I have a 2012 FX4 with the 20" Pirelli tires. This morning I noticed that both my front tires have started to develop chunks missing from the tread right on the edge where the tread meets the sidewall. They haven't hit a curb or anything like that. The largest chunk is probably 3/4" x 1/2". Should I be worried about driving on these? I know I am probably one of the lucky ones that actually got decent miles out of these. I have 38000 miles on them now. I don't have any of the cracking near the bead that a lot of people do but there is some cracking in the tread I noticed when looking at them today.

 

This problem has been reported here on both the Goodyears and the Pirellis. Do you drive on a lot of dirt and/or gravel roads?
With what you describe, I sure would be replacing them without hesitation.

 

I do a little dirt/gravel driving but probably 90% is on pavement.