cold tire pressure & tempreture - Mercedes Benz SLK Forum

General Discussion Topics must pertain to all 3 generations of SLK - R170, R171 and R172

 
LinkBack Thread Tools
#1 Old 03-14-2012
Registered Users
 
Join Date: Aug 2010
Location: Eastern Ma.
Vehicle: 2010 SLK 300, AMG Sport Pkg
Posts: 623
Country:
Chats: 0
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 25 Post(s)
Thanks: 64
Thanked 24 Times in 22 Posts
(Thread Starter)
cold tire pressure & tempreture

I know tire pressure should be checked "cold".

but should there be any adjustment for ambient temperature?

manual says front 32psi rear 35psi

I set the pressure correctly at a colder ambient and looking at the dash pressure reading ( after driving 100 yards) fronts at 38 and rear at 40. ambient was about 20F higher from when I set them.
bobl is offline  
Sponsored Links
Advertisement
 
#2 Old 03-15-2012
Banned
 
Join Date: Mar 2011
Posts: 7,812
Country:
Chats: 0
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Thanks: 681
Thanked 961 Times in 704 Posts
If you check tyres warm they will always be higher. I think the label inside the petrol flaps tells you by how much.

Just looked + 4 psi
JonB is offline  
#3 Old 03-15-2012
Premium Member
 
Join Date: Feb 2011
Location: Indy
Posts: 2,421
Country:
Chats: 2
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 13 Post(s)
Thanks: 118
Thanked 290 Times in 244 Posts
Quote:
Originally Posted by bobl View Post
I know tire pressure should be checked "cold".

but should there be any adjustment for ambient temperature?

manual says front 32psi rear 35psi

I set the pressure correctly at a colder ambient and looking at the dash pressure reading ( after driving 100 yards) fronts at 38 and rear at 40. ambient was about 20F higher from when I set them.
bobl, "cold" is "ambient". How much time had elapsed from your setting the pressure 'til you drove "100yds" and the ambient temp was 20* higher? When I check and adjust t/p(as needed), I do it just before I start my drive. Also, since apparently you have TPMS, did you compare the dash pressure reading to whatever gauge you used to set the pressure?

"Think as I think," said a man,"Or you are abominably wicked; You are a toad."
And after I had thought about it, I said,
"I will, then, be a toad."(Thank you, Steven Crane)

Think outside the box!
Galo is offline  
 
#4 Old 03-15-2012
Registered Users
 
Join Date: Apr 2007
Location: LAS VEGAS
Vehicle: 07SLK350
Other Toys: 2010 GLK350/2001 RX300
Posts: 902
Country:
Chats: 0
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Thanks: 220
Thanked 102 Times in 86 Posts
Send a message via AIM to QSHIP Send a message via Skype™ to QSHIP
is nitrogren bettter than regular air since race cars use this?
QSHIP is offline  
#5 Old 03-15-2012
Premium Member
 
Join Date: Feb 2011
Location: Indy
Posts: 2,421
Country:
Chats: 2
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 13 Post(s)
Thanks: 118
Thanked 290 Times in 244 Posts
Quote:
Originally Posted by QSHIP View Post
is nitrogren bettter than regular air since race cars use this?
Is it better? Well, if you have easy access to it, it seems to be, but since it isn't available from, say, your home compressor, imo, it isn't worth "switching".

"Think as I think," said a man,"Or you are abominably wicked; You are a toad."
And after I had thought about it, I said,
"I will, then, be a toad."(Thank you, Steven Crane)

Think outside the box!
Galo is offline  
#6 Old 03-15-2012
Registered Users

 
Der Flieger's Avatar
 
Join Date: Sep 2010
Location: Ottawa Ontario
Vehicle: silver/red 06 350
Other Toys: 2011 MB C 300 4matic! and 06 Mazda 3; fly B767-300ER
Posts: 6,796
Country:
Chats: 38
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 123 Post(s)
Thanks: 1,039
Thanked 820 Times in 659 Posts
Garage
Send a message via MSN to Der Flieger Send a message via Yahoo to Der Flieger
PV=nRT
as Temp increases so does Pressure...whether it's the air you're pumping into them (and the compressed air off a hose will be slightly warmer) or after you've warmed them up a bit (or a lot)


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

FUN 4 2
Der Flieger is offline  
The Following User Says Thank You to Der Flieger For This Useful Post:
#7 Old 03-15-2012
Premium Member
 
Join Date: Feb 2011
Location: Indy
Posts: 2,421
Country:
Chats: 2
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 13 Post(s)
Thanks: 118
Thanked 290 Times in 244 Posts
Quote:
Originally Posted by Der Flieger View Post
PV=nRT
as Temp increases so does Pressure...whether it's the air you're pumping into them (and the compressed air off a hose will be slightly warmer) or after you've warmed them up a bit (or a lot)
JJ, if that's aimed at my response, exactly That's why I suggested checking, and adjusting if necessary, just before the driving starts.

