On my first set of Michelin tires on our current coach the steer tires were made in Spain. After about five years there was a bit of sidewall cracking. I did not get the alignment done so replaced them before the cracking required replacement. However, my drive tires were the same age and made in the USA. (The drives were 12Rs and steers 315.) The drive tires showed zero sidewall cracking until I replaces them at just over six years old. So there must have been some difference in the tire rubber compound.
If we will be packed more that a few days I cover my tires. That cuts down on the UV damage.
Country Coach 42' Affinity
2013 Jeep Wrangler Unlimited