Reply
 
Thread Tools Search this Thread Display Modes
 
Old 09-09-2014, 07:12 PM   #1
Rivet Master
 
interstateflyer's Avatar
 
2017 25' International
Currently Looking...
Currently Looking...
Los Osos , California
Join Date: Jun 2004
Posts: 871
Images: 7
Michelin LT 275 20s to Replace Goodyear SRA 275 20s....Pressures?

My 2014 Dodge RAM 1500 5.7 Hemi just hit 20K miles and I'm considering replacing the OEM Goodyear SR-A P275/60 R20 Standard Load tires with Michelin M/S2 LT275/65 R20 LR Es.

The door jamb sticker says to inflate the tires to 39 psi. The Goodyear sidewall say 44 psi max. I've been inflating to 44 psi while towing.

I've run the Michelin LTs at or near the max of 80 psi indicated on their sidewall on trucks and trailers.

Should I completely disregard the 39 psi door jamb guideline and go somewhere nearer 80 psi on the Michelins?
__________________

__________________
2017 Airstream International Serenity 25FB
2016 RAM 2500 Crew Cab Cummins 6.7 Diesel
interstateflyer is offline   Reply With Quote
Old 09-09-2014, 07:33 PM   #2
4 Rivet Member
 
2017 26' Flying Cloud
Missouri Valley , Iowa
Join Date: Sep 2008
Posts: 338
I have the LR E Michelins on both trailers and my '10 F150. I run all of them at 80 PSI per my tire man. He's been in the industry for 35 yrs. He says flex at lower than max inflation will shorten tire life due to more heat. The F 150 had P tires when new and I had troubles so I bit the bullet at 16K mi on them and replaced with the Michelins. I now have 60K + miles on them and will trade the truck or replace them with probably 45% tread left.
Dan
__________________

__________________
Farmer Dan is offline   Reply With Quote
Old 09-10-2014, 07:31 AM   #3
CapriRacer
 
CapriRacer's Avatar
 
I'm in the , US
Join Date: Sep 2012
Posts: 624
First, I am not a fan of replacing P type tires with LT type tires - and the reason will be clear in a moment.

In order to carry the same load a P275/60R20 does at 39 psi, an LT275/65R20 needs to use 47 psi.

Now since the vehicle's spring, shock damping, and sway bars were designed around a 39 psi tire spring rate, using 47 psi is going to not only cause a rough ride, but the vehicle will tend to overcompensate when encountering a bump, making the vehicle slightly less predictable, handling-wise.
__________________
CapriRacer is offline   Reply With Quote
Old 09-10-2014, 09:29 AM   #4
Full Time Adventurer
 
BoldAdventure's Avatar
 
2007 27' International CCD FB
Nomadic , USA
Join Date: Jul 2013
Posts: 2,743
That's fine, a lot of guys on the Ramforum have gone up to that size tire and all usually inflate to somewhere near 55psi. You can disregard the door jam. I myself plan on switching to that size shortly.

The Goopyears are a terrible tire, and anyone with a Ram who has driven on them knows they kind of suck when towing. I don't have a problem with them when not towing, but they are soft and tend to float.
__________________
Family of 4 living, working & exploring the USA in our Airstream.
OUR BLOG | FACEBOOK | INSTAGRAM
BoldAdventure is offline   Reply With Quote
Old 09-10-2014, 09:29 AM   #5
4 Rivet Member
 
1987 25' Sovereign
Oregon , Ohio
Join Date: Nov 2010
Posts: 491
Will rims designed to handle 47 psi be overstressed at 80 psi?
__________________
msmcv51 is offline   Reply With Quote
Old 09-10-2014, 09:33 AM   #6
Full Time Adventurer
 
BoldAdventure's Avatar
 
2007 27' International CCD FB
Nomadic , USA
Join Date: Jul 2013
Posts: 2,743
Quote:
Originally Posted by msmcv51 View Post
Will rims designed to handle 47 psi be overstressed at 80 psi?
Depends on which rims. The Chrome clads I have are rated to 65psi max.
__________________
Family of 4 living, working & exploring the USA in our Airstream.
OUR BLOG | FACEBOOK | INSTAGRAM
BoldAdventure is offline   Reply With Quote
Old 09-10-2014, 10:29 AM   #7
Rivet Master
 
Wayward's Avatar
 
2006 25' Safari FB SE
Cary , North Carolina
Join Date: Mar 2007
Posts: 803
I have not figured out any formula for this.

I always put larger and higher load rating tires on my trucks even adding spring leafs or small lifts to get as much tire as I can.

Here is what I do now....

- Ask the tire installer to inflate them 20% below the maximum pressure and take a short drive out of the shop.

- Look carefully at the initial wear pattern on the tread surface. When the tire is new it is fairly easy to see if the tires are touching closer to the "crown" or on the outside edges.

- I then go up or down 5 psi or so, as needed and recheck after another short trip

- After a few iterations it eventually gets close. After a few thousand miles they might show a bit of more permanent wear pattern and I make the final adjustment before rotating the tires.
__________________
2006 Safari SE FB
2000 F150 4.2L
2011 F250 6.2L
Raleigh, NC
Wayward is offline   Reply With Quote
Old 09-10-2014, 01:55 PM   #8
Rivet Master
 
2005 19' Safari
GLENDALE , AZ
Join Date: Aug 2004
Posts: 2,441
We have a 2008 Tundra with 275/65x18 tires. OEM was BFGoodrich Rugged Trails, a "P" (passenger car) tire with max pressure = 44 psi. They had a soft ride, but were squishy when towing, even when inflated to 44 psi. Plus, they wore out quickly, even though our pickup isn't driven hard.

