The white walls on the Corvette’s front tyres were badly discoloured. This discolouration may have been caused by heat from the brakes, or possible brake dust, but whatever the cause it had resisted all the conventional cleaning techniques. I had tried scrubbing, bleaching, cream cleansers, magic erasers and more, but the stains didn’t budge.
After a bit of Googling, I found a YouTube video (see below) that suggested wet sanding with 300 grit sandpaper, followed by finer 800 grit to smooth the surface. I decided to give this a try — you can see the results below. I spent around one hour on each tyre (I left the wheels on the car), finishing them with a coat of 303 Protectant. I think the result was well worth the effort.
Since writing this post, I've replaced the front tyres with another set of Mastercraft white walls. I found that the new tyres started to get a similar yellow stain on them as soon as the blue protective coating was washed off. Interestingly, the rear tyres (which are 10 years old) have perfectly white stripes, there's no discolouration at all.
Being so old, the rear tyres were made in the USA, whereas the old front tyres and the new ones I purchased are made in Mexico. My theory is that the quality of the white stripe on the Mexican tyres just isn't the same as the old US-made tyres. Has anyone else had a similar experience?
Some months after fitting the new front tyres, I purchased new rear tyres. These were 215/75R15 Mastercraft WSW — slightly wider than the 205s on the front. I purchased the rear tyres from a different supplier, but they're still made in Mexico. When I washed off the blue protective coating the white walls were perfectly white. I'm now thinking that the issue with the white walls discolouring could be just the 'luck of the draw'.
I've had the new Mastercraft white sidewall tyres on the car for more than 6 months now. I purchased the tyres in 2 batches from different suppliers — the fronts first and then the rears. The production date on the tyres showed that the 'new' fronts were actually a year older than the rears (2020 production versus 2021).
When I washed off the blue protective coating I noticed that the white band on the fronts was already showing some discolouration (a slight yellowing on the outer edge of the white band) while the rears were perfectly white.
I wondered at the time if this was due to the age difference, and sure enough, after 6 months of use the rears have also developed the same discolouration. Do all white walls do this, or is is just the Mastercraft tyres? I'm inclined to think this is due to inferior materials or manufacturing, it seems I'm going to have to learn to live with it.