"How do I really know who made my tires and where they were made?"
As for where they were made, the tire sidewalls usually have a "Made In ....." marking; however, to know for sure who made the tire and where, here are some tips from a blog I follow:
On the tire sidewall is a DOT Code. That code includes a series of numbers and letters. The first two letters/numbers are the code for the manufacturing plant. The last four numbers indicate the week and year the tire was made (51st week of 2007 in the example below).
In this example, the plant code "U2" is a Sumitomo plant in Japan. How do I know that? Well, all tire manufacturing plants have a code from the National Highway Traffic Safety Administration (NHTSA). And I found a place within the NHTSA website where you can do a really quick search on that code.
The "Search Manufacturers Database" tool indicated in the image below ....
can be found at http://www.nhtsa.gov/cars/rules/manufacture/
So, look at your tires, get those first two letters/numbers from the DOT line, uncheck all the boxes on the left except "Tires" and "New Tire", and plug in the two digits in the DOT ID box in the bottom center.
Hit the "Start Search" button and in seconds you have the tire manufacturer and the address of the plant where the tires were made.
Or, if you want to see where all of a manufacturer's plants are, plug in the tire company name in the "Manufacturer Name" box at the top and you will get all their plants with addresses and their two-digit DOT codes.
Just remember that with RV tires, age is generally more important than tread since they tend to dry out and crack from UV rays before they lose tread. Hope this info helps some of the newbies or reminds anyone looking at purchasing an RV (either new or used) to check the tires. It is also not unheard of for someone to purchae "new" tires only to find out that they actually sat in a warehouse for 3 or 4 years before the purchase.