I replaced the BFGs with same size Michelin LTX M/S2, load range "E" LT tires. I now run 55 psi in the fronts so they wear more evenly, and 65 in the rears when towing (which is about 90% of the time). With the new tires and higher pressures, I don't think the ride is significantly harsher. However, there is a noticeable increase in road feel through the steering wheel; and handling is greatly improved.

It does ride a little more like a truck, and a little less like a passenger car; but it's still rides like a limo when compared to "Hal", our old, 1978, Chevy, 3/4-ton crewcab pickup.

I wouldn't run 80 psi. However, I think you'll find that your pickup will handle better, and your new Michelins will wear more evenly; if you use 44 psi as a minimum, and add a few psi in proportion to your load conditions in accordance with tire charts.
__________________
Phoenix is offline   Reply With Quote
Old 09-10-2014, 10:51 PM   #9
Rivet Master
 
interstateflyer's Avatar
 
2017 25' International
Currently Looking...
Currently Looking...
Los Osos , California
Join Date: Jun 2004
Posts: 871
Images: 7
How do you determine the max pressure for your wheels ?


Sent from my iPhone using Airstream Forums
__________________
2017 Airstream International Serenity 25FB
2016 RAM 2500 Crew Cab Cummins 6.7 Diesel
interstateflyer is offline   Reply With Quote
Old 09-11-2014, 12:30 AM   #10
Rivet Master
 
Wayward's Avatar
 
2006 25' Safari FB SE
Cary , North Carolina
Join Date: Mar 2007
Posts: 803
Quote:
Originally Posted by interstateflyer View Post
How do you determine the max pressure for your wheels ?
Should be stamped or cast on the inside of the rim.

I believe it is the max pressure to be used during mounting when stresses are high, not for normal driving inflation.
__________________
2006 Safari SE FB
2000 F150 4.2L
2011 F250 6.2L
Raleigh, NC
Wayward is offline   Reply With Quote
Old 09-11-2014, 03:00 AM   #11
Well Preserved

 
1993 21' Sovereign
Colfax , North Carolina
Join Date: Jun 2003
Posts: 20,193
Quote:
Originally Posted by Wayward View Post
Should be stamped or cast on the inside of the rim.

I believe it is the max pressure to be used during mounting when stresses are high, not for normal driving inflation.
I am pretty sure that's not the case.
Every tire I've seen has a warning not to exceed 40 psi when mounting.
If a wheel has a max pressure stamped on it, that is the max pressure for operating.
__________________
Meddle not in the affairs of dragons, for you are crunchy, and taste good with ketchup.
Terry
overlander63 is offline   Reply With Quote
Old 09-11-2014, 04:41 AM   #12
Refugee from Napa, CA
 
Photobum's Avatar
 
2015 25' FB Flying Cloud
Madison , South Dakota
Join Date: Apr 2014
Posts: 502
Images: 5
Blog Entries: 1
I run my Michelins at 65psi on my F-150, same as the trailer tires. No problems and having the ten plys makes me feel safer. I have 170M miles on my truck and am on my third set of tires. They wear much longer and better than the original OEM tires that I replaced at 350 miles.
__________________
www.vincentgoetz.com
Photobum is offline   Reply With Quote
Old 09-11-2014, 05:41 AM   #13
CapriRacer
 
CapriRacer's Avatar
 
I'm in the , US
Join Date: Sep 2012
Posts: 624
Quote:
Originally Posted by Wayward View Post
Should be stamped or cast on the inside of the rim.......
There is no requirement that wheels have such stamping and many do not. So don't be surprised if you can't find a maximum pressure stamped anywhere on the wheel.
__________________
CapriRacer is offline   Reply With Quote
Old 09-11-2014, 08:42 PM   #14
Rivet Master
 
interstateflyer's Avatar
 
2017 25' International
Currently Looking...
Currently Looking...
Los Osos , California
Join Date: Jun 2004
Posts: 871
Images: 7
Quote:
Originally Posted by CapriRacer View Post
First, I am not a fan of replacing P type tires with LT type tires - and the reason will be clear in a moment.

In order to carry the same load a P275/60R20 does at 39 psi, an LT275/65R20 needs to use 47 psi.

Now since the vehicle's spring, shock damping, and sway bars were designed around a 39 psi tire spring rate, using 47 psi is going to not only cause a rough ride, but the vehicle will tend to overcompensate when encountering a bump, making the vehicle slightly less predictable, handling-wise.
Where can I read more about the negative impact of handling when using a stiffer tire with higher pressures?
__________________

__________________
2017 Airstream International Serenity 25FB
2016 RAM 2500 Crew Cab Cummins 6.7 Diesel
interstateflyer is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Michelin LTX M/S versus Michelin LTX M/S 2 - Which Would You Choose? doutterson Tires 40 10-23-2016 10:08 PM
Goodyear Wrangler SRA LT265/60R20 SteveH Tow Vehicles 21 08-11-2014 05:43 AM
Tires: other than Michelin & Goodyear, what do you think? RAG General Motorhome Topics 25 03-05-2013 03:18 PM
275,500,00 obo Aerowood Off Topic Forum 8 09-01-2010 03:29 PM
Want to meet in Mi. sept 12-14 Yankee springs SRA? memgrove2000 Forum Rallies & Meet Ups 7 09-16-2008 03:37 PM


Virginia Campgrounds

Reviews provided by




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 04:46 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.

Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.