Notices
LS - 4th Gen (2007-2017) Discussion topics related to the current flagship models LS460, LS460L and LS600H

Cold tire pressure

 
Old 04-24-19, 05:38 PM
  #1  
fwhomeboy
Lead Lap
Thread Starter
 
Join Date: Feb 2017
Location: North Carolina
Posts: 666
Received 53 Likes on 45 Posts
Default Cold tire pressure

I noticed that my tires are at 36 LBS in the morning but after they warm up on my drive to work, they show 41 LBS.
What pressures do you guys see in the morning, compared to after a day of driving. I know I should be at 33 LBS at start up.

Thanks
fwhomeboy is offline  
Old 04-24-19, 05:54 PM
  #2  
jkittlesen
Pole Position
 
jkittlesen's Avatar
 
Join Date: Mar 2019
Location: TX
Posts: 227
Received 26 Likes on 23 Posts
Default

MICHELIN PRIMACY MXM4 19" 33 cold 35 hot.
jkittlesen is offline  
The following users liked this post:
Caflashbob (04-25-19)
Old 04-24-19, 06:21 PM
  #3  
colfax
Driver
 
Join Date: Apr 2018
Location: New Mexico
Posts: 154
Likes: 0
Received 26 Likes on 18 Posts
Default

on the side of the driver's door it says set the pressures at 33, and that would be when the tires are cold like in the morning

heat from the road and outside air raises the tire pressures, this is correct and anticipated to happen when setting them to 33

33 gives a nice soft ride, note that your manual says to set the psi higher when driving at higher speeds on the highway

note that there can be difference between a hand gauge and the TPMS display depending on what altitude you are at

for example I live at 6000 feet altitude, so my hand gauge reads about 4 psi higher than my TPMS dash display

this is because the TPMS things on the rims are calibrated at sea level and there is a difference between relative and atmospheric air pressure

personally I feel 33 is too soft and makes my tires wear faster in the middle, I set mine at 37 psi hand gauge, everybody seems to differ a little on this
colfax is offline  
The following users liked this post:
fwhomeboy (04-24-19)
Old 04-24-19, 06:35 PM
  #4  
fwhomeboy
Lead Lap
Thread Starter
 
Join Date: Feb 2017
Location: North Carolina
Posts: 666
Received 53 Likes on 45 Posts
Default

Originally Posted by colfax View Post
on the side of the driver's door it says set the pressures at 33, and that would be when the tires are cold like in the morning

heat from the road and outside air raises the tire pressures, this is correct and anticipated to happen when setting them to 33

33 gives a nice soft ride, note that your manual says to set the psi higher when driving at higher speeds on the highway

note that there can be difference between a hand gauge and the TPMS display depending on what altitude you are at

for example I live at 6000 feet altitude, so my hand gauge reads about 4 psi higher than my TPMS dash display

this is because the TPMS things on the rims are calibrated at sea level and there is a difference between relative and atmospheric air pressure

personally I feel 33 is too soft and makes my tires wear faster in the middle, I set mine at 37 psi hand gauge, everybody seems to differ a little on this
I'm running 19" P7's. Thanks for your informative post.
fwhomeboy is offline  
Old 04-24-19, 07:44 PM
  #5  
SW17LS
Lexus Fanatic
 
SW17LS's Avatar
 
Join Date: May 2012
Location: MD
Posts: 27,028
Received 680 Likes on 559 Posts
Default

I run mine at 31 cold
SW17LS is offline  
Old 04-25-19, 06:41 AM
  #6  
icon901
Rookie
 
Join Date: Nov 2018
Location: TN
Posts: 89
Received 18 Likes on 10 Posts
Default

I run mine around 37 cold as well.
Bridgetone Turanza Serenity.
icon901 is offline  
Old 04-25-19, 06:48 AM
  #7  
fwhomeboy
Lead Lap
Thread Starter
 
Join Date: Feb 2017
Location: North Carolina
Posts: 666
Received 53 Likes on 45 Posts
Default

Originally Posted by icon901 View Post
I run mine around 37 cold as well.
Bridgetone Turanza Serenity.
How much pressure do you see after they heat up?
fwhomeboy is offline  
Old 04-25-19, 08:23 AM
  #8  
icon901
Rookie
 
Join Date: Nov 2018
Location: TN
Posts: 89
Received 18 Likes on 10 Posts
Default

Originally Posted by fwhomeboy View Post
How much pressure do you see after they heat up?
It will usually get to 38/39 depending on temps/roads/driving. I'm not sure on the accuracy of these sensors as they tend to waver a bit on my car, but generally seem to stay within a pound or three.
icon901 is offline  
Old 04-25-19, 09:48 AM
  #9  
Tec80
Lead Lap
 
Join Date: Sep 2014
Location: IL
Posts: 456
Received 35 Likes on 30 Posts
Default

Tire sidewall and tread flex at the contact patch is responsible for most of the heating. The Ideal Gas Law equation is PV=nRT, so Pressure is dependent on nRT/V. Since n is the number of moles of gas in the tire and is constant, and R (ideal gas constant) and V (the volume inside the tire) are also constant, essentially Pressure is directly proportional to Temperature.
Tec80 is offline  
Old 04-25-19, 03:09 PM
  #10  
ALLBZNS
Driver School Candidate
 
Join Date: Apr 2019
Location: HI
Posts: 12
Likes: 0
Received 1 Like on 1 Post
Default

33/34 cold. Gets up to 36/37 when hot.
ALLBZNS is offline  
The following users liked this post:
fwhomeboy (04-25-19)
Old 04-25-19, 04:06 PM
  #11  
fwhomeboy
Lead Lap
Thread Starter
 
Join Date: Feb 2017
Location: North Carolina
Posts: 666
Received 53 Likes on 45 Posts
Default

Thanks Guys !!!! Now, I have a better view of my options. This group is the ****.
fwhomeboy is offline  
Old 04-26-19, 08:14 AM
  #12  
Kuhan
Pole Position
 
Join Date: Feb 2016
Location: Chicago
Posts: 231
Received 18 Likes on 17 Posts
Default

35 cold 37 hot with outside temps around 65 degrees.
Kuhan is offline  
Old 05-01-19, 11:26 AM
  #13  
Red97tj
Rookie
 
Join Date: Jun 2016
Location: ca
Posts: 57
Likes: 0
Received 3 Likes on 3 Posts
Default

Originally Posted by colfax View Post

note that there can be difference between a hand gauge and the TPMS display depending on what altitude you are at
I'm not sure about all this. I'm in the Bay Area so where I park, it's prob 10ft higher than the Bay water. My car reading is consistently higher than my hand hell. It's normally 2-3psi higher in the car.
I just chalk it up to imprecision of the sensors. At least they are consistent to each other which I care about. As of late I've been paranoid since my old set of tires were wearing unevenly & I want my new set to last as long as possible after realignment. Interestingly, it was just toe that was out.
Red97tj is offline  
Old 05-01-19, 02:02 PM
  #14  
Julez
Lead Lap
 
Join Date: Apr 2006
Location: CA
Posts: 446
Likes: 0
Received 3 Likes on 3 Posts
Default

I set thru a machine all my tires to 32(didnít do spare). The carís sensors measure them: three 33, one 29, spare 45.
Julez is offline  
Old 05-01-19, 09:06 PM
  #15  
Caflashbob
Lead Lap
 
Join Date: Sep 2016
Location: Ca
Posts: 669
Received 44 Likes on 40 Posts
Default

Mxm4 33 cold
Caflashbob is offline  
 


Thread Tools
Search this Thread
Quick Reply: Cold tire pressure


Contact Us - About Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: