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

Go Back   Keystone RV Forums > Keystone Tech Forums > Tires, Tires, Tires!
Click Here to Login

Reply
 
Thread Tools Display Modes
 
Old 03-15-2020, 03:56 PM   #1
Hey Louie
Senior Member
 
Join Date: Mar 2018
Location: Eastern Shore of Maryland
Posts: 113
Tire pressures, what to expect

Just took out first trip since installing a TPMS. When we pulled out of the driveway the readings were from 108 to 110. As I traveled down the road Max speed 60 mph overcast day with the temps in the mid 50's the pressures elevated to 122 to 125 psi. Is this the norm? At what level is there reason for concern? Would the pressure get even higher on warmer days? Nice to know the readings but it be even nicer if I new what to expect.
Thanks.
__________________
Dennis and Lisa
2019 Alpine 3700fl
2016 Chevy Silverado 3500 DRW Duramax
Hey Louie is offline   Reply With Quote
Old 03-15-2020, 04:36 PM   #2
Canonman
Senior Member
 
Canonman's Avatar
 
Join Date: May 2016
Location: South Jordan, Utah
Posts: 2,221
I found the same issue with our Carlisle tires. I changed tires and added the TPMS at the same time. Never knew the temps and pressure went up like that while driving.
After checking with the dealer as well as a relative in the tire business, the answer was "this is normal". Both recommended keeping an eye on the pressure and temps primarily looking for any inconsistencies among the tires being monitored. They assured me that the tire manufacturers allow for the increase in pressure and heat in their engineering. I can even notice which side the sun is shining on by several degrees
I once noticed one trailer tire about 15 degrees hotter than the others. Turned out the brake on that wheel had seized slightly creating the added heat. Having the TPMS saved our vacation that summer!
Attached Thumbnails
Click image for larger version

Name:	_MG_4788.jpg
Views:	188
Size:	241.5 KB
ID:	25588  
__________________
2017 Cougar 279RKSWE
2007.5 Dodge Ram 2500 6.7 Cummins
Retirement Training Completed
I think the little voices in my head have started a chat group.
Canonman is offline   Reply With Quote
Old 03-15-2020, 04:40 PM   #3
NH_Bulldog
Senior Member
 
NH_Bulldog's Avatar
 
Join Date: Apr 2019
Location: Henniker
Posts: 2,016
If tires are set properly to cold pressure rating (technically at 68° F with 1 psi added or subtracted for each 10° above or below). That’s the overly anal method, but in the real word check and set when “cold” meaning not driven on in past 3 hours. Either way rise in temperature in use should still keep you within design limits of the tires.

Now that being said, your actual tires will decide how safe this is. Stock tires (like Trailer King, or Power King) might pose a concern as they have a dubious reputation, whereas aftermarket tires (like Goodyear, Carlisle or Sailun) might give you more peace of mind.
__________________
Rob & Amy
2019 Passport 240BH SL (current)
2024 Cougar 29BHL (on order, due early May)
2022 Ford F250 7.3L Godzilla Crew Cab 4x4
NH_Bulldog is offline   Reply With Quote
Old 03-15-2020, 04:53 PM   #4
66joej
Senior Member
 
66joej's Avatar
 
Join Date: Feb 2014
Location: radium hot springs bc
Posts: 2,007
I believe the manual says set tire pressures when cold. Could be 0F or +70F. YMMV
__________________

2018 Ram 3500 6.4 Harvest Edition
2018 Cougar 27RESWE
66joej is offline   Reply With Quote
Old 03-25-2020, 04:26 AM   #5
RVPP
Junior Member
 
Join Date: Oct 2019
Location: Whiting
Posts: 20
air pressure

Quote:
Originally Posted by 66joej View Post
I believe the manual says set tire pressures when cold. Could be 0F or +70F. YMMV

Back in high school science class I recall "STP". Standard temperature and pressure. Standard temp. was 70degs. F. at sea level. How if you're in Denver the air pressure in WAY different than say Miami not to mention the temp. So all of you nice folks can figure out what 'cold' is. Me, I stay near sea level and I prefer warm temps. Happy trails folks.
RVPP is offline   Reply With Quote
Old 03-28-2020, 12:16 PM   #6
CWtheMan
Senior Member
 
CWtheMan's Avatar
 
Join Date: Feb 2010
Location: Taylors, SC
Posts: 3,031
This is how NHTSA describes proper tire inflation pressures for OE tires.

