Originally Posted by
kcjc
Uhm? That's BS. At worst, you would end up with a chain that might be too long. It's based on the chain ring and rear derailleur; branding plays no role except for the length of the derailleur cage (and pulley for those that buy into that crap) and the number of teeth on the front chain ring. My bike on the trainer is a mix of drivetrain, and it works fine if you follow directions.
You could certainly end up with a chain that's too short if you sized the chain based on only the small chainring and the small cog. The small chainring and cog have no idea how big the large chainring and cog are.
Accidentally follow the procedure in that video with a short cage derailleur and an incompatible wide range cassette and crankset. Your drive train will be damaged the first time you shift into big-big.
Try it.