For the most part, bikes are pretty simple machines. Well they used to be. Now we’re in an era where bike “standards” are reinvented every five years for the sake of making money. Take for example brakes. I’ve lived through the evolution of various rim brakes, with mountain bikes having settled on disc brakes two decades ago. *be patient with our roadie friends, they’re just coming around.
Disc brakes use 6 bolts to secure to rotor to the wheel hub. The bolts are torqued to ~5nm and that’s that. But Shimano had to come out with an “improved” method to secure the rotor which they named Center Lock. Center Lock uses a single lock ring instead of 6 bolts to secure the rotor to the hub. The wisdom according to Shimano:
The CENTER LOCK system makes an easy rotor installation possible with spline mount and a lock ring. The lock ring mounting system reduces the total working hours by shortening the amount of time of both installation and de-installation. In addition, the secure fixing by the spline mount enhances precision and rigidity while improving braking efficiency.
Having used both types of mounting systems, I can’t say Center Lock improves braking or is any more secure. Actually I’ve had to retorque my Center Lock rings which has never been needed for my 6 bolts. But I’m not a fan of how easily those 6 torx bolts can strip either. How about changing those torx heads to hex like the rest of the bike?!
I’ll agree with the first part Shimano’s statement that Center Lock removal and installation is faster. You’re only turning 1 fastener per rotor instead of 6, kind of like Formula 1 vs NASCAR wheels.
Maybe that’s where Shimano got their idea.