"The vehicle manufacturer's recommended tire inflation pressure is the proper psi when a tire is cold, meaning it has not been driven on for at least three hours. To get an accurate tire pressure reading, you must measure tire pressure when the tires are cold."

When someone reads more into what's there, it's their opinion.
CWtheMan is offline   Reply With Quote
Old 03-29-2020, 04:08 AM   #7
chunker
Senior Member
 
chunker's Avatar
 
Join Date: Jan 2020
Location: Hartford AL
Posts: 439
It's amazing to read all these posts where some start talking about "their method" referring to weights of the RV, PSI for tires etc. Since I suspect 90+% of RV owners can't spell CAT scales, know where to find them, or how to use them. I suspect some people don't trust or use a TPMS because #1 they don't understand it, #2 they are too cheap to buy one, #3 they operate in a "what I don't know can't hurt me" mode. Then there's of course the trolls who just make up crap and post on forums to stir the pot.

For the most part you are free to operate as recklessly as you wish just don't take out other innocent people in the process. I won't cite examples because some wouldn't understand anyway. Me, I'll continue to utilize my TPMS, know my weights based on scale tickets, adjust speed and load for the conditions, and try use the best available equipment. If I stepped on someones toes here I'm really sorry you stuck your toes out so far.
__________________
2021 Omni SX32
2012 Crusader 355BHQ (girl friends)
2020 Ram 1500 Laramie 4WD, toad
2019 Harley Davidson Heritage Classic 114 (the toy)
chunker is offline   Reply With Quote
Old 03-22-2020, 08:28 AM   #8
Tireman9
Senior Member
 
Join Date: Sep 2018
Location: Akron
Posts: 453
Quote:
Originally Posted by NH_Bulldog View Post
If tires are set properly to cold pressure rating (technically at 68° F with 1 psi added or subtracted for each 10° above or below). That’s the overly anal method, but in the real word check and set when “cold” meaning not driven on in past 3 hours. Either way rise in temperature in use should still keep you within design limits of the tires.

Now that being said, your actual tires will decide how safe this is. Stock tires (like Trailer King, or Power King) might pose a concern as they have a dubious reputation, whereas aftermarket tires (like Goodyear, Carlisle or Sailun) might give you more peace of mind.

Sorry but setting tire pressure is done at Ambient Temperature. No adjustment or calculation to some theoretical High School Chem lab experiment.
No idea what you think the "design limits" are for tires. The MINIMUM pressure at ambient temperature is the pressure in the charts for your Actual measured load on the heavy end of each axle.
I recommend adding 10% so you are not chasing your tail whenever the air temperature changes a few degrees.


I would expect "normal" operating temperature to increase above ambient by 10F to 50F depending on ambient as cooler air will transfer heat faster to the wheel and then to the air. With a +50F that would suggest a pressure increase of 10% to 20% as "normal" variation comes from air flow and heat transfer variations. You also have variation of +/- a couple % for pressure reading from TPMS.


Please stop overthinking this. I have covered this is detail ini my blog.
__________________
Retired Tire Design Engineer (40 years). Serve on FMCA Tech Advisory Committee. Write a blog RV Tire Safety. Read THIS post on Why Tires Fail.
Tireman9 is offline   Reply With Quote
Old 03-22-2020, 12:11 PM   #9
jadatis
Senior Member
 
Join Date: May 2013
Location: Holland ( Europe)
Posts: 178
I have been calculating again.
Your TMPS measured 108psi/110psi at 50 degrF ambiënt temp, so not driven this means inside tire also 50 degrF. If then you would have read it when ambiënt temp was 65 degrF the second written would be given by TMPS system, probably rounded to 1 psi, most TMPS give it in steps of 1 psi. And 3th is the presure you read when driving so warmer inside tire air.
The about 10% pressure-rising when ambiënt temp is 65 degrF and driving about 50/55mph, comes from an inside tire temp of 110 to115 degr F in tire.


108 psi /50 degrF, 111.6 psi/ 65 degrF, 122psi/109 degrF.

110psi/50 degrF , 113.7 psi/ 65 degrF , 125psi/112 degrF.

