Go Back   iRV2 Forums > iRV2.com COMMUNITY FORUMS > iRV2.com General Discussion
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
 
Thread Tools Search this Thread Display Modes
 
Old 05-23-2012, 06:56 AM   #1
Member
 
howie-2005's Avatar
 
Winnebago Owners Club
Forest River Owners Club
Join Date: Dec 2009
Location: Seminole, Fl
Posts: 70
Real confusing.

I replaced my 235-80-22.5 tires rated at 4675 lbs. I replaced with 255-70-22.5 with 5070 rating. I pressurized new tires to cold 120 (which is the max rim pressure) and after about 25 florida miles the pressure goes to 135! The coach is empty except for fuel. The GAWR is 15500 at the rear and 9000 front. When I run less pressure (100 - 110) it appears to wear the outside of the tires. Almost as if underinflated! I'm sure confused and could use some help. Is it ok to have them at 135 hot?????
__________________

__________________
Claire & Marty
2008 Winnebago Adventurer, 2007 Saturn Vue.
English Bullies, Roxie 2yrs & Mikey-6ys
howie-2005 is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 05-23-2012, 07:17 AM   #2
Senior Member
 
az bound's Avatar
 
Workhorse Chassis Owner
Join Date: Dec 2007
Location: Surprise Arizona
Posts: 1,993
Its not unusual for tires to gain 15-20 lbs of pressure as they heat up. No need to be concerned about the rim maximum rating, that is also the cold pressure rating.
The proper way to set the cold pressure for tires is to get the four corner weight and use the inflation charts of the manufacturer and adjust accordingly.
__________________

__________________
Harold & Linda
2009 CT coachworks siena 35V
W22 Workhorse 8.1L. Explorer Sport toad,
az bound is offline   Reply With Quote
Old 05-23-2012, 07:38 AM   #3
Senior Member
 
Doug Sage's Avatar
 
Winnebago Owners Club
Workhorse Chassis Owner
Join Date: Mar 2001
Location: Originally from near Portland, OR
Posts: 699
Remember that you are still limited by the axle weight rating. For example, your front axle is rated at 9,000 pounds - not 9,350 with the old tires or 10,140 with the new tires. You should have inflated the old tires to the door plaque recommendation if you did not have the rig weighed and you should use an inflation chart for the new tires. I would suggest adding 5 - 10 pounds pressure to the inflation chart to cover leakage between pressure checks.
__________________
Doug Sage
Full timers roaming the good old US of A
2007 Itasca Suncruiser 38J
2015 Jeep Cherokee Trailhawk
Doug Sage is offline   Reply With Quote
Old 05-23-2012, 08:00 AM   #4
Moderator Emeritus
 
Gary RVRoamer's Avatar


 
Join Date: Jan 2000
Location: Silver Springs, FL. USA
Posts: 18,066
The door placard pressure recommendation is valid only with the original size tires. Once you change size, as the OP did, you need to use the inflation tables to come up with a new "recommended" psi.

A 255/70 that replaces a 235/80 ought to be able to run at about 5 psi less than the previous recommendation, but that can be verified via the inflation tables for the brand and model of tire and finding the psi required to support 9000 lbs with two tires (4500 each). I couldn't find a 255/70 with a 5070 max rating (most are greater than that), so can't offer any help there. What brand and model of tire is it?

Yes, it is ok for them to run at 135 hot - or even 140+. All ratings are with cold pressures.

Are both the front tires wearing on both outer edges when the pressure in under 120? If so, that suggests underinflation. But if either tire is wearing only one edge, than you have a front end alignment problem. Typically a 255/70 should be able to carry your max front axle load at about 100-105 psi.
__________________
Gary Brinck
Former owner of 2004 American Tradition
Home is in the Ocala Nat'l Forest near Ocala, FL
Summers in Black Mountain, NC
Gary RVRoamer is offline   Reply With Quote
Old 05-23-2012, 06:50 PM   #5
Member
 
howie-2005's Avatar
 
Winnebago Owners Club
Forest River Owners Club
Join Date: Dec 2009
Location: Seminole, Fl
Posts: 70
Gary, they are Toyo tires with a single axle rating of 5510 and dual @ 5070. The front tires are fine, just both back seem to wear on the inside and outside (almost like underinflated). I did have just 90 lbs for about 700 miles in all 6 tires, and lately increased to 110 - 120 in the rear. Front I run at 90 with no issues.
Thanks
__________________
Claire & Marty
2008 Winnebago Adventurer, 2007 Saturn Vue.
English Bullies, Roxie 2yrs & Mikey-6ys
howie-2005 is offline   Reply With Quote
Old 05-23-2012, 07:27 PM   #6
Registered User
 
Join Date: Feb 2012
Posts: 346
Do you have the dual wheel clearance for the larger size? Your tires may be rubbing each other at the lower pressure, might cause the unusual wear pattern. They might still be rubbing slightly at the higher pressure which would make the temps go up. Just a thought.
__________________
henderson is offline   Reply With Quote
Old 05-23-2012, 07:44 PM   #7
Member
 
howie-2005's Avatar
 
Winnebago Owners Club
Forest River Owners Club
Join Date: Dec 2009
Location: Seminole, Fl
Posts: 70
@ Henderson.... Plenty of clearance, I can get my arm between the duallies.
__________________
Claire & Marty
2008 Winnebago Adventurer, 2007 Saturn Vue.
English Bullies, Roxie 2yrs & Mikey-6ys
howie-2005 is offline   Reply With Quote
Old 05-23-2012, 11:51 PM   #8
Senior Member
 
slickest1's Avatar
 
Monaco Owners Club
Join Date: Jul 2011
Location: B.C.
Posts: 3,708
Maybe running them at 90lbs was too low and caused the wear you are seeing. Try them at 100lbs for a while and watch what they do. Sometimes the sidewalls will rub on the bottom, where the sidewalls bulge, when driving down the road and over bumps. With more air they will have less chance of doing that.
__________________

__________________
Dennis & Marcie & Captain Hook The Jack Russell,aka PUP, 04 Dodge/Cummins 01 Citation 29.rk fifth wheel.RVM59
slickest1 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


» Virginia Campgrounds

Reviews provided by


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 04:36 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.