New Rear Tyres
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'.