I have been fighting the good fight on this issue for 2 years now. Have spoken to Michelin, owner of Goodrich numerous times. Gotten all types of stories, none admitting that the have a problem.

Posted on many forums including this one. Been told that I do not know how to detail tires, been told to use this chemical product or that one. Believe me, I have used them all,,even sandpaper and pumice.

I've run these tires for for 40 years. Until recently I had no issues with the letter discoloration.

The last set I purchased for my 1971 Corvette 275's and 255's immediately turned brown. Replaced all 4 of them twice,,,,as soon as the blue protective coating has been removed they start to discolor to brown.

I have 2 friends with Mopars place 275's rear 235's front. 275's immediately turn brown, 235's remain white.

Current belief is that Michelin changed formula for the rubber for whatever inane purpose on their larger tires,,,smaller one's likely later will be hit.

As soon as blue protectant is removed and air hits the white, a chemical reaction occurrs,,,,think what happens when you slice an apple or a pear and leave it set out for a bit.

I have posted photos earlier in this thread. Take a look at photos of some TA's that are likely 15 years old,,,,Snow White. Take a look at almost new TA's ,,,toasty brown.

I have a major show coming up, I now will be flipping the white letters in as what I now have is so embarrassing and people suspect you are a lousy at detailing.

Here are a couple of photos taken today. By the way, the best I have dreamed up for cleaning the letters to somewhat white, is a buffing tool like a Dremel or an air powered,,,using a white dry pad. Goof off works somewhat but not near as well. Both very tedious and temporary.

The final photo is of a 235/60 on a friend's RR. His rear 275/60's are as brown as mine. All bought same time from Discount Tire in Az.

I have now installed bias Polyglas GT's on my Challenger. Goodrich TA's are no longer for me after some 40 plus years of happy use.

By the way, I am now convinced that not only the raised white letter turn brown,,,but the black on the tires also do. You just don't see it and tire conditioners clean them up, whereas does nothing for the white lettering.

These issues could also be manufacturing plant specific,,,some 7 plants produce these tires, perhaps more. Mine are out of Ardmore Ok. I say avoid this plant,,,but again perhaps they are all bad. Dot code on tires will give plant I'd.

I suspect they have added silicone to their rubber causing the air related browning. Likely for some manufacturing efficiency or some such reason,,,likely to make a few more bucks.

If you do purchase, I recommend your local supplier, not online as if warranty replacement is sought, freight shipping and mounting charges will eat you up. Sorry Tire Rack.

Forgot to mention. I no longer believe that browning is caused in this case by the oils in the tires by osmosis working its way up into and thru the lettering. I am now convinced that Michelin has reformulated their rubber. I have certain evidence for this revised opinion.