The instructions also say you can't shift, you'll go blind and your children will become sterile if you don't use the new super ultra special 5700/6700/7900 chains. The bike I just built using Ultegra 6700 shifts just fine with the same KMC X10.93 chain I've been using for years. You can never tell how much of this stuff is true or how much is just marketing BS. Although my vision is blurry...
Hah that's funny. My bike has Ultegra cranks/rings, Ultegra RD, SRAM cassette and SRAM chain. Reading the Shimano marketing materials, I must be ruining my entire drivetrain with every ride
My vision is fine, BTW.