Go Back   iRV2 Forums > MOTORHOME FORUMS > MH-General Discussions & Problems
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 03-16-2010, 01:54 PM   #15
Senior Member
 
RVee'r's Avatar
 
Vintage RV Owners Club
Fleetwood Owners Club
Join Date: Nov 2009
Location: Southern California
Posts: 150
Quote:
Originally Posted by Tireman9 View Post
Bob, I'm not familear with Hawkshead but am wondering about the accuracy of their reading. Given that all tires leak from 1.5% to 3.5% inflation each month, you would have had to over-inflate your tires quite a bit to still be above the minimum inflation needed to carry the load based on actual tire loading.
TPMS are not a substitute for checking and adding the needed air each month. What they do is warn you of unexpected rapid (faster than 5% a month) air leakage.
Good point. I'll check the pressures with a gauge and report back.

Bob
__________________

__________________
'87 Fleetwood Tioga Arrow

If you're in a hurry, you shouldn't be RV'ing
RVee'r 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 03-16-2010, 03:59 PM   #16
Senior Member
 
AFChap's Avatar
 
Winnebago Owners Club
Spartan Chassis
Join Date: Aug 2002
Location: ...hopefully on the road!
Posts: 4,719
Quote:
can't see how it's true that ALL tires loose between 1.5 and 3% of their pressure every month based on the experience with my coach.
Me either ...I am pretty picky about keeping pressures accurate and rarely have to add air other than due to seasonal temp change in the Fall. I DO have to add air to my very low volume high pressure bicycle tires fairly frequently, but not the MH or toad tires ...knowing how air gets out of the bicycle tires I pay close attention to the MH tires, but I just don't see frequent need to aid air there...
__________________

__________________
Paul (KE5LXU) ...was fulltimin', now parttimin'
'03 Winnebago UA 40e / '05 Honda Odyssey toad
AFChap is offline   Reply With Quote
Old 03-16-2010, 08:39 PM   #17
Registered User


 
Monaco Owners Club
Join Date: May 2009
Posts: 3,198
Quote:
Originally Posted by AFChap View Post
Me either ...I am pretty picky about keeping pressures accurate and rarely have to add air other than due to seasonal temp change in the Fall. I DO have to add air to my very low volume high pressure bicycle tires fairly frequently, but not the MH or toad tires ...knowing how air gets out of the bicycle tires I pay close attention to the MH tires, but I just don't see frequent need to aid air there...
I'm betting that 1.5 to 3% is refering to volume?
not pressure?
__________________
JimM68 is offline   Reply With Quote
Old 03-16-2010, 08:43 PM   #18
RV Mutant #14
 
Wayne M's Avatar


 
Winnebago Owners Club
Texas Boomers Club
Freightliner Owners Club
iRV2 No Limits Club
Join Date: Aug 2008
Location: Texas
Posts: 12,203
Today, I had the tires inspected by A & A Tire, in Kerrville, TX. I pulled in, was directed to the back yard, and immediately a tire man was there taking the duals off the street side. They were inspected, and no damage was evident. I asked, and they supplied, straight valve extensions. They also stated that there was a problem with "braided" extensions leaking. About 45 minutes to an hour later, I was back on the road. It cost me $10.35 for the valve extensions, and no other charges. Kerrville is not that far off of I-10, so if you are in the need for tires, or a check, give them a holler. It may not be as cheap as mine was, but the service is great.

Check the web site for A & A Tires, and the RV section. They have a 24 hour service with a 150 mile radius.

A & A Tire Service, Inc.
2934 Junction Hwy., Kerrville, Texas 78028
Office 830 367 4640
►Toll Free (TX only) 800 341 0409
►Fax 830 367 4929
__________________
Wayne MSGT USMC (Ret) & Earlene (CinCHouse)
2015 Winnebago Tour 42QD
RVM14
It is what it is, and then it is what you make of it.
Wayne M is offline   Reply With Quote
Old 03-16-2010, 09:07 PM   #19
Senior Member
 
Elkhartjim's Avatar


 
Newmar Owners Club
Texas Boomers Club
Freightliner Owners Club
Join Date: Jul 2008
Location: Don't mess with Texas
Posts: 3,116
Wayne, don't you know about the bat that all "truckers" carry?
__________________
Jim with Judy
2017 Newmar Ventana 4369, 2005 Jeep Wrangler (Rock Crawler), 2016 Jeep Wrangler (Mall Crawler)
Elkhartjim is offline   Reply With Quote
Old 03-17-2010, 01:13 PM   #20
Senior Member
Commercial Member
 
Join Date: Mar 2010
Location: Akron, Ohio
Posts: 1,477
Quote:
Originally Posted by RickO View Post
I installed the Doran 360 over a year ago and have been very happy with it but I still kept my thumper and occasionally give each tire a rap. I understand the logic of checking tires manually and using the TPMS only for a warning system... but practically speaking it's a real bear to do. I need to go with the dually extenders and replace the valves on my fronts to make the sensors easier to remove for manual checking.