Draw your own conclusions, this all I gave on a " nice to know basis"
Realise that I call myself " pigheaded Dutch selfdeclared tirepressure-specialist" , this to point out that I am not a profesional in tires.
For most Dutch and not American, is already a reason to not trust my given information. But the calculation is right asuming no vollume change of tire by the different pressure, wich it practically is for an already pressurised tire.
jadatis is offline   Reply With Quote
Old 03-22-2020, 01:25 PM   #10
notanlines
Senior Member
 
notanlines's Avatar
 
Join Date: Oct 2014
Location: Germantown, TN
Posts: 6,308
Let me throw this wrench into the works. Your TPMS probably does a reasonable job of tire pressures. Sometime take your handy-dandy infrared thermometer and measure the temperature of the wheel and the surface of the tire and see what you get.
It has been said a few times, now once more. Don't overthink this. Air pressure before you leave in the morning and be done with it.
__________________
Jim in Memphis, Wife of 51 years is Brenda
2019 F450 6.7 Powerstroke
2018 Mobile Suites 40RSSA
2021 40' Jayco Eagle
2001 Road king w/matching Harley sidecar
2021 Yamaha X2 Wolverine 1000
notanlines is offline   Reply With Quote
Old 03-22-2020, 01:48 PM   #11
JRTJH
Site Team
 
JRTJH's Avatar
 
Join Date: Mar 2011
Location: Gaylord
Posts: 26,846
When you consider that the temperature sensor in any TPMS "stem system" is going to measure the temperature "at the end of a stalk, 1.5-2.5 inches out in the airstream" and that "stalk" may or may not transfer heat as efficiently as the wheel, rubber tire, air inside that rubber tire might transfer heat, then add in the "cooling effect" of that "temperature sensor" slinging around in the atomosphere, sometimes aided by cooling humidity, sometimes hampered by "scorching sunlight at high noon" and you'll begin to get the idea that temperature "measured by a TPMS valve stem cap" is, at the very best, a close approximation of reality.... Then when you add in all the variables encountered, you can easily come to the conclusion that it may very well not even be a "close approximation"....

TPMS "external sensors" don't do a very good job of "sensing internal tire temperatures".... About the only "close to reality" is to compare both the sensors on the shady side of the trailer and compare both the sensors on the sunny side of the trailer. If each "pair is somewhat close" then that's about as "much temperature reality as you'll get" from a "stem cap TPMS" readout.

Think of it this way: Aim the red dot from an infra-red thermometer at a mirror, bounce the reflection off the mirror toward the tire and judge whether you're close or not to reading the area of the tire where you're concerned with temperature.... Your TPMS may (or may not) be as accurate as the reflected red dot reading.....
__________________
John



2015 F250 6.7l 4x4
2014 Cougar X Lite 27RKS
JRTJH is offline   Reply With Quote
Old 03-15-2020, 05:08 PM   #12
slow
Senior Member
 
slow's Avatar
 
Join Date: Jan 2014
Location: Winnipeg, Canada
Posts: 1,196
I set my air pressures 5 psi below max when the ambient temperature first thing in the morning at daylight is 15 C (~60F). That is the typical temp for us in the mornings when we set off towing. I am comfortable with the 5 psi below max since a 10 F temp rise brings them up to max. This way I do not have to keep adjusting the air pressure the entire season.
__________________
2018 Jayco Eagle HT 265BHS (previous: 2015 23RB Passport Elite, ProPride)
2015 F250 XLT SB Crew, 6.2l gas
PullRite 16K SuperGlide w/SuperRail
Reese 5th Airborne (bagged) Pin Box
RoadMaster Shock Kit
X-Factor Cross Bracing
slow is offline   Reply With Quote
Old 03-15-2020, 09:14 PM   #13
CWtheMan
Senior Member
 
CWtheMan's Avatar
 
Join Date: Feb 2010
Location: Taylors, SC
Posts: 3,031
Quote:
Originally Posted by slow View Post
I set my air pressures 5 psi below max when the ambient temperature first thing in the morning at daylight is 15 C (~60F). That is the typical temp for us in the mornings when we set off towing. I am comfortable with the 5 psi below max since a 10 F temp rise brings them up to max. This way I do not have to keep adjusting the air pressure the entire season.
If the max you speak of is the recommendation on the vehicle certification label, you're starting the day off 5 PSI under inflated.
CWtheMan is offline   Reply With Quote
Old 03-22-2020, 08:30 AM   #14
Tireman9
Senior Member
 
Join Date: Sep 2018
Location: Akron
Posts: 453
Quote:
Originally Posted by slow View Post
I set my air pressures 5 psi below max when the ambient temperature first thing in the morning at daylight is 15 C (~60F). That is the typical temp for us in the mornings when we set off towing. I am comfortable with the 5 psi below max since a 10 F temp rise brings them up to max. This way I do not have to keep adjusting the air pressure the entire season.



