probalby like you said, "no love for drum" anymore. the issue with drum is not really inferior perfromance. they stop you jsut as fast as disc but at much higher maintenance. Disc are just more trouble free. I f disc was sthat much better then heavy duty rigs would have switched years ago. they mostly still run drum anc can stop 120K flying donw the highway pretty quick. drum has some other advantages in heavy duty applications as well, like more surface area of brake lining