I bet that few of you have ever bothered to read and copy down the important information provided on your tire's sidewall. There are a number of reasons for you to spend the few minutes it will take to collect and write down the information. Having the facts, might even be worth a free set of tires!
1. DOT 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, the division of the US DOT that is responsible for initiating recalls of vehicle components that have been judged to not meet the safety standards that DOT establishes. For tires, the DOT Serial 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 and to collect the serial number on a nice sunny afternoon, than on a rainy morning in the mud. You need to include all the letters and numbers, especially the last 4 numbers which are the "Serial Date Code" that 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 as it is well over the 10 year Max age limit for any tire in RV application.
When you start looking at your tires you may find something that looks similar but the last four characters and not numbers. This means you need to inspect the other side of the tire as not all tires have the date code on both sides. I have suggested a flashlight and a 12 year old and a $5 or $10 bill might be called for as you hire some young helper to collect the Date Code from the other side of the tire. I know, that I no longer find that crawling around under my RV is easy on the knees. 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. Don't move the RV with the 12 year old under the RV. Not Safe! 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 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 easily 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 which would be a serious safety concern.
3. All tires also have information on their construction like this:
This is really just FYI and is more like truth in advertising 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 and in the tread there are two ply of Polyester + 2 ply of Steel + 1 ply of Nylon. Most 19.5 & 22.5 tires will only have 1 ply of steel in the sidewall. This information might help you understand why "Ply" and Ply rating" is no longer used since most tires only have 1 or maybe 2 layers in the body. This is why we use Load Range terminology.
Don't worry as we tire engineers have a large selection of materials and different strength of those materials so 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 you 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, lets assume someday 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.