Reply
 
Thread Tools Search this Thread Display Modes
 
Old 09-14-2008, 12:38 PM   #519
_
 
. , .
Join Date: Dec 2004
Posts: 8,812
Quote:
Originally Posted by jcanavera View Post
...Auto tires for example, have speed ratings also...
yes they do.

and the speed rating system for passenger car tires,

has NO relationship to how ST tires are labeled, tested or rated.

cheers
2air'
__________________

__________________
all of the true things that i am about to tell you are shameless lies. l.b.j.

we are here on earth to fart around. don't let anybody tell you any different. k.v.
2airishuman is offline   Reply With Quote
Old 09-14-2008, 06:57 PM   #520
Rivet Master
 
SteveH's Avatar
 
2005 39' Land Yacht 390 XL 396
Common Sense , Texas
Join Date: Sep 2007
Posts: 5,311
Discount Tire shows the Goodyear Marathon to have an "R" speed rating, which is up to 106 MPH.

Tire Details - Discount Tire Co.

Tirerack says the country of origin for the Marathons is China.
__________________

__________________
Regards,
Steve
SteveH is offline   Reply With Quote
Old 09-14-2008, 07:35 PM   #521
_
 
. , .
Join Date: Dec 2004
Posts: 8,812
Quote:
Originally Posted by SteveH View Post
Discount Tire shows the Goodyear Marathon to have an "R" speed rating, which is up to 106 MPH....

Tirerack says the country of origin for the Marathons is China.
the speed rating linked is not correct,

someone at d/c tire is confused or mis-keyed this or assumes the R on the side wall indicates something other than Radial tire...

ST tires do NOT receive a passenger tire utog OR speed rating...

ST tires are LOAD RATED/tested at 65 mph, that is NOT a speed rating,

which is a large part of the continual CONFUSION offered here, OVER and OVER and OVER.

by the same players.

How to Read Speed Rating, Load Index & Service Descriptions

UTQG Standards

Air Pressure/Load Adjustment for High Speed Driving

many/most gyms are now made in china, especially those destined 4 the usa.

but the factory origin code is specific and stamped on EVERY tire.

cheers
2air'
__________________
all of the true things that i am about to tell you are shameless lies. l.b.j.

we are here on earth to fart around. don't let anybody tell you any different. k.v.
2airishuman is offline   Reply With Quote
Old 09-14-2008, 08:11 PM   #522
Rivet Master
 
SteveH's Avatar
 
2005 39' Land Yacht 390 XL 396
Common Sense , Texas
Join Date: Sep 2007
Posts: 5,311
2air,

I'm not trying to be argumentative, but even the info from the pages you listed is confusing....from the OTQG Standards:

Quote:
Every tire sold in the United States must be capable of earning a "C" rating which indicates the ability to withstand 85 mph speeds. While there are numerous detail differences, this laboratory test is similar in nature to those used to confirm a tire's speed ratings.
Now granted, they are mostly talking about passenger car tires on the page, but it specifically says "Every tire sold in the United States....", not every passenger car tire.
__________________
Regards,
Steve
SteveH is offline   Reply With Quote
Old 09-14-2008, 08:14 PM   #523
Aluminut
 
Silvertwinkie's Avatar
 
2004 25' Safari
. , Illinois
Join Date: Feb 2003
Posts: 10,334
I dunno... so far liking my Maxxis "D" rated tires with the nylon caps.

Oh, and no pure nitrogen for me...most of what is in the atmosphere that we breathe is mostly made of nitrogen (somewhere about 8 out of 10 atoms). Filtering out the water is the key when putting regular air from the air hose to top off yer tires....

Most of what folks around here that "sell" tires filled with pure nitrogen or nitrogen filling services, are based on pure nitrogen's larger molecules than that mixed with 2 atoms of oxygen. Oxygen molecules from what I understand are smaller and, tires, being somewhat porous, allows these smaller molecules to escape over time far easier than the larger nitrogen molecules, but heck, what the hell do I know, I flunked math, algebra, and barley even passed biology and NEVER took chemistry, but those out there who have and know more than what I've read on the subject could easily say if I'm even remotely right or clearly wrong.
__________________
Computers manufactured by companies such as IBM, Compaq and millions of others are by far the most popular with about 70 million machines in use worldwide. Macintosh fans note that cockroaches are far more numerous than humans and that numbers alone do not denote a higher life form. -NY Times 11/91
Silvertwinkie is offline   Reply With Quote
Old 09-14-2008, 08:15 PM   #524
4 Rivet Member
 
Currently Looking...
holland , Michigan
Join Date: Oct 2007
Posts: 436
Images: 1
I took off the canadian made marathons dated 04 and put on chinese made marathons and left friday for the west coast. They made it to colorado and for some reason the trailer seems to handle better?? Anyway, fingers crossed, I checked every stop and they were running very cool and no problems. Could it be these things are better? I notice they have a scuff guard on the side wall. Anyway, still paranoid.
__________________
safari 28 is offline   Reply With Quote
Old 09-14-2008, 08:34 PM   #525
_
 
. , .
Join Date: Dec 2004
Posts: 8,812
twink'

the 'small molecules leak theory is a real thing turned, applied-myth regarding tires, but mrs. malaprop would be proud...

