Reply
 
Thread Tools Search this Thread Display Modes
 
Old 03-01-2013, 12:02 PM   #29
Rivet Master
Airstream Dealer
 
Inland RV Center, In's Avatar
 
Corona , California
Join Date: Feb 2002
Posts: 16,499
Images: 1
Quote:
Originally Posted by CapriRacer View Post
2 thoughts:

Next to my office is a room chock full of wheels - and most of them are OE wheels - and I don't think there is a one that has max pressure stamped on the wheel.

If max pressure were so important, wouldn't that be stamped on the wheel, and not on a label that can be removed - regardless of quality?
I have no idea since I am not into manufacturing wheels.

Safety is always my concerns.

I, personally, would have "ZERO" faith in any wheel not properly marked. Therefore, I will not provide such a wheel to customers that trust us.

Andy
__________________

__________________
Inland RV Center, In is offline   Reply With Quote
Old 03-01-2013, 01:12 PM   #30
Moderator dude
 
Action's Avatar

 
1966 26' Overlander
Phoenix , Arizona
Join Date: Apr 2002
Posts: 6,068
Images: 13
Quote:
Originally Posted by Wazbro View Post
Well 1 reason is that it has been reported that tires lose as much as 30% of their strength in 5 years so a D or E tire inflated to the pressure of a C would still have the capacity of a new C rated tire after 5 years.
That is interesting, I have never heard of this. And in my opinon, after being mounted for 5 years the service life of any tire is approaching the end no matter what tread is left.

My daily driver's get about 13 to 15,000 miles a year in usage. At the end of 5 years that is 75,000 miles. Yikes. Currently because of my life's events, I have a trailer* that has brand new tires in July of 2009 with may be 4000 miles of useage. (And that is being generous) I suspect these tires will be shot in another couple of years due to age. This trailer will get used this year as my life's events have changed again to free up some time. At least this is the plan. I live in Phoenix where sun is a big factor. Those tires have always been covered to block out UV. No cracks when last checked.

With that stated I have this from RMA https://www.rma.org/RMA%20Tire%20Ser...cationID=11453

And from Tire Rack Tire Tech Information - Tire Aging Part #1 While there is not a published US standard for end of tire service life based on age however Tire Rack concludes that 6 to 10 years is the limit. See the bottom of that article.

If a tire loses 30% of it's strength (or almost a third) in my opinon that tire is no longer suited for the load it was designed to handle. Or it is beyond it's service life! I would strongly question that thought process. And if that is correct, does one inflate an "E" rated tire to max less the 30% loss to get a "C" rated capacity after 5 years of usage?

*That dual axle 28' trailer supports about 7300 pounds of load. The tires (14" rim) have a maxload rating of 1880. So my max load capacity for the tires is 7520 #s. Razor thin margin in my opinion.

>>>>>>>>>>>>>>>Action
__________________

__________________
1966 Mercury Park Lane 4 DR Breezeway 410 4V, C-6, 2.80 - Streamless.
1966 Lincoln 4 door Convertible 462 4V 1971 Ford LTD Convertible 429 4V Phoenix ~ Yeah it's hot however it's a dry heat!
Action is offline   Reply With Quote
Old 03-02-2013, 06:50 AM   #31
CapriRacer
 
CapriRacer's Avatar
 
I'm in the , US
Join Date: Sep 2012
Posts: 624
Quote:
Originally Posted by Action View Post
I have a similar question and slightly different.

If the load capacity is "X" is with standard steel wheel and "C" rated tire inflated to max stamped on tire. What advantage is accomplisted by changing to a "D" or "E" rated tire and inflating to less than max ? (and still acceptable for the rim.)

From what was stated above there is no greater capacity in load based on lower inflation rate of "D" or "E" rated tire. And may be the answer is more complex than I state the question just not sure.

>>>Action
I think the advantage is that you are starting with a tire of greater potential, and not using that potential. This has to do with "Fatigue" - which I will explain in the next post.
__________________
CapriRacer is offline   Reply With Quote
Old 03-02-2013, 07:17 AM   #32
CapriRacer
 
CapriRacer's Avatar
 
I'm in the , US
Join Date: Sep 2012
Posts: 624
Quote:
Originally Posted by Wazbro View Post
Well 1 reason is that it has been reported that tires lose as much as 30% of their strength in 5 years.......
I have a problem with the way this is stated. No, I don't have a problem with Wazbro - or whoever extracted this. I have a problem with whoever originallt stated it that way. Here's why:

"Fatigue". Here's a Wikipedia article about it:

http://en.wikipedia.org/wiki/Fatigue_(material)

About 1/3 down the page is an S-N curve (Stress vs Number of cycles). S-N curves look very similar regardless of the material in question.

What the S-N curve says - among many things - is that the number of cycles to failure is a function of the stress level. So something with a lower stress level will have more cycles before it fails - like using a Load Range D in place of a Load Range C.

The S-N curve also says that you can estimate the remaining cycles to failure. - And I think that is what the statement in question is trying to express. Unfortunately, it is stated in such an easy to understand way that it becomes inaccurate and confusing.

Please note, that fatigue occurs in everything produced. It's just that tires have a pretty well defined "life".

