Reply
 
Thread Tools Search this Thread Display Modes
 
Old 07-26-2013, 06:28 AM   #41
Rivet Master
 
switz's Avatar

 
2014 31' Classic
2015 23' International
2013 25' FB International
Apache Junction , Arizona
Join Date: Sep 2012
Posts: 5,426
Images: 8
All these tire reservations sound great on the the small to midsize trailers. But the larger units only have two axles today instead of three. Those new models are the 31' Flying Cloud and International with a 8,800 pound GVW and all the Classic models which have a higher GVW starting at 9,000 to 10,000 pounds.

So doing the math recommended by CapriRacer with Michelin LT 225/75R16E tires that are rated 2,680 pounds at 80psi, we find the initial weight capacity reduced to 2,278 pounds. Then, after only getting the twin axle weights together, we have to deduct another 15% to 1,936 pounds or 7,744 pounds for four tires.

Using this analysis, four Load E tires at maximum inflation would not have the load capacity for any of the trailers mentioned above with a load or the longer Classics empty. They would also lack the load capacity for the 19' Bambi with a single axle and a 4,400 pound GVW. Certainly, the factory supplied GYM ST225/75R15D tires would be overloaded even before loading the trailer since their capacity per this formula is only 1,835 pounds or 7,340 pounds for four tires. Per these calculations, the GYM tires should only be used on the tandem axle trailers with 7,300 pound GVW or less.

At this point, I do not see 17" Load E tires fitting in any existing Airstream wheel well. The Michelin LT245/75R17E is rated 3,195 pounds and is 31.5" in diameter or 3.2" larger diameter than the GYM ST tires. However, their derated capacity per the above suggestions would be 2,308 pounds or 9,233 pounds for four which would carry the two longer Classics axles as well as the 19' Bambi single axle.

These number follow the suggested formula. Not everyone has access to a CAT scale or a grain elevator scale. Of course one could spend close to $5,000 and have their own set of five wheel pad scales to verify the weights before each trip.

Federal law requires each new vehicle be weighed as it comes off the line. Adding a few words to the law could make sense. "the weight per wheel and it's location on the unit" must be disclosed on the door label.

Airstream, for whatever reason, supplies four GYM ST225/75R15D tires on the tandem axle trailers (or two on the single axle trailers) plus one as a spare. They have to be responsible that the tire will do the job or there would be a huge liability exposure.

My purchase of four Michelin LT 225/75R16E tires exceeds the weight capacity of the GYM tires and has no maximum speed restrictions and they fit on the trailer. I will have a current tire design with a greater safety margin in terms of load capacity and there seems to be NO chronic reporting of tire failures for Michelin.

Regardless of tire choice, I still must use common sense when loading the trailer, it is not a moving van.
__________________

__________________
WBCCI Life Member 5123, AIR 70341, 4CU, WD9EMC

TV - 2012 Dodge 2500 4x4 Cummins HO, automatic, Centramatics, Kelderman level ride airbag suspension, bed shell

2014 31' Classic model 30 twin beds, 50 amp service, 900 watt solar system, Centramatics, Dill TPMS, disc brakes, 16" tires & wheels
switz is offline   Reply With Quote
Old 07-26-2013, 09:15 AM   #42
Master of Universe
 
Gene's Avatar
 
2008 25' Safari FB SE
Grand Junction , Colorado
Join Date: Sep 2007
Posts: 11,428
[QUOTE=switz;1331836]
Airstream, for whatever reason, supplies four GYM ST225/75R15D tires on the tandem axle trailers (or two on the single axle trailers) plus one as a spare. They have to be responsible that the tire will do the job or there would be a huge liability exposure.

/QUOTE]

That's assuming Airstream knows what it is doing. They have a tendency to do what they've always done and find out later they screwed up. I doubt they go through the painstaking analysis that goes on here.

Gene
__________________

__________________
Gene

The Airstream is sold; a 2016 Nash 24M replaced it.
Gene is offline   Reply With Quote
Old 07-27-2013, 07:13 AM   #43
Rivet Master
 
switz's Avatar

 
2014 31' Classic
2015 23' International
2013 25' FB International
Apache Junction , Arizona
Join Date: Sep 2012
Posts: 5,426
Images: 8
One could wonder if Airstreams use of the GYM ST225/75R15D is another way to generate ancillary sales of parts and repair service due to tire failure.

It seems that eveything today in the corporate culture is a sub-profit center. Even shipping charges that are twice or three times the value of the stamp on the envelope or package generate a small profit.
__________________
WBCCI Life Member 5123, AIR 70341, 4CU, WD9EMC

TV - 2012 Dodge 2500 4x4 Cummins HO, automatic, Centramatics, Kelderman level ride airbag suspension, bed shell

2014 31' Classic model 30 twin beds, 50 amp service, 900 watt solar system, Centramatics, Dill TPMS, disc brakes, 16" tires & wheels
switz is offline   Reply With Quote
Old 07-27-2013, 07:24 AM   #44
Rivet Master
 
Currently Looking...
K.C. , Missouri
Join Date: Nov 2011
Posts: 585
Quote:
Originally Posted by switz View Post

Airstream, for whatever reason, supplies four GYM ST225/75R15D tires on the tandem axle trailers (or two on the single axle trailers) plus one as a spare. They have to be responsible that the tire will do the job or there would be a huge liability exposure.