I do not know why so many people thing under inflating their tires is a good idea. Every mile you run underinflated does some additional damage to your structure.


With my recommended +10% you have plenty of room for daily changes without having to mess with your tires. Just NEVER run lower than the MINIMUM inflation based on scale measured load and the info in the tables.


Tires can tolerate a significant increase in pressure. We tire engineers know that and design and test accordingly.
__________________
Retired Tire Design Engineer (40 years). Serve on FMCA Tech Advisory Committee. Write a blog RV Tire Safety. Read THIS post on Why Tires Fail.
Tireman9 is offline   Reply With Quote
Old 03-22-2020, 10:39 AM   #15
slow
Senior Member
 
slow's Avatar
 
Join Date: Jan 2014
Location: Winnipeg, Canada
Posts: 1,196
Quote:
Originally Posted by Tireman9 View Post
I do not know why so many people thing under inflating their tires is a good idea. Every mile you run underinflated does some additional damage to your structure.


With my recommended +10% you have plenty of room for daily changes without having to mess with your tires. Just NEVER run lower than the MINIMUM inflation based on scale measured load and the info in the tables.


Tires can tolerate a significant increase in pressure. We tire engineers know that and design and test accordingly.

So rather than setting 5 psi below max at 15 C, I should set to max at 15 C since that is my typical morning and departure temp.
__________________
2018 Jayco Eagle HT 265BHS (previous: 2015 23RB Passport Elite, ProPride)
2015 F250 XLT SB Crew, 6.2l gas
PullRite 16K SuperGlide w/SuperRail
Reese 5th Airborne (bagged) Pin Box
RoadMaster Shock Kit
X-Factor Cross Bracing
slow is offline   Reply With Quote
Old 03-15-2020, 05:08 PM   #16
travelin texans
Senior Member
 
travelin texans's Avatar
 
Join Date: Nov 2017
Location: Picacho, Az
Posts: 6,809
"Cold pressure" is before traveling. Best to check in the morning before traveling. You do not have to check precisely at 68 degrees.
__________________
Full-timed 10+ years
Sold '13 Redwood FB
Traded '13 GMC Denali DRW D/A
Replacement undetermined
travelin texans is offline   Reply With Quote
Old 03-22-2020, 08:35 AM   #17
Tireman9
Senior Member
 
Join Date: Sep 2018
Location: Akron
Posts: 453
Quote:
Originally Posted by travelin texans View Post
"Cold pressure" is before traveling. Best to check in the morning before traveling. You do not have to check precisely at 68 degrees.



^x2
__________________
Retired Tire Design Engineer (40 years). Serve on FMCA Tech Advisory Committee. Write a blog RV Tire Safety. Read THIS post on Why Tires Fail.
Tireman9 is offline   Reply With Quote
Old 03-22-2020, 10:26 AM   #18
Jerry S
Member
 
Join Date: Mar 2017
Location: Hillsboro
Posts: 53
Way too many worry warts here, do as Tireman9 says and forgetaboutit.
Jerry S is offline   Reply With Quote
Old 03-15-2020, 06:42 PM   #19
tech740
Senior Member
 
tech740's Avatar
 
Join Date: Jul 2014
Location: Hemlock
Posts: 816
I have always been told that you inflate to max psi before travel and20% increase in pressure is safe.
__________________
R.J. and Ginger

2019 Ram 3500 6.7 HO, Aisin Trans 3:73
Reese Goosebox
2019 Sandpiper 379FLOK
tech740 is offline   Reply With Quote
Old 03-16-2020, 10:05 AM   #20
Hey Louie
Senior Member
 
Join Date: Mar 2018
Location: Eastern Shore of Maryland
Posts: 113
Quote:
Originally Posted by tech740 View Post
I have always been told that you inflate to max psi before travel and20% increase in pressure is safe.
That's what I was looking for, thanks.
__________________
Dennis and Lisa
2019 Alpine 3700fl
2016 Chevy Silverado 3500 DRW Duramax
Hey Louie 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
Forum Jump

» Featured Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3
Disclaimer:

This website is not affiliated with or endorsed by the Keystone RV Company or any of its affiliates in any way. Keystone RV® is a registered trademark of the Keystone RV Company.


All times are GMT -8. The time now is 10:09 PM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2024, vBulletin Solutions, Inc.