Yoko Geolanders Coming Apart

I have about 20,000 miles on my Yokohama Geolanders... there are pretty deep cracks at the base of the treads on all 4.... is this normal or is this a sign that they are coming apart?

 

i had a pair of geolander mts on a jeep they didnt crack but they were definately soft they were about half tread after only a few months and i didint drive far or anything

 

Definitely not normal, I would swing by your local Yokohama dealer and see what their thoughts are. Without seeing the cracks it is hard to say for sure, but most likely if they are cracking that badly Yokohama will give you a significant pro-ration towards a new set.