The browning happens with ALL white letter tires that I'm aware of. Bleach White spray and a scrub brush when you wash the car will bring them back to pristine white again
This particular problem will not be resolved with bleach white spray. I have had 3 sets 255/60/15 and all 3 sets have had this problem. This seems to be the only size having this problem. The only way to fix is with white paint pens.
My Vette in question has 275's on rear, 255's on front. All tires have this problem. Hopefully this 3rd set will remain ok.
TA's that I ran before this bad run of tires were all fine. Have owned the car 43 years and gone thru several sets of TA's on it.
Have run Diamondback wide white walls on a couple other cars. White walls are always perfect,,,,except for my first set in 1994. They browned up badly on outer edges of white walls. Diamondback replaced all under warranty. They had not yet perfected the shield that they place between the tire and the vulcanized on white wall technique they use.
The best wide white radials anywhere.
Here are a couple shots of the original Diamondbacks that were replaced under warranty. This was the mid 90's. The replacement tires have been on the car almost 20 years, the white walls are still perfect. The final photo is one of the 20 year old replacement tires, taken a couple of years ago.
Note the brown staining on outer edges. Their shielding process was failing. I suspect some like issue is causing the TA raised letter browning,,,,although have no knowledge of what process Goodrich adopted to prevent browning.