Quote:
Originally Posted by SteveH View Post
...I'm not trying to be argumentative, but even the info from the pages you listed is confusing....from the OTQG Standards...
steve...

not to worry, your posting isn't argumentative at all...

and there's nothing bad about a little online argument, so long as it's not made personal...

and u don't reach INTO the 'puter screen...

i agree the paragraph is confusing IF you apply it to every tire made,

(besides that "C" is actually a temperature rating (the temps that are typical at 85 mph) not a speed ratingl

but they are referencing UTOG rated tires only, and ST tires aren't utog rated...

NONE of the passenger car OR light truck tire standards apply to ST tires...

the speed ratings and UTOG ratings ONLY apply to passenger tires, even LT tires dance to a different tune.

trailer, utility, motor cycle, atv, wheelchair tires and so on aren't required to COMPLY with or USE those standards...

that alone may fuel much of the "st tires are inferior" thinking....

true or not.

perhaps the most import notation is this...

"Unfortunately for all of the money spent to test, brand and label the tires sold in the United States,
the Uniform Tire Quality Grade Standards have not fully met their original goal of clearly informing consumers
about the capabilities of their tires. Maybe it's because tires are so complex and their uses can be so varied,
that the grades don't always reflect their actual performance in real world use."


cheers
2air'
__________________
all of the true things that i am about to tell you are shameless lies. l.b.j.

we are here on earth to fart around. don't let anybody tell you any different. k.v.
2airishuman is offline   Reply With Quote
Old 09-14-2008, 09:37 PM   #526
Moderator
 
jcanavera's Avatar

 
2004 30' Classic Slideout
Fenton , Missouri
Join Date: Mar 2002
Posts: 9,002
Images: 143
Send a message via AIM to jcanavera Send a message via Skype™ to jcanavera
Quote:
Originally Posted by 2airishuman View Post
yes they do.

and the speed rating system for passenger car tires,

has NO relationship to how ST tires are labeled, tested or rated.

cheers
2air'
Understand...but take a passenger tire and exceed the speed rating for a length of time and you stand a higher chance of tire failure. Exceeding ratings for a tire, no matter on how the tire standard is set does preclude the tire to have a shortened life. That may manifest itself in premature wear out, or in worse case a failure of the tire to maintain its structural integrity.

Bottom line you run an ST tire in excess of the 65 mph that is stamped on the rating at the max inflation pressure, you lose load rating capacity...that's a fact. Dependent upon how much capacity is lost as you exceed 65 mph, and the actual load that the tire is carrying, the potential looms for an overload situation which we can all agree is a tire killer.

Jack
__________________
Jack Canavera
STL Mo.
AIR #56
'04 Classic 30' S.O.,'03 GMC Savana 2500,'14 Honda CTX 700
jcanavera is offline   Reply With Quote
Old 09-14-2008, 09:38 PM   #527
Rivet Master
 
SteveH's Avatar
 
2005 39' Land Yacht 390 XL 396
Common Sense , Texas
Join Date: Sep 2007
Posts: 5,311
Found this on the Discount Tire site about trailer tires

THE RIGHT TIRES
When purchasing or replacing trailer tires, look for the ST (Special Trailer) designation. Avoid using a passenger car (P) tire or light truck (LT) tires, as these do not have stiff, beefy sidewalls and other structural components to provide stability and handle the stress and dynamics imposed by a trailered load.

Modern ST tires feature materials and construction to meet the higher load requirements and unique demands of trailering.
"The major difference is reflected in the polyester cords used in ST tires," said Tim Fry, senior development engineer with Goodyear Tire & Rubber Co. in Akron, Ohio. "These cords are bigger than they would be for a comparable P or LT tire. Typically, the steel wire also has a larger diameter or a greater tensile strength to meet the additional load requirements.
"Because of the heavier construction for an equal volume of air space, an ST tire is designed to carry more load (than a P or LT)," says Fry.
What's more, the ratings on ST tires are standardized for axle ratings on trailers, according to Leo Garbarino, regional sales director for Carlisle Tire and Wheel Co. of Aiken, South Carolina. "If you have a 5000-pound axle, use an ST tire rated at 2540 pounds, so that two tires will meet the 5000 pound requirement in weight-carrying capacity," said Garbarino. "A P or LT tire is not rated the same way, so determining the load capacity can be difficult."
If the combined tire ratings do not meet the axle ratings, the tires will eventually fail-perhaps in a catastrophic blowout.
Bias ply trailer tires normally have two belts of steel in the tread area and extra sidewall cords to add stiffness. Most tires also include nylon belts to help resist separation caused by overloading, underinflation or excessive speed.