I really can't see how it's true that ALL tires loose between 1.5 and 3% of their pressure every month based on the experience with my coach. For the past 18 months I've only had to add air to one tire. If I had lost 2%/month I would have lost nearly 40lbs of air from each tire and that just hasn't happened.
It has been demonstrated that "Thumpers" do not work. I am aware of demonstrations where experienced truck drivers were invited to "Thump" a few tires and then say how much air was in the tires. No onw was correct and some were off by 25psi.

RE Pressure & Temperature & time

The Percent loss measurement done in the tire industry is at constant temperature and constant barometric pressure measured continuously over a 6 month period. Pressure is taken with a transducer so there is no air loss. Most OE passenger tires have to demonstrate less than 2% per month so they usually run about 1.5%.
I have heard figures from others in the tire industry that 3% is not unreasonable.

If you start with 100psi you would loose maybe 2 psi the first month and less each month therafter. IF the temperature was the same. I assume you are using a calibrated digital pressure gauge. Correct?

I doubt that you will find an experienced tire engineer who is not willing to say that all tires loose some air each month.

Suggest you check "Ideal Gas law" PV=NRT which is reasonable for tires. Air is about 80% Nitrogen so works for tires inflated with Air or that have been inflated to the 96% Nitrogen.
Volume does not change significantly and N does not change for the air in the tire over time. R= 8.314472 JK−1mol−1
So if you want to do the math go ahead but I prefer to use a rule of thumb for pressure vs temp is 1 psi per 10F change. Hot = increase. I have heard others claim as much as 2 psi per 10F. I think it depends on how dry the air is.
__________________
Retired Design & Quality Tire Eng. Read my tire blog RVTireSafety.NET to learn more about RV tires, valves & wheels. Read THIS post on why Tires Fail
Tireman9 is offline   Reply With Quote
Old 03-17-2010, 01:18 PM   #21
Senior Member
Commercial Member
 
Join Date: Mar 2010
Location: Akron, Ohio
Posts: 1,477
Quote:
Originally Posted by Wayne M View Post
Today, I had the tires inspected by A & A Tire, in Kerrville, TX. I pulled in, was directed to the back yard, and immediately a tire man was there taking the duals off the street side. They were inspected, and no damage was evident..........
Glad you had them inspected.
They did dismount each tire and used X-ray or Sherograph inspection to be sure there was no damage internal to the srtucture of the tires...Right?
__________________
Retired Design & Quality Tire Eng. Read my tire blog RVTireSafety.NET to learn more about RV tires, valves & wheels. Read THIS post on why Tires Fail
Tireman9 is offline   Reply With Quote
Old 03-17-2010, 01:20 PM   #22
Moderator Emeritus
 
Mike Canter's Avatar


 
Join Date: Apr 2008
Location: Freeport, ME
Posts: 4,707
I agree that tires will always loose air. The problem is that we RVers do not have a contant environment to measure in. Our temperature and barometric pressure is always changing. Same goes for oil in a motor. Some guys say their motor does not use oil. It has to use oil or the cylinder walls and valve guides are going to wear out. The problem again is the measurement environment of having the same amount of oil drain back from the motor into the pan and having the motor level and the temperature of the oil.
__________________
Mike Canter
"Gunner" USN Retired, Airdale
2004 Monaco Signature 44' Conquest. Detroit 60
Mike Canter is offline   Reply With Quote
Old 03-17-2010, 01:22 PM   #23
Moderator Emeritus
 
Mike Canter's Avatar


 
Join Date: Apr 2008
Location: Freeport, ME
Posts: 4,707
What would worry me about that tire being flat was the fact that the bead was broken loose and the tire was away from the rim. To me that indicates that tire was driven with no air in it. If you let the air out of a stationary tire it normally will not pull away from the rim.
__________________
Mike Canter
"Gunner" USN Retired, Airdale
2004 Monaco Signature 44' Conquest. Detroit 60
Mike Canter is offline   Reply With Quote
Old 03-17-2010, 03:06 PM   #24
RV Mutant #14
 
Wayne M's Avatar


 
Winnebago Owners Club
Texas Boomers Club
Freightliner Owners Club
iRV2 No Limits Club
Join Date: Aug 2008
Location: Texas
Posts: 12,203
The tire was apparently driven for 20 miles or less without air.

