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Monday, July 15, 2024

What inflation should I run in my tires?

After I published information on what "MAX" means on a number of RV Forums, I had a few folks thank me for the clarification. But they followed up by asking where to find the Inflation Tables. This request surprised me as I thought that most people knew that they can check my RVTireSafety net blog or simply "Google" about almost any topic if they had a question but I apparently was wrong. 

So here is a collection of links to the various tables published by different tire companies. Since not all tire companies make all sizes you may need to check the table for a different tire company if you can't find the info for your particular tire.

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.

If you find an error or omission in this list, please drop me an email 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.

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

Tuesday, July 9, 2024

Improper trailer brake setting

Just a quick post with the "Evidence" you might need to confirm improper brake force setting on a trailer.

This is definitely "Brake Flatspotting" from trailer tire lock-up. Higher force on relatively light loaded tires can cause this. Once there is a spot the next time you hit the brakes the tire is more likely to stop at the same spot again.

Here are some examples removed from passenger cars. ( note your ST type and LT type tires will look similar)

It might be a good idea to check your brake settings every couple thousand miles such as when you re-pack your wheel bearings.

 Did you take a close look at the tread surface when you did your last 2,000-mile tire "Free Spin" inspection or when you re-packed your wheel bearings on your trailer?