Wednesday, September 27, 2023


RV Tire Safety: Could the information on your tire sidewalls be worth free tires?

By Roger Marble
I bet that few of you have ever bothered to read and record the important information provided on your tire sidewalls. There are a number of reasons for you to spend the few minutes it will take to do that. Having the facts might even be worth a free set of tires!

Here’s what you need from the tire sidewalls

1. Record the Department of Transportation serial number for each tire. They might all be the same or each tire could be unique. The complete 10- to 13-character code would be used if you have a failure and want to file a complaint with NHTSA.  This is the division of the U.S. DOT that is responsible for initiating recalls of vehicle components judged to not meet the DOT safety standards.

For tires, the DOT serial number is used to identify which tires are being recalled – and replaced for FREE. Without the serial number you have no way of knowing if your tires are subject to a recall or not.

It is definitely a lot easier to plan ahead and to collect the serial numbers on a sunny afternoon than on a rainy morning in the mud. You need to include all the letters and numbers, especially the last 4 numbers. Those are the “Serial Date Code.” That code identifies the week and year the tire was manufactured. Here is an example of an older 11-character serial number:

In this example the date code is 3908, which would correspond to the 39th week (October) of 2008. If you have a tire this old, I would strongly recommend you replace it ASAP. This is because it is well over the 10-year maximum age limit for any tire in RV application.

Why you might need to check both sides of the tire sidewall

When you start looking at your tires you may find something that looks similar but the last four characters are not numbers. You’ll need to inspect the other side of the tire because not all tires have the date code on both sides.

I suggest a flashlight and a 12-year-old, along with a $5 or $10 bill might be called for. It would be a long easier to hire some young helper to collect the date code from the other side of the tire. I know that I no longer find crawling around under my RV is easy on the knees as it once was.

Some of you will discover that you managed to park your RV so the date code is hidden by the frame or exhaust – so you may need to move the RV a couple feet. But don’t move the RV with the 12-year-old under the RV. Not Safe! (Roger says facetiously.)

Here’s a suggestion

When you buy new tires, get the dealer to give you the registration sheet that has the full DOT of every tire recorded. Same when you buy a new RV. It’s easier to get the dealer to crawl around to get the numbers.

OK, the DOT serial is the most important number to record and keep in an easy-to-find location. They should be stored along with the manuals for the furnace, stove, AC and other features of your RV.

2. A picture of your Certification Label aka Tire Placard would be a good idea to have on your computer or phone. The placard has a statement of complete tire size, load range and the GAWR plus the recommended inflation. Here is an example from an Airstream.

All of this information is important and should be readily available. It is very helpful when buying a new set of tires. I have read more than one post of an RV owner getting the wrong Load Range for their RV. This would be a serious safety concern.

Construction information on tire sidewalls

3. All tires also have information on their construction like this:

This is really just FYI and is more like truth in advertising. It’s to let you know the materials used in the sidewall and center of the tread of your tires. In this case there are two ply of polyester in the sidewall. In the tread there are two ply of polyester + 2 ply of steel + 1 ply of nylon. Most 19.5 and 22.5 tires will only have 1 ply of steel in the sidewall.

This information might help you understand why “ply” and “ply rating” are no longer used – since most tires only have 1 or maybe 2 layers in the body. This is why we use Load Range terminology.

But don’t worry, as we tire engineers have a large selection of materials and different strength of those materials so we can choose the appropriate materials for the tire we are designing.

Just as I did, you can capture a picture (bright sunlight is best) and just keep that picture so you can refer to it in the future.

OK, so now you are asking, “When do I get my free tires?”

You can check to see if your vehicle or any of your tires or other parts are covered under a recall HERE.  You will need the vehicle VIN and/or the tire DOT serial to check the list.

So where does having this information handy come into play? Well, let’s assume some day you have a tire failure or simply wear a tire out because an axle is out of alignment. So you replace it and give the worn or damaged tire to the dealer. BUT if that tire is on the DOT Recall list you could get it and any other tire covered by the recall replaced … FOR FREE.

But here is the catch. You have to turn in the old tire to get the free replacement. Just saying “I had a tire” will not work. Even having a picture is not enough. So just think of how you would feel if after replacing one tire or even your entire set, you were to discover the tires were subject to a recall but you no longer have the tires as proof.

NOTE: Tires are not the only parts that get recalled. I have heard of shocks or door locks or brake parts or wheels and many other parts being recalled and REPLACED for FREE.

Have a tire question? Sign up for Roger Marble’s new Facebook Group: RV tire news, information and discussion, hosted by and moderated by Roger. He’ll be happy to help you.

Read more from Roger Marble on his blog at or on


Roger Marble
Roger Marble
Retired Tire Design and Forensic Engineer w/50+ years of experience. Currently has Class-C RV. Previous Truck Camper, Winny Brave, Class-C & 23'TT. Also towed race car w/ 23' open trailer and in 26' Closed trailer. While racing he set lap records at 6 different tracks racing from Lime Rock CT to Riverside CA and Daytona to Mosport Canada. Gives RV and Genealogy Seminars for FMCA across the USA. Taught vehicle handling to local Police Depts


  1. As I never even thought about keeping the old tires when replacing mine, I am wondering if the tire sales stores have a “core charge” like when you buy a new battery and increase that charge when you don’t have or want to keep it.

  2. Is it possible that the DOT serial number on the tires can be different on both sides of the tires ? If you find out that is true what can you do ?

    • If you discover the DOT serial is different, other than the date portion on one side and not on the other, I would capture the codes with a camera and file a complaint with NHTSA. IMO the tires could be subject to a recall and possible replacement.

    • Looks similar to the 10 character example. Find the “DOT” on your tire then confirm you are looking at the serial that included the date portion. Very few tires have a “complete” serial on both sides of the tire.

  3. Went to Wal-Mart to purchase new tires for my truck. The correct size had finally showed up. Checking the date code, the “new tires” were dated 2 years and 2 months earlier. Did not buy them.


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