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Thursday, April 23, 2015

The Use Of Internal Balancing Materials and/or Coolants In MICHELIN® Truck Tires

I hope this answers the questions some have about the use of alternate materials for tire balancing.

The Use Of Internal Balancing Materials and/or Coolants In MICHELIN® Truck Tires

The use of internal balancing materials and/or coolants (such as powders, liquids, gels and/or beads) in MICHELIN® Truck Tires does not automatically affect the tire warranty unless the internal balancing material and/or coolant has a high water/moisture content or that it is determined that the internal balancing material and/or coolant has adversely affected the inner liner, casing plies, or the performance of the tires.

Prior to using any type of internal balancing material and/or coolant, Michelin strongly recommends that the customer make sure the internal balancing material and/or coolant has been tested and certified by the internal balancing material and/or coolant manufacturer as being safe for use in tires. Water/moisture content testing should be included in the certification process. Any product with a water or moisture content greater than 3% as measured by the Karl Fisher Method (ASTM D6304) will automatically void any mileage, number of retreads and/or time warranty.

In addition to the forgoing, please refer to the Michelin Truck Tire Operator’s Manual and Limited Warranty (MWE40021) for a general discussion of what is and is not covered by the warranty.

NOTE: Please consult Michelin prior to using internal balancing materials and/or coolants in any MICHELIN® tires that have sensors in them. The internal balancing materials and/or coolants may adversely affect the performance of the sensors.

For additional information, please contact your local Michelin sales representative or contact Michelin using the website at

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Tuesday, April 21, 2015

Links to Load Inflation tables

Last updated Sep 11 2022

Almost all tire companies follow similar load formula calculations in the USA, Europe and Asia. BUT minor differences occasionally occur due to doing calculations in inches and pounds vs millimeters and kilograms as there is rounding that takes place along with some minor differences in some "K" factors. Also some sizes have been around for decades so their load capacities may not match the formulas exactly but are just accepted as acceptably close. So there are minor variations. This is why it is best to use the tables published by the company that makes your brand of tire.

Sometimes this is easy because you use one of the big name companies such as Goodyear or Michelin while other times you may find you have tires that are not actually made by the company with the name on the sidewall but are in fact just imports made in common molds with changeable nameplates.

This post will be updated when I learn about a company posting load inflation tables for their line of tires.  If you find an error or omission, please drop me an email (address under my picture on the right) with the link that needs correcting or new link and I will update this post. That way you can bookmark this page and save it for future use.

I plan on listing the links base of alphabetical list of the tire company name.
To the best of my knowledge Both Goodyear and Bridgestone/Firestone follow the Tire & Rim Association (US) published tables so you can simply look at their tables for the numbers if you can't find your tires in any of the links below.

If you find a broken or bad link please send me an email so I can fix it. Thanks.

Links to Load Inflation charts, How to Weigh your RV worksheet and related material. Note Bridgestone "Medium and Light Truck data Book includes Load inflation tables for 16" and larger tires for both Bridgestone and Firestone brand tires.

Carslile  Has product info and size list but no Load Inflation tables However since they only have ST type tires which I suggest always be run at the inflation pressure molded on the tire you can use the max load info to confirm you are running under the tire max by at least 15% for longer tire life while still maintaining the tire max inflation. They do have three larger size ST type tires found HERE

Databook for commercial tires 

Cooper  Does not publish Load & Inflation tables. I suggest you use Bridgestone or Goodyear tables

Double Coin truck tire
Load & inflation for 19.5" and larger

General truck tires
Load Inflation tables

RV tire information including link to Load & Inflation tables

Hankook Medium-duty Truck tire info. The link will download their catalog with Load & Inflation info.

Hercules  Does not publish Load & Inflation tables. I suggest you use Bridgestone or Goodyear tables. BUT their high load ST tire info can be found HERE

Product info page and links to their technical information.
Note they show both P-metric and "Euro-metric tires that do not have a P prefix but based on the inflation these are basically passenger type tires even though some are listed under "Light Truck". Only their "Road Venture has actual LT type tires listed.  They do have 19.5 and 22.5 size tires.

Tire data on LT tires but no Load Inflation tables. I suggest you use Bridgestone or Goodyear tables

MAXXIS Trailer tires
Tire data on ST tires but no Load Inflation tables. I suggest you use Goodyear tables

MAXXIS Trailer Load & Inflation tables

RV Tire guide and links to Reference Materials and Load Inflation tables for 16" to 24.5" tires in RV application. NOTE many of the Michelin tables are not based on single tire loads but axle loads so you will need to divide the Michelin numbers by 2 for Fronts and by 4 for dual position individual tire loading. This just adds a bit of confusion to your calculations. I also am aware that a number of Michelin tires do not follow the US TRA tables so if you are using Michelin brand you really do need to use their tables.  16" and other size Load Inflation tables can be found HERE

This importer is offering 75 mph speed rating on these ST type tires.

