Monthly Archives: February 2013

Shimano Center-Lock vs. 6 bolts disc hubs & rotors

How quick time goes! It’s ten years already since Shimano released its own mounting system for disc rotors (XTR 960 groupset) … and still not popular in our bikes! Why?

Centerlock is a Shimano propietary method of attaching brake rotors to a wheel hub. The disc rotor offset is the same as international standard so that a Shimano Center-Lock rotor and hub are compatible with any brake caliper system around.

First Shimano Center-Lock disc rotor: XTR 960 SM-RT96

First Shimano Center-Lock disc rotor: XTR 960 SM-RT96

Legend has it that Shimano came out with Center-Lock after facing losts of warranty issues on their hubs in just a couple of years. Just imagine the consequences of stripping the threads or round a head bolt. Nothing a bike mechanic has not ever dealed with. I think it was an idea that simply came up considering manufacturing costs process.

Cyclists usually complain about how often companies renew their catalogues and technologies. But in this ocassion I’d like to stand up for Shimano Center-Lock interfaces considering all the advantages they brought up and how fast Shimano reacted to develope a new standard.

It seems we are undergoing a revival breaking the deadlock. That’s why I would like to sum up all the pros and cons of having them installed. With only two downsides the choice it is only a matter of money ­čÖé

  • Ease of assembly and removal saving a lot of time and making life easier to those riders that often travel and disassembly their rotors not to suffer any damage in transport.
  • Slightly lighter hub. Even though the lightest rotors in the market are not Center-Locks.
  • You can still use an adapter to convert to a 6 disc bolt pattern.
  • As for as performance and reliability none of the two designs are better, but Center-Lock still prevents stubborn bolts or ruined threads.
  • The diameter of the hub flange is smaller in Center-Locks. As a wheelbuilder you will find a lot easier with certain hubs to have less spoke length discrepancy between left and right side, specially in front disc hubs where one of the sides has no dish, and as a result, a more similar tension in both spoke sides. Remember that spokes are likely to come loose with low tension, and not dished side of them will be tensioned accordingly less. If a 6 bolts hub has been built with both oversize flanges just to minimise this effect, it will be for sure much heavier. For example XT 756 vs. XT 760 front disc hubs. I’ve come across with 8-10 mm shorter spokes in 6 bolt wheels, even though front wheels carry less stress and are much more reliable by themselves so that spoke tension is not an issue. About the rear ones there is no difference at all.
  • You need a cassete removal tool instead of a more common T25.
  • Larger range and availability of 6 bolts rotors.