I found this on a Corvette forum. I hope newer BFG’s don’t have this problem. Guess I should have used Google before posting....
“I also have "Goodrich" Radial T/As that are about a year old and will not stay white regardless of cleaning technique. For the record Michelin acquired BF Goodrich several years ago. Somewhere in the transition, probably because Michelin doesn't produce many, if any white lettered tires, they include what they referred to as an ozone protection package in the chemistry of the rubber compound. A side effect of this protection package is that the letters turn brown within a couple weeks of cleaning and get to where they flat out won't come clean. Michelin says that eventually, like after 1,000 miles, the effects of the protection chemicals will wear off and the white will become white again, though also say they'll replace them if you prefer, though assuming replacement tires will do the same, whats the point? Wesleys, Comet, Degreasers and other strong detergents don't work for crap once the letters have turned brown, as one person replied, the only thing that works is to wet sand them, I find 100-120 grit works pretty well, it will take about 25 minutes per tire to carefully resurface the letters to restore them back to white, though I can tell you, the brown will come back in about a month.”
“I also have "Goodrich" Radial T/As that are about a year old and will not stay white regardless of cleaning technique. For the record Michelin acquired BF Goodrich several years ago. Somewhere in the transition, probably because Michelin doesn't produce many, if any white lettered tires, they include what they referred to as an ozone protection package in the chemistry of the rubber compound. A side effect of this protection package is that the letters turn brown within a couple weeks of cleaning and get to where they flat out won't come clean. Michelin says that eventually, like after 1,000 miles, the effects of the protection chemicals will wear off and the white will become white again, though also say they'll replace them if you prefer, though assuming replacement tires will do the same, whats the point? Wesleys, Comet, Degreasers and other strong detergents don't work for crap once the letters have turned brown, as one person replied, the only thing that works is to wet sand them, I find 100-120 grit works pretty well, it will take about 25 minutes per tire to carefully resurface the letters to restore them back to white, though I can tell you, the brown will come back in about a month.”