Sailun   S637  17.5 size Tire information  Load & Inflation tables.  Here is info for their ST637T   ST type tire

Sumitomo you can download their booklet on Medium Truck size tires for 19.5 & 22.5 sizes
Load Inflation table on pg 4

Towmax  does not publish tables only the tire max load.

RV tire care and Load & Inflation tables. Also a good overview of info on tires including Passenger tires.  Truck size (22.5) info can be found HERE

 Trailer King has tire spec sheet shat show the max load and required inflation HERE.


Uniroyal LT size info. They say to use the Michelin Load & Inflation tables. "It's important that you get all the safety-related materials that come with the purchase of new Uniroyal passenger and light truck tires. If you did not receive a warranty book, you can download one at If you did not register your tires, please take a moment to do so at Registering your tires is easy and takes just a minute."

Info on their commercial tires on pg 23 HERE.

 Others will be added when the tire company responds to my request for a link, or when someone lets me know about a link.

NOTE If you can't find your specific tire size load & infl info from your mfg you should call their Customer Service number.  I also note that the Toyo technical guide has LOTS of useful information.

General information

How to read a tire Load Inflation table
Barry's Tire Tech

National Highway Traffic Safety Administration
Tire Safety

File a complaint about a tire failure with NHTSA

Air Pressure, Temperature variation
Tire Rack      
or go HERE

Passenger tire inflation w/video

The Tire & Rim Association. Where to buy Industry Standards books

MasterCraft tire Education

Rubber Manufacturers Association
Links to Tire Safety information

RV Safety Education Foundation
RV education and tire weighing service

Truck Scales

CAT Scales
Truck Scales

General information and weight calculations for trailer owners

Please send me an email Tireman9   at   if you find one of these links is broken. Thanks

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##RVT803 (updated 7/2017)

Wednesday, April 15, 2015

NEW DOT serial info but date code portion to stay the same

NHTSA Standardizes Tire Identification Number

Change Accomodates Increasing Number of Global Tire Plants

WASHINGTON, DC, April 14, 2015 – The National Highway Traffic Safety Administration (NHTSA) announced a final rule to standardize the Tire Identification Number (TIN) imprinted on tires sold in the U.S.  The new regulation creates a 13 digit TIN for new tires and seven digit TIN for retreaded truck tires.

NHTSA initiated the rulemaking because it had exhausted the number of two-digit plant codes the agency issues to every tire plant making tires for the U.S. market.  The new TIN will have a three-digit plant code.

The Rubber Manufacturers Association commented to NHTSA when its membership voiced concerns over some aspects of the proposed rule.

“RMA appreciates NHTSA’s effort to create an effective regulation to continue its obligation to provide plant codes to manufacturers while making common-sense accommodations to limit unnecessary costs,” said Dan Zielinski, RMA senior vice president, public affairs.

RMA commented on the proposed rule urging NHTSA to drop a proposed requirement for a 50 mm blank space after the TIN. RMA argued the additional space would add significant cost to the rulemaking with no safety benefit while causing extensive remodeling to tire molds around the world. The final rule eliminated the proposed 50 mm requirement.  Additionally, RMA successfully argued that tire manufacturers be given 10 years to phase in the new rule’s requirements.  RMA noted to NHTSA that a majority of tire molds last as long as 10 years. NHTSA agreed with RMA.

“RMA agrees that NHTSA needs to change the TIN to a three-digit plant code,” said Zielinski.  “RMA members had several concerns with the proposal that would have needlessly raised costs to tires produced in the U.S. and NHTSA agreed to make key changes.”

In response to other stakeholder requests to change the date stamp portion of the TIN, NHTSA said, “…we do not believe a change to the date code is necessary for consumers to determine when their tires were manufactured.”  NHTSA added that sufficient information to understand the date stamp is available online or by asking a tire dealer.”

Click here to link to NHTSA rule.
# # # #
The Rubber Manufacturers Association is the national trade association for tire manufacturers that produce tires in the U.S.  All RMA press releases are available at

 I am confident that the info on the plant look-up web site
will be updated as new plant locations are added.

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Tuesday, April 14, 2015

Causation or Correlation Tires may be too good. Even "China Bombs"

The fundamental problem with the idea that just because the plant that built the tires is painted green, or has two floors rather than one, or has a Zip code beginning with 9 rather than 4, or is built by people that speak Spanish rather than German, etc., that we should expect that all tires made at one location to fail at a high frequency, is not based on sound problem analysis. I could just as easily claim that RV workers that live in Ohio are poor workers because over 95% of every RV problem reported on an Airstream RV forum was built by workers living in Zip code starting with 45.

Lets break this down:
It is a fact that of the 30,000 or so RVs that have been weighed with individual tire position scales, over half have one or more suspension component (tire, wheel or axle) in an overload condition. It is important to remember that tires are almost always the lowest rated item in the suspension. In any population of products, if over half are being used beyond their design intent (max load based on measured inflation) why would we be surprised if there is a relatively high failure rate? Maybe even as high as 1 or 2%.

