In my previous post, "Browning of White Tires --- A Theory and Why", I presented a theory that I have been working with and researching for the last two years, as to what is causing the white tires (and gray tires) to turn a brownish color within a few months of installing them. Here is a general summation of the theory and what has been found to support it. For more details please see the previous post "Browning of White Tires --- A Theory and Why".
The theory is that the problem stems from the tubes, and more specifically, tubes that were marked "Made In EEC".
The case that made me focus on the tubes as being the source of the problem was when one of my 15 year old white tires on one of my own cars went flat. The tube had failed near the stem. I replaced the tube and within a couple of months, that 15 year old tire had turned brown.
The only thing that had changed was the tube. The tube in it was marked "Made In EEC".
As I investigated this, I found the tube to be a common thread with most all of the tires that had the problem (Where I could confirm the type of tube that was in the tire at the time of the problem).
This theory has been met with more than a little resistance, and for good reason. The inside of these tires do not turn brown like the outside and the thought of some chemical passing through the tire and only affecting it on the outside were it is exposed to the atmosphere, is a little hard to swallow. But there is more evidence to support that this IS what is happening.
In the photo of the Universal straight rib tire above, please note a couple of things. If you were to take a cross section of this tire, you would realize that it is discolored more where the tire is thinnest. The raised bead on the sidewall and the tread area are not as brown. Also the area covered by the rim is still white. Also of great interest is that this tire did not have a rim flap in it.
The photo above is a good example of what happens when the problem occurs AND the tire has a rim flap in it. The lower part of the sidewall is partly protected and does not discolor near as much.
The good news at this point is that the tubes that were marked "Made In EEC" are no longer made. I was told by two sources that the company that was making them went out of business. My biggest concern at this point is whether there are any tubes, currently in production, that are causing the issue.
So... If you know what tubes you have in your white tires, please let us know whether they have stayed white or turned brown. We need to know what works along with what does not work.
Sometimes I hate this forum software. I made a mistake in the title line and left "Part 2" out of the title. Can't correct it so I am re-posting.
Please see "Browning of White Tires "PART 2" --- What Tubes are in Your Tires?"
Sorry for any confusion.