FAILURE ANALYSIS
Even properly rated tires can fail. The No. 1 cause is underinflation. This is particularly true of an ST tire, which relies on proper inflation to live up to its load rating. Without enough air pressure, an ST sidewall will not function as designed, and will eventually fail, usually in the form of a sidewall blowout. Tires lose approximately 1 psi per month as well as 1 psi for every 10-degree drop in temperature.

Overinflation is also hard on a tire, causing irregular wear and possibly a blowout. Yet, you can't always spot improper inflation with a visual inspection, so check your tires frequently with an accurate air-pressure gauge.
Long-term fatigue can also weaken a trailer tire. There are a number of factors that accelerate fatigue, but heat buildup from towing at high speeds is one of the main culprits, according to Fry.
"If you trailer nonstop from Phoenix, Arizona, to Las Vegas, in 100-degree temperatures at 65 mph, you use up much of the resources of that tire, and you don't realize it," said Fry.
Fry is not talking about wearing out the tread. It is the tire's construction that is breaking down. As heat builds up, the tire's structure starts to disintegrate and weaken. Over the course of several trips, this load-carrying capacity gradually decreases, according to Fry. Incidentally, all ST tires have a maximum speed rating of 65 mph.
One key to extending tire life on a tandem- or tri-axle trailer is to ensure that the trailer is riding level, thus distributing the load equally among all the tires. If the trailer tongue sits too high, the rear tires may bear the brunt of the load: with the trailer tongue too low, the front tires may be unduly stressed.

OLD MAN TIME
Time and the elements can also weaken a tire. The structural components and bonding agents slowly break down. This is due primarily to internal air pressure forcing oxidation of the tire materials. Ultraviolet rays also attack the rubber on a tire left exposed to the sun. As a result, a 15-year-old tire that was rarely used may look virtually new, but because of the ravages of time and elements, it does not have the same strength as when it was new, according to Fry.

"As an estimate, in about three years roughly one-third of a tire's strength is gone, just because of the normal process of aging," Fry claimed. "We believe three to five years is the projected life of normal trailer tires."
__________________
Regards,
Steve
SteveH is offline   Reply With Quote
Old 09-14-2008, 11:12 PM   #528
Rivet Master
Commercial Member
 
lewster's Avatar
 
Vintage Kin Owner
Naples, FL , Hood River, OR
Join Date: Dec 2005
Posts: 7,279
Thanks Steve!

Nice find! But I have to disagree with what I've seen in the 'real world'. I have lots of clients that tow very large triple axel car carrying trailers behind their $Million motor homes. They often ask me to air up the rig and trailer before they leave FL in the Spring. I always look at the tires, and I have found most, if not all of these trailer tires to be LT rated!!!! So much for Mr. Goodyear! Also, ever seen an ST tire on a semi trailer???? Talk about weight, heat and speed......... I have nothing against ST rated tires when properly used within their design parameters....those parameters just don't work for me.

I changed my 15" ST Marathons on my single axel 19CCD to 16" 227/75-16 LT tires (the same tires that I have on my Sprinter) soon after I bought the trailer. I drive the Sprinter fully loaded all the time and don't tow my Airstream at 65MPH and regularly tow in the desert heat, so I feel that the choice of LTs was proper in my case. I'm currently on my 3rd set of LT tires in the Sprinter without a single issue (112,000 miles), and expect the same great service from the LTs on the Bambi (and my tandem axel work trailer that also has LTs on it).

YMMV......and probably will!!!!
__________________
Lew Farber...ABYC Certified Master Marine Electrician...RVIA Certified Master Tech ...AM Solar Authorized Installation Center...AIRSTREAM Solar & Electrical Specialist...Micro Air 'Easy Start' Sales and Installations
lewster is offline   Reply With Quote
Old 09-15-2008, 12:23 AM   #529
_
 
. , .
Join Date: Dec 2004
Posts: 8,812
Quote:
Originally Posted by jcanavera View Post
... take a passenger tire and exceed the speed rating for a length of time and you stand a higher chance of tire failure...
well as i understand it just 10-15 minutes time running at or above the speed ratings results in tire failure, they just come apart.

they are rated to 'just short' of the failure point.

since many of us run long hours and 1000s of miles above 65 mph on the gyms, it obvious the rating system is DIFFERENT.


