they may be, or so i thought. but they seem to still be offered by quit a few places. and i think they are still on the maxxis site. i ran into one guy that had them on his RZR, and swore by them. just depends who you talk to i guess. i still cant believe how well the reg zillas do in the nasty stuff. i would go far as to say that in my oppion, they have put a smile on my face , better than my last "true" mud tires, the Monsters. i mean they just get the job done. im not talking water riding, just nasty mud riding. so there i said it. Zilla's = stupid good tire for the nasty stuff. cheap too!