Well, what if I said that 90% of the tires that are put on RV trailers are built in tire plants painted green? Does it seem logical that the color of the paint used on the building would result in a tire being weaker or to age faster? If that were true, maybe the color we paint the RV might have an effect on the life of your tires.

Let's also look at the design goals for many RV tires. Low cost is what the RV industry wants, so that is all the tire importer asks of the manufacturing plant. After all, they only give you a 12-month warranty -- if they give you any warranty at all. If you check around I think you will find that most major tire companies give you a 3- to 5-year warranty on their standard tires. Many even offer a road hazard warranty for a few bucks -- which means any failure for any reason is covered. Now, maybe if RV owners demanded, say, a 3-year warranty on the entire RV, including tires, or they won't buy the unit, then RV dealers would demand better quality from the RV assemblers, who in turn would specify better quality components. Such an improvement in quality would not result in a dramatic increase in price. It is even possible that the actual cost of ownership might be lower if the RV was built better to start with.

If you haven't studied Statistics, you might invest a few minutes and watch this video "Correlation does not mean Causation". You might see how improper analysis is many times used in advertising, on TV and even in political sound bites.

But back to tires.

Another fact is that other than with a complete loss of air, tires almost never fail as soon as they are overloaded or under-inflated or run faster than their designed speed. The reality is, in my opinion, that the problem with most tires produced today is that they are perhaps too good. Since they don't fail as soon as they are abused, the owner isn't immediately "punished" (by having an immediate tire failure), so the owner incorrectly assumes their actions are OK.

There have been documented cases of tires failing days and even weeks after being damaged from significant overload. A few cases have been well investigated as both personal injury and even deaths were involved.

This is both good and bad news. The good news is that tire failures happens infrequently. The bad news is that owners receive negative reinforcement that incorrect actions (over-load, low inflation and high speed) do not result in a failure, so the owner does not associate the failure with the incorrect behavior. Any parent knows that when a child does something wrong it does no good to chastise them days later. Now, I am not calling everyone that has had a tire failure a "bad" person or insinuating they are behaving like children. I am using this example as this is just basic psychology.

In a number of posts on failure analysis on this Blog, I have documented some tire failures that occurred and were not properly associated with the previous damage, so an incorrect conclusion was reached by the RV owner.

It is important to remember that if you do not properly identify the real reason for a product failure, simply changing the brand or painting your RV a different color will probably not prevent a recurrence of a future failure.

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Friday, April 3, 2015

How fast can I safely drive?

Recently saw a story on AP titled "Big rigs often go faster than tires can handle"

The basic point of the article was that over the past few years, states have increased highway speed limits from the 50 or 60 mph range to 75, 80 or higher but the tires in use are for the most part still rated for 75 mph and below.

I know I read many posts from RV owners stating they travel at speeds well above the max rating for their tires. Be that exceeding the 65 mph limit on ST type tires or exceeding the 75 mph rating whenever in RV service.

Some people incorrectly believe that since they drove faster than the tire speed capability last week and didn't have a problem they can drive that fast whenever they want. Nothing is further from the truth.

As I have pointed out in numerous posts both in this Blog and on various RV forums, tires can tolerate a certain level of abuse be it over-load, under inflation or over speed. But every minute a tire is operating outside its design capacity the driver is consuming large portions of the tire life and the tire will eventually fail. Sometimes in a catastrophic manner.
When that happens all to often the driver says "I was just driving 50 mph down the road and had checked the air that morning when the tire blew out. must have been a defective tire'. In reality it was the driver's conscious decision to ignore the specifications for the tire be it load, inflation or speed and many miles of improper operation finally caught up with the driver.

If you take a look at the Tire Selector link for Goodyear RV tire application and download the RV Tire Care Guide on pg 16 you clearly see the statement of 75mph max speed.

Checking Michelin web site we can see a similar 75 mph max as seen on THIS sample pg.

Firestone says 75mph as seen here.  and Bridgestone on their R250 says 75mph
and Toyo has a similar limit for truck/bus type tires.

The important thing to remember is that just like an engine Tachometer that has a "Red Line" engine rpm limit, it may be possible to exceed that limit for a short time but you will pay for that practice in shorter engine life or in the case of a tire shorter tire life.

Couple of comments. When using the above links you might need to do some additional searching as some web sites are portals to additional information.

Some tires such as LT type may have a higher speed rating than 75 but that would be for normal pick-up truck service and not for RV service which is different. Also ST type trailer tires have a lower speed limit of 65 mph and in some cased certain heavy duty trailer tires have even lower 62 mph limit.

I would strongly suggest you lower your actual normal travel speed to 5 mph lower than the tire limit and of course never exceed the posted limit or the limit that could be considered safe for the conditions.

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