I noticed on my rugged trail tires that there was considerable cracking in the outer 2 grooves and none in the center groove. With only 17k miles and a little over 2 years old, these tires should not be having this problem. For those that think that over/under inflation or too much weight, the tread is completely even and no evidence of improper inflation. Except for the cracking, the tires were in very good shape. I took them to discount tire (where I had purchased a lifetime balance and warranty 8 months ago). 2 different guys, including the manager, came out and said there was "borderling separation" but clearly the tires were breaking down enough where they wouldn't drive with them. They agreed that improper inflation was not the issue.
I didn't say anything about the warranty, just to get their honest answer. They copied all the DOT #'s off of the tires and called Michelin (owner of BFGoodrich) to explain what was going on. Michelin agreed that they should be replaced asap and gave me 75% (of the original cost of the rugged trail) credit toward new tires. Luckily the warranty I bought covered the other 25% and so I got some BFG KO's. The tire cost was only $6 more per tire than the cost of the Rugged trails.
So I got some new rubber for $24 and the cost of installation. Not bad, but check those Rugged trails! I'm thinking that Michelin knows how crappy these tires are and seemed very willing to get these tires off of my truck. I don't know what my DOT numbers were, but the tires were date stamped 1105, which I believe means 11 week of '05.
Love the new tires, so far ride smooth on city and highway streets.