No, there was no electronic inspection.

You can stop scaring me now - I'm going to live with the decision, and I hope it is a right one. Don't follow me to closely behind.
__________________
Wayne MSGT USMC (Ret) & Earlene (CinCHouse)
2015 Winnebago Tour 42QD
RVM14
It is what it is, and then it is what you make of it.
Wayne M is offline   Reply With Quote
Old 03-17-2010, 05:40 PM   #25
Moderator Emeritus
 
RickO's Avatar


 
Join Date: Jan 2007
Location: Litchfield Park, Arizona
Posts: 10,530
Thanks for the insights Tireman9. I'll only add that:

1) no, I don't use a calibrated, digital tire gauge.
2) yes, I'll agree that "thumpers don't 'work'". My only reason for mentioning it was that I can detect a tire which is flat or very low.
3) I certainly wouldn't argue with a "reputable tire engineer" if they told me that all tires lose "some" air every month. My experience just doesn't support that they all lose 1.5 to 2%/month.
4) when faced with a choice between math and rule of thumb... I'll take math.
__________________
Rick, Nancy, Peanut & Lola our Westie Dogs & Bailey the Sheltie.

2007 Itasca Ellipse 40FD
RickO is offline   Reply With Quote
Old 03-17-2010, 06:00 PM   #26
Moderator Emeritus
 
Mike Canter's Avatar


 
Join Date: Apr 2008
Location: Freeport, ME
Posts: 4,707
Wayne, sorry didn't mean to scare you but it is better to be warned. When my rear tire went I first had a severe vibration from the back. Didn't know what it was and actually asked by wife to walk back and see what she thought. Big mistake because then it came apart. Looking back I think I would have had time to pull over from when the vibration first started and the belt came off. I was lucky that it was the inner tire so it did not do body damage. It took me some time to pull the belt out from the suspension.
You will be OK.
__________________
Mike Canter
"Gunner" USN Retired, Airdale
2004 Monaco Signature 44' Conquest. Detroit 60
Mike Canter is offline   Reply With Quote
Old 03-17-2010, 06:06 PM   #27
Member
 
Big Dan's Avatar
 
Damon Owners Club
Workhorse Chassis Owner
Join Date: Nov 2009
Posts: 48
Thanks for the reminder. I can't afford a tire pressure monitor, so it does me a lot of good when I read a post such as yours. Gives me a little nudge in the right direction, if you will.

I'm glad it was something (relatively) simple and inexpensive for you.
__________________
2000 Damon Challenger 330
We call it "The House Truck."
Big Dan is offline   Reply With Quote
Old 03-17-2010, 07:41 PM   #28
Senior Member
 
RVee'r's Avatar
 
Vintage RV Owners Club
Fleetwood Owners Club
Join Date: Nov 2009
Location: Southern California
Posts: 150
Quote:
Originally Posted by Tireman9 View Post
Bob, I'm not familear with Hawkshead but am wondering about the accuracy of their reading. Given that all tires leak from 1.5% to 3.5% inflation each month, you would have had to over-inflate your tires quite a bit to still be above the minimum inflation needed to carry the load based on actual tire loading.
TPMS are not a substitute for checking and adding the needed air each month. What they do is warn you of unexpected rapid (faster than 5% a month) air leakage.
Well, I checked today and as a matter of fact all six tires were 1-2 pounds less than when I jotted down the original pressure reading from installation. So, that alone means I'll check them before heading out on a trip. The HawksHead readings were consistent with my gauge, meaning, the readings were also lower than originally.

Were talking 16" tires with 60 lbs. of air so it wasn't anything drastic or critical, but it is, however, somewhat significant. Thx Tireman
__________________

__________________
'87 Fleetwood Tioga Arrow

If you're in a hurry, you shouldn't be RV'ing
RVee'r 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
ANYONE ever having to replace RV tires needs to read this!!! leedowney Freightliner Motorhome Chassis Forum 14 03-12-2010 11:54 AM
New/Old Goodyear G670 RV Motorhome Tires Issue jntrox MH-General Discussions & Problems 8 12-01-2009 12:04 PM
Tread wear outer dually tires on F350 Bruce and Jenna Trailer Towing and Tow Vehicles Discussion 18 09-17-2009 09:17 PM
Replacing 5er Tires with Light Truck Tires RKamperRV 5th Wheel Discussion 12 02-10-2008 07:54 AM
Best price is not always the BEST on tires supercub Workhorse and Chevrolet Chassis Motorhome Forum 4 07-18-2007 07:44 PM

» Virginia Campgrounds

Reviews provided by


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 02:15 AM.


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