Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×
 

Go Back   Keystone RV Forums > Keystone Fleet | Keystone RV Models > Fifth Wheels
Click Here to Login

Reply
 
Thread Tools Display Modes
 
Old 10-04-2020, 08:43 AM   #21
Tireman9
Senior Member
 
Join Date: Sep 2018
Location: Akron
Posts: 453
Quote:
Originally Posted by flybouy View Post
If it's a DOT mandate then I'd think it would have to done by a DOT approved lab.

Nope. DOT does not test tires in that manner.
When a tire company puts the "DOT" symbol the tire company is certifying that the tire, when new, is capable of meeting and passing all appropriate standards.


Each company uses it's own QA standards to establish their own performance minimums and test sampling frequency for their tires. In my experience each tire plant is testing tires continuously but since test equipment is expensive as is testing itself they test on a sampling basis.


Sampling is done on a statistical basis by each plant.


Michelin and Goodyear in their RV tire data book show 75 mph max speed for their tires when used in RV application. Goodyear has an exception with their ST type tires where they claim higher speed is allowable. Michelin and Bridgestone do not make ST type tires.


Based on my visual examination of GY Endurance and Marathon tires i believe the Endurance has features which should deliver improved durability. However I do not understand how they managed to make tires that perform at similar speed to LT type tires yet have significantly higher load capacity. It's almost magic.
__________________
Retired Tire Design Engineer (40 years). Serve on FMCA Tech Advisory Committee. Write a blog RV Tire Safety. Read THIS post on Why Tires Fail.
Tireman9 is offline   Reply With Quote
Old 10-04-2020, 08:47 AM   #22
Tireman9
Senior Member
 
Join Date: Sep 2018
Location: Akron
Posts: 453
Quote:
Originally Posted by DBinSD View Post
PLEASE PLEASE PLEASE pay attention to the SPEED RATING of these ST tires on your units!
Most of them have E or G SPEED RATING. That is 45 or 56 MPH MAXIMUM ! If you drive faster than that you will need a better rated tire.

We are changing our new trailer tires to Goodyear Endurance 255/85R16 Load E (4080 lb) with a Speed rating on N (87MPH) as we usually cruise about 70MPH.

Speed is causing the majority of blow outs, not the tires themselves.

Good luck, happy travels !

Interesting. I do not recall ever seeing ST type tires with E or G speed rating. Can you provide any pictures of the sidewall markings showing those speed symbols?
__________________
Retired Tire Design Engineer (40 years). Serve on FMCA Tech Advisory Committee. Write a blog RV Tire Safety. Read THIS post on Why Tires Fail.
Tireman9 is offline   Reply With Quote
Old 10-04-2020, 09:40 AM   #23
flybouy
Site Team
 
Join Date: Oct 2011
Location: Joppa, MD
Posts: 11,709
Quote:
Originally Posted by Tireman9 View Post
Nope. DOT does not test tires in that manner.
When a tire company puts the "DOT" symbol the tire company is certifying that the tire, when new, is capable of meeting and passing all appropriate standards.


Each company uses it's own QA standards to establish their own performance minimums and test sampling frequency for their tires. In my experience each tire plant is testing tires continuously but since test equipment is expensive as is testing itself they test on a sampling basis.


Sampling is done on a statistical basis by each plant.


Michelin and Goodyear in their RV tire data book show 75 mph max speed for their tires when used in RV application. Goodyear has an exception with their ST type tires where they claim higher speed is allowable. Michelin and Bridgestone do not make ST type tires.


Based on my visual examination of GY Endurance and Marathon tires i believe the Endurance has features which should deliver improved durability. However I do not understand how they managed to make tires that perform at similar speed to LT type tires yet have significantly higher load capacity. It's almost magic.
I didn't say the DOT did the test. I said I'd think they would be fine in a DOT approved lab. But I guess if that is true (the I'd think part is admission of that not being fact), then I'd think that would be the tire company "proclaiming" to be in compliance. As I am not a "self proclaimed" tire expert I wouldn't know.
__________________
Marshall
2012 Laredo 303 TG
2010 F250 LT Super Cab, long bed, 4X4, 6.4 Turbo Diesel
flybouy is offline   Reply With Quote
Old 10-04-2020, 10:54 AM   #24
jadatis
Senior Member
 
Join Date: May 2013
Location: Holland ( Europe)
Posts: 178
When ST on sidewall, regardles if the speedcode or maximum speed given, the maximum load is calculated for 65mph.
Even the Endurance with its N speedrating( max speed 140kph/87mph)
If you compare the old Goodyear ST pressure/ loadcapacity lists with the new Endurance list, you see that Endurance is yust an extension of the old lists. To my conclusions that proves the same speed for wich maxload is calculated.

Hope I placed the right inflation table pdf.
Attached Thumbnails
Click image for larger version

Name:	STtiresdangerousPLClist.PNG
Views:	82
Size:	76.2 KB
ID:	30138   Click image for larger version

Name:	Screenshot_20201004-233626_Adobe Acrobat.jpg
Views:	74
Size:	153.5 KB
ID:	30152  
jadatis is offline   Reply With Quote
Old 10-04-2020, 12:32 PM   #25
Ribtip
Senior Member
 
Ribtip's Avatar
 
Join Date: Mar 2020
Location: Braidwood
Posts: 218
In my experience i have had good luck with carlisle and maxxis tires both on my trailers five'r and boat. The trailer kings that came on five'r were crap.
Ribtip is offline   Reply With Quote
Old 10-05-2020, 07:46 AM   #26
CWtheMan
Senior Member
 
CWtheMan's Avatar
 
Join Date: Feb 2010
Location: Taylors, SC
Posts: 3,031
Quote:
Originally Posted by CWtheMan View Post
The same way as almost all others, by 3rd party.

Has it got DOT on the sidewall? For it to get there someone in an official capacity said it was tested.
Sometimes Tireman9 does not tell the whole story. (Remember, he is a commercial poster and his blog is sponsored). I'm adding a short sentence to better elaborate.

Once a tire has been constructed, it's put through an exhaustive series of tests. These tests are performed at tire test centers. Tire test centers may be owned and operated by the tire manufacturer, third parties, or government entities.

Speed testing is an internal function of the tire manufacturer. The only information they are required to produce is an official assurance letter to DOT certifying a test for the tire sidewall speed letter has been successfully completed by any one of the agencies described above. Regardless of what the TRA says, the DOT seal is finite. If not, the only recourse is RECALL.
CWtheMan is offline   Reply With Quote
Reply

Tags
cougar

Thread Tools
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
Forum Jump

» Featured Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3
Disclaimer:

This website is not affiliated with or endorsed by the Keystone RV Company or any of its affiliates in any way. Keystone RV® is a registered trademark of the Keystone RV Company.


All times are GMT -8. The time now is 04:33 AM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2024, vBulletin Solutions, Inc.