.
If the load capacity of the tires they mount are equal to or exceed the axle capacity, and if the GVWR of the trailer is within what the sum of the axle capacities and the tongue weight, then Airstream has met the requirements, I would think.
If the tires fail, I would guess the majority of the burden lies with the tire manufacturer, as it is they who tell Airstream that their product meets the desired specs for use.

From a corporate level, at least some of this is about risk management, and they ( GoodYear and Airstream ) know there are going to be "some failures" in the field. Some of these failures may be user error ( overloaded, underinflated, overspeed ) and some may be due to manufacturer defect. It's why the tire company has a warranty, etc.

What amazes me about the whole thing is why many folks defend the whole ST tire scenario. Why should we accept a product that limits us to 65 mph and has to be replaced on age alone in three to five years when we can instead use a tire ( LT in this case ) that has a 100 mph limit, giving us a potentially larger margin of safe operating envelope, and which has a ten year lifespan ( according to Michelin ).
I'm just not seeing why I should have any love for a ST.

With all due respect to the poster who commented, I suspect Airstream
has thought long and hard about all of this, as evidenced by the fact they fit Michelin LT to some of their trailers as OE and make it optional on others. Sounds to me like it's simply about dollars....as in more dollars of profit for them if they can get a consumer to accept ST at the normal selling price of the trailer. And then when you do option the bigger wheels and LT tires, even more profit, as they are essentially double charging you for wheels and tires, as the option price is nearly what it would cost you to go out and buy the 16" upgrade after you get the trailer home.
gmw photos is offline   Reply With Quote
Old 07-28-2013, 05:59 AM   #45
Rivet Master
 
switz's Avatar

 
2014 31' Classic
2015 23' International
2013 25' FB International
Apache Junction , Arizona
Join Date: Sep 2012
Posts: 5,426
Images: 8
That comment about Airstream double charging for better tires is correct. I have ordered a 2014 27FB Classic to be built in January with only the options we want. I asked about having the 16" Michelin tires and 16" SenDel wheels installed while the unit is being built. After all, the Eddie Bauer model can be built with these tires so they are in the building.

They mount the 15" tires and wheels on the trailer and then apparently charge for the installation and the 16" tires and wheels with no credit for the 15" that would typically come off and stay in their inventory. Also, while Airstream makes a profit on this option sale, if it comes from from the factory, the dealership gets a piece of the pie as well.

I elected to source the 16" Michelin tires and SenDel wheels locally, have Costco mount the 5 tires on the new wheels and personally take them to the trailer and install them myself along with a set of Centramatics (perhaps even install them on the dealership lot). I will then sell the 15" GYM ST tires along with the 15" factory rims and recover some of the costs of the upgrade.

I am also looking into the Dill TPMS system, but on their web site they only have two valve stem diameters (0.453"and 0.625") and the SenDel wheels have a 17mm (0.699") valve stem hole for a T-14-R valve stem.
__________________
WBCCI Life Member 5123, AIR 70341, 4CU, WD9EMC

TV - 2012 Dodge 2500 4x4 Cummins HO, automatic, Centramatics, Kelderman level ride airbag suspension, bed shell

2014 31' Classic model 30 twin beds, 50 amp service, 900 watt solar system, Centramatics, Dill TPMS, disc brakes, 16" tires & wheels
switz is offline   Reply With Quote
Old 07-28-2013, 06:21 AM   #46
Slide Out Society #001
 
GCinSC2's Avatar
 
2007 30' Classic S/O
Somewhere , South Carolina
Join Date: Apr 2010
Posts: 3,112
Quote:
Originally Posted by switz View Post
I am also looking into the Dill TPMS system, but on their web site they only have two valve stem diameters (0.453"and 0.625") and the SenDel wheels have a 17mm (0.699") valve stem hole for a T-14-R valve stem.
switz,

Interesting observation .699" stem. Certainly merits contacting Dill if you haven't. I contacted them when I researched my purchase. Got info straight from someone willing to listen and offer answers.

I think 16's are my next project.

One thing I have done while the trailer is waiting for the next outing, I have a pair of 1 ton p/u screw jacks and have taken some weight off of the axles and tires.

Gary
__________________
S/OS #001
2005 Dodge Ram 2500 5.9L 6 Speed
16" Michelins, Hi Spec Wheels, Max Brake, Carslile Actuator, Equal-i-zer, Dill TPMS. Campfire cook.
GCinSC2 is offline   Reply With Quote
Old 07-31-2013, 06:08 AM   #47
Vintage Kin
 
slowmover's Avatar
 
Fort Worth , Texas
Join Date: Nov 2006
Posts: 8,009
Images: 1
One thing I have done while the trailer is waiting for the next outing, I have a pair of 1 ton p/u screw jacks and have taken some weight off of the axles and tires.


Have a look at the way ROBERT CROSS stores his TT for winter.
__________________

__________________
1990 35' Silver Streak Sterling; 9k GVWR.
2004 DODGE Cummins 305/555; 6-manual; 9k GVWR.
Hensley Arrow. 12-cpm solo, 19-cpm towing (fuel)
Sold: Silver Streak Model 3411
slowmover 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



Featured Campgrounds

Reviews provided by

Disclaimer:

This website is not affiliated with or endorsed by the Airstream, Inc. or any of its affiliates. Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 04:55 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
×