Should you be interested in buying a new set of hubs for your bicycle you might want to know which are more convenient: for centerlock rotors or the classic 6 bolts interface hubs? We’ll present the advantages and disadvantages of each type of mounting so that the conclusion belongs to you.
As a brief introduction, you should know that 6 bolts IS (International Standard) or Centerlock are not the only standards. There are also other types of mountings some less known, as the 4 bolts rotors from Cannondale, the 5 bolts rotors from Hope or the ones patented by RockShox and Rohlhoff in the past.
As the first two standards are the most common, having succeeded in imposing themselves on the market, I would like to start with the Centerlock standard, considering the 6 bolts mountings sufficiently clear for everyone. Centerlock is a Shimano patented by system, facilitating the installation process. The disc is placed on the hub as you can see in the picture below, and then simply locked with a special key. Contact surfaces between the hub and disc are generally made of steel, for an increased durability of the system.
The disc is riveted to the hub mount and although some might argue that rivets could develop a margin in time, I have never heard about such a case. A special wrench, which can be also used for removing cassettes will be used to secure the rotor to the hub (Shimano, model TL-LR10).
This key can be purchased from any store at small price (typically 10 euro for an original Shimano key and 5 euro if it’s coming from other manufacturers). Keep in mind, if you use a 20 mm thru axle front hub, you will need to purchase an oversize mounting Centerlock rotor, and also a different key ( Shimano, model TL-LR20).
A Centerlock hub (e.g. Shimano XT – 230 grams including Quick Release) weights less than a 6-bolt hub, usually due to the larger size of the screw flange (Shimano XT large flange weights 316 grams including Quick Release).
However, a Centerlock rotor is heavier than one with bolts (156 grams for a Shimano XT Centerlock Rotor, compared to 115 grams for a Shimano XT 6 Bolt Rotor, both rotors with a diameter of 160 mm). A simple calculation shows that a Centerlock system weights 45 grams less than the 6 bolt system (Shimano XT with hub and 160 mm rotor). Is this irrelevant? It’s up to you to decide!
Regarding 6 bolt hubs, these components enjoy the advantage of accommodