I tried, in my mind, to chalk it up to something else (like sun, tire "protectant" products, etc). But a trend has developed that is frustrating to me. Pretty much every Michelin car tire I've owned (including two sets of the old Pilot XGT H4, two sets of the Energy MXV4 Plus, two sets of the X Radial DT, one set of the old Agility-now-WeatherWise-II, and now one set of the Energy MXV4 S8) has showed weather/ozone checking on the outboard sidewall at the base of the sidewall, down by the bead. This has happened to every single one of them, and it's in the same place every time...down in the inch closest to the bead. It's never produced any ill effects that I know of (leakage, blowouts, etc), but it's bothersome to me.
I've owned two sets of Michelin light truck tires now, including an 8-year-old set of the LTX M/S (on my old Nissan) and now two sets of the CrossTerrain SUV on the Acura MDX. None of the light truck tires have developed any of this cracking or checking, and the sidewalls of the light truck tires remained very pliable and "healthy" for years into ownership. In fact, even to the point of removing the tires due to wear, there were no signs of rot at all on the truck tires.
I've cared for all of my tires in a similar manner, and in fact, I've begun to stray away from tire dressings in the last few years. These Energy MXV4 S8 tires have seen few applications of dressing...maybe 2 or 3 times in their life. I've read that dressings (especially those with petroleum distillates) can degrade rubber. Regardless, I'm using Michelin's own branded dressing, so that pretty much removes the dressing as a variable.
As the OEM Energy MXV4 S8 tires on my Camry wear down to around 7/32" at the 12,000 mile mark, I'm starting to consider replacement. This time next year, they'll likely be at 4/32" and I'll be wanting to switch them out. Normally, I'd default to a Michelin tire, but I'm not liking this trend I'm seeing with their passenger car tires. My go-to tire would be the Primacy MXV4, but I'm beginning to think that I'll start seeing this checking or cracking shortly after purchase of those tires also, and I'd hate to see that after such a purchase.
Any comments on this trend? Has anyone else noticed the same? Am I simply worrying about nothing?