I should also point out that the S-N curve does NOT account for the deteriortion caused by the environment - oxygen, ozone, UV rays, etc. So even unused tires become unusable after a length of time (depending on the environment)
__________________
CapriRacer is offline   Reply With Quote
Old 03-02-2013, 09:55 AM   #33
Rivet Master
 
1988 32' Excella
Robbinsville , New Jersey
Join Date: May 2012
Posts: 1,010
Quote:
Originally Posted by CapriRacer View Post
I have a problem with the way this is stated. No, I don't have a problem with Wazbro - or whoever extracted this. I have a problem with whoever originallt stated it that way. Here's why:

"Fatigue". Here's a Wikipedia article about it:

http://en.wikipedia.org/wiki/Fatigue_(material)

About 1/3 down the page is an S-N curve (Stress vs Number of cycles). S-N curves look very similar regardless of the material in question.

What the S-N curve says - among many things - is that the number of cycles to failure is a function of the stress level. So something with a lower stress level will have more cycles before it fails - like using a Load Range D in place of a Load Range C.

The S-N curve also says that you can estimate the remaining cycles to failure. - And I think that is what the statement in question is trying to express. Unfortunately, it is stated in such an easy to understand way that it becomes inaccurate and confusing.

Please note, that fatigue occurs in everything produced. It's just that tires have a pretty well defined "life".

I should also point out that the S-N curve does NOT account for the deteriortion caused by the environment - oxygen, ozone, UV rays, etc. So even unused tires become unusable after a length of time (depending on the environment)
Thank you for the way you stated that.

I saw this listed a couple of places, of coarse now I can't find it. I repeated the statement to show having reserve strength would add to safety. I believe you are probably right that it was oversimplified.

IMHO way to often information seems to be dumbed down for the media and then they dumb it down more or only report the part they understand and/or agree with, sometimes past the point of making the information useless to making it misleading.
__________________
Wazbro is offline   Reply With Quote
Old 03-02-2013, 02:13 PM   #34
Top
Always learning
 
Top's Avatar
 
1972 29' Ambassador
1962 19' Globetrotter
1951 21' Flying Cloud
Central , Texas
Join Date: Oct 2010
Posts: 2,779
Images: 24
Blog Entries: 2
Send a message via Yahoo to Top
New DEXSTAR wheels

Quote:
Originally Posted by Inland RV Center, In View Post
Quality wheels always have either a label with the maximum air pressure on them, or the wheel is stamped.

Andy
Quote:
Originally Posted by CapriRacer View Post
2 thoughts:

Next to my office is a room chock full of wheels - and most of them are OE wheels - and I don't think there is a one that has max pressure stamped on the wheel.

If max pressure were so important, wouldn't that be stamped on the wheel, and not on a label that can be removed - regardless of quality?
I have seen wheels (old) with a max pressure stamped on them. Usually it is on the back side of the rim somewhere a normal owner would never see it. I don't know what the rim manufacturers association rules are on this, but it seems that labeling requirements may have changed. I think an inquiry to DEXSTAR would enlighten us all.

I have replaced a few wheels lately. The picture below is a new steel wheel from DEXSTAR, made in the USA. I think most people would find this to be a quality wheel. The only markings it has are on a label on the rim next to the valve stem. No mention of a maximum pressure anywhere.
Click image for larger version

Name:	IMAG2231.jpg
Views:	47
Size:	202.2 KB
ID:	180100
The label is very clear about the load and proper torque application to the lug nuts.
This made in China wheel is on a 2007 25' International OB.
Click image for larger version

Name:	IMAG0811.jpg
Views:	47
Size:	253.5 KB
ID:	180101
This rim has a LR-E tire on it. Seems like a lot to me for a trailer with a #7,000 GAWR.
__________________
Lance

Work is never done, so take time to play!
Top is offline   Reply With Quote
Old 03-02-2013, 06:40 PM   #35
Moderator dude
 
Action's Avatar

 
1966 26' Overlander
Phoenix , Arizona
Join Date: Apr 2002
Posts: 6,068
Images: 13
TOP, that wheel is not steel either.

For a stamped steel wheel they have come in 2 flavors since split rims. Rivited and welded. Older style the center was rivited and most recent wheels the center is welded.
Assume max trailer load of 7400 #s, if a rim was designed for a certain load capacity, let's say 2600 #'s per wheel. And the end user has load range "C" tires (6 ply rating) installed that has a load capacity of less than 1900 #'s at max inflation 50 psi. If the end user were to upgrade to a load range "D" (8 ply rating) with a max load capacity of just shy of 2400# at max pressure of 65 psi is there an issue?

(Tires now have a load index from 71 to 110 so in the above example moving from a load index 102 = 1874# to aload index 110 = 2337#)


>>>>>Action
__________________
1966 Mercury Park Lane 4 DR Breezeway 410 4V, C-6, 2.80 - Streamless.
1966 Lincoln 4 door Convertible 462 4V 1971 Ford LTD Convertible 429 4V Phoenix ~ Yeah it's hot however it's a dry heat!
Action is offline   Reply With Quote
Old 03-02-2013, 07:01 PM   #36
Top
Always learning
 
Top's Avatar
 
1972 29' Ambassador
1962 19' Globetrotter
1951 21' Flying Cloud
Central , Texas
Join Date: Oct 2010
Posts: 2,779
Images: 24
Blog Entries: 2
Send a message via Yahoo to Top
I'm sorry I didn't mean to confuse anyone. The second pic is an aluminum rim from a 2007 25' International. The first pic is a pic of the sticker on a new welded center STEEL wheel. Here is a pic of the whole shebang.

Click image for larger version

Name:	IMAG2078.jpg
Views:	53
Size:	233.6 KB
ID:	180133

No. No issue at all.

I just wanted to point out that not all wheels have a "Max Pressure" stamp or tag on them.
__________________

__________________
Lance

Work is never done, so take time to play!
Top is offline   Reply With Quote
Reply

Tags
1967


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 12:27 PM.


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.