward problematic.

Thanks for your thoughts.

Rich
__________________
Rich Phillips
2019 K-2500 Duramax Crew Cab
2014 Silverback 33RL
richp is offline   Reply With Quote
Old 12-22-2016, 08:47 PM   #27
Senior Member
 
Join Date: Jan 2015
Location: Englewood FL
Posts: 2,797
If you think about it, the answer has to be NO! As long as you are inflated to the recommended cold pressure and below the maximum load rating of the tire in question, you should be able to let the pressure rise to any temperature that it wants to. Otherwise, the tire would be incapable of running under the specified load at normal ambient temperatures.
__________________

2015 335DS
ScottBrownstein is offline   Reply With Quote
Old 12-22-2016, 08:54 PM   #28
Senior Member
 
Join Date: May 2014
Location: IL
Posts: 1,295
Hi Scott,

You're right on target.

My nagging thoughts about this mostly come when remembering days when ambient air temp was high, the sun was direct and very hot, and beating down on dark pavement you could cook an egg on. Some Western desert summer days start very cool and wind up blistering. And those are the trips I have had those concerns.

But I'm probably over-obsessing. And it certainly shouldn't be a problem next week on the way west.

Have a good one.

Rich
__________________
Rich Phillips
2019 K-2500 Duramax Crew Cab
2014 Silverback 33RL
richp is offline   Reply With Quote
Old 12-23-2016, 06:16 PM   #29
Senior Member
 
Join Date: Jul 2009
Location: Warsaw,NC
Posts: 7,184
I run at max whatever it says on the place card and the temperature is checked in the morning when the tires are cold. On my Cedar Creek the tires are rated at 110 lbs and that's what I run, the camper has a yellow place card and that's where it says the tire pressure is. My TPMS is set at 128. My tow vehicle tires are 60 lbs front and 80lbs rear. I always check the air in the morning when the tires are cold, I never check them when the tires are hot, my TPMS checks them all the time. I normally only drive 300 to 400 miles a day and sometimes less.


Sent from my iPhone using Forest River Forums
spock123 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Featured Campgrounds

Reviews provided by

Disclaimer:

This website is not affiliated with or endorsed by Forest River, Inc. or any of its affiliates. This is an independent, unofficial site.



All times are GMT -5. The time now is 12:24 PM.