I take it you've gotten Kismet out of hibernation

"Think as I think," said a man,"Or you are abominably wicked; You are a toad."
And after I had thought about it, I said,
"I will, then, be a toad."(Thank you, Steven Crane)

Think outside the box!
Galo is offline  
#8 Old 03-15-2012
Sadly Gregg has passed away

 
Gregg's Avatar
 
Join Date: Oct 2009
Location: Southern Illinois
Vehicle: 2009 SLK 350
Other Toys: 2012 ML350, Truck, and Tractor
Posts: 2,432
Country:
Chats: 5
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 17 Post(s)
Thanks: 1,406
Thanked 458 Times in 279 Posts
Garage
Quote:
Originally Posted by Der Flieger View Post
PV=nRT
as Temp increases so does Pressure...whether it's the air you're pumping into them (and the compressed air off a hose will be slightly warmer) or after you've warmed them up a bit (or a lot)
You gotta love a guy who knows his math and isn't afraid to use it! Atta Boy John!


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Gregg is offline  
#9 Old 03-15-2012
Registered Users
 
Join Date: Aug 2010
Location: Eastern Ma.
Vehicle: 2010 SLK 300, AMG Sport Pkg
Posts: 623
Country:
Chats: 0
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 25 Post(s)
Thanks: 64
Thanked 24 Times in 22 Posts
(Thread Starter)
Quote:
Originally Posted by Galo View Post
bobl, "cold" is "ambient". How much time had elapsed from your setting the pressure 'til you drove "100yds" and the ambient temp was 20* higher? When I check and adjust t/p(as needed), I do it just before I start my drive. Also, since apparently you have TPMS, did you compare the dash pressure reading to whatever gauge you used to set the pressure?
the tpms pressure was about the same (maybe 1 psi higher) the day i set the pressure and i drove the same distance,
it was several days days later i noticed the increase at about the same distance
bobl is offline  
#10 Old 03-15-2012
Registered Users
 
Join Date: Aug 2010
Location: Eastern Ma.
Vehicle: 2010 SLK 300, AMG Sport Pkg
Posts: 623
Country:
Chats: 0
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 25 Post(s)
Thanks: 64
Thanked 24 Times in 22 Posts
(Thread Starter)
Quote:
Originally Posted by Der Flieger View Post
PV=nRT
as Temp increases so does Pressure...whether it's the air you're pumping into them (and the compressed air off a hose will be slightly warmer) or after you've warmed them up a bit (or a lot)
i understand that. an increase of 5 psi over a 20F increase in temp seems a lot. the pressure i saw seem to be what i see after driving an hour. i often check the pressure using theTPMS on a trip
bobl is offline  
#11 Old 03-16-2012
Banned
 
Join Date: Mar 2011
Posts: 7,812
Country:
Chats: 0
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Thanks: 681
Thanked 961 Times in 704 Posts
Just walk round and kick them. If they feel hard get in and drive
JonB is offline  
Sponsored Links
Advertisement
 
Reply

  Lower Navigation
Go Back   Mercedes Benz SLK Forum > General Discussion about Mercedes Benz SLKs > General Discussion

Bookmarks

Quick Reply
Message:
Options
Upload your files to MEGAUPLOAD
Upload your images to ImageShack

Register Now



In order to be able to post messages on the Mercedes Benz SLK Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Forum Replies Last Post
How do you know if your car has tire pressure sensors or not? sdshah3 General Discussion 17 02-07-2013 04:48 PM
Tire Pressure Monitor Questions Gregg General Discussion 3 11-01-2010 09:25 PM
Tire Pressure Question Medescape Tires, Wheels, Brakes & Suspension 5 06-26-2010 06:02 PM
New Tire surprise, recommendations ASAP Brian_74 Tires, Wheels, Brakes & Suspension 54 09-28-2009 12:09 AM
Tire pressure sensor Alec SLK R171 General Discussion 7 08-27-2009 07:58 AM

Posting Rules  
You may post new threads
You may 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 On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome
 

Clubs, Garage Plus vBulletin Plugins by Drive Thru Online, Inc.