Quote:
Originally Posted by jcanavera View Post
...Bottom line you run an ST tire in excess of the 65 mph that is stamped on the rating at the max inflation pressure, you lose load rating capacity...that's a fact...
i see it repeat often HERE but without support from any official tire maker documents...

gotta link to this somewhere?

the goodyear info on towing between 65 and 75 mph covers inflation and load issues,

but makes NO mention of 'losing' capacity other than in loads vs underinflation situations.

and i agree with lew that LT tires can work and have been proven over time on MANY trailers...

check out the big 5th wheels, race car teams and so on...

almost ALL of them on rolling above LT tires, but for how many years will the trailer last?

on triple axles streams clearance is an issue (but still doable) however i've read the NEW panamerican toy hauler has 16/LT rubber.

cheers
2air'
__________________
all of the true things that i am about to tell you are shameless lies. l.b.j.

we are here on earth to fart around. don't let anybody tell you any different. k.v.
2airishuman is offline   Reply With Quote
Old 09-15-2008, 06:41 AM   #530
Rivet Master
 
SteveH's Avatar
 
2005 39' Land Yacht 390 XL 396
Common Sense , Texas
Join Date: Sep 2007
Posts: 5,311
Ratings....

I think the speed "Ratings" must be on the conservative side. Don't think the tire manufacturers want to keep ALL the lawyers busy.

I know for a fact on our trip of 11,000+ miles this summer to Alaska and back, a great deal of the trip where possible (read on American Interstates) was done at 70-75 MPH, and we had no tire problems on our 23' Airstream. And, one of those tires had been repaired with a plug!

It was one of those punctures too close to the side of the tread for a patch to hold.

Anyway, I know for a fact these trailer tires will not immediately self distruct if driven over 65 MPH.
__________________
Regards,
Steve
SteveH is offline   Reply With Quote
Old 09-15-2008, 07:33 AM   #531
Aluminut
 
Silvertwinkie's Avatar
 
2004 25' Safari
. , Illinois
Join Date: Feb 2003
Posts: 10,334
Though I don't advocate driving 75+mph towing, the posted speed limits on some interstates can be around 75mph. Shouldn't tires be rated for at least the maximum posted speed limits the tires could see? I realize that we live in the global economy and that it's a fool's paradise out there, but it just seems to me that unless you are doing something a-typical, that tires should have enough of what is needed to do at least the posted speed limits around the country.

Me, I stick to about 62mph fairly regularly. Sure I've passed at 75 once in a while, but never for extended periods of time. But let's face it, we all know the sweet spots our rigs get the best MPG....few, if any have I ever heard get the best fuel econ at 75mph. Of course if money is no object, 9 mpg can be a small price to pay to get to your destination a bit earlier.

For me, I can get about 12 mpg if I stick to 62 mph....slower, near 55 mph, I can get upward of 13 to 14.

Now don't get me wrong, I love speed like the next guy and love to get where I'm going.... when I'm not towing and driving my 1996 modified Impala SS, I can assure you with my Z rated nylon capped steam roller type tires, I go significantly above the posted speed limit. Funny thing is that I just got a "safe driver" renewal certificate from the state saying I wouldn't have to come in to renew my license.
__________________
Computers manufactured by companies such as IBM, Compaq and millions of others are by far the most popular with about 70 million machines in use worldwide. Macintosh fans note that cockroaches are far more numerous than humans and that numbers alone do not denote a higher life form. -NY Times 11/91
Silvertwinkie is offline   Reply With Quote
Old 09-15-2008, 01:27 PM   #532
_
 
. , .
Join Date: Dec 2004
Posts: 8,812
Quote:
Originally Posted by SteveH View Post
...It was one of those punctures too close to the side of the tread for a patch to hold.

Anyway, I know for a fact these trailer tires will not immediately self distruct if driven over 65 MPH.
which is exactly why i suggest the rating methods are different, and don't apply as they do with p tires.

on the patch/plug issue, my understanding is that punctures near the belt edges are not to be repaired using ANY method.

the 'no repair' zone is about 5/8-3/4 inches in from tread margins...

having experienced 3-4 nails/screws and foreign objects imbedded in tires this year,

i'll soon put up pics of each and how they were handled.

cheers
2air'
__________________

__________________
all of the true things that i am about to tell you are shameless lies. l.b.j.

we are here on earth to fart around. don't let anybody tell you any different. k.v.
2airishuman 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
Goodyear G670 RV Tires??? TRAPEZE Airstream Motorhome Forums 16 11-27-2006 04:19 PM
Goodyear Marathon "C" out of production Wabbiteer Tires 13 07-18-2006 05:24 PM
Goodyear Marathon Source Jabba Tires 28 02-22-2004 12:16 PM
Goodyear G670 RV Tires??? TRAPEZE Tires 2 07-08-2002 06:38 PM
Goodyear tires available at Camping World 83Excella Tires 0 05-09-2002 09:29 AM


Virginia Campgrounds

Reviews provided by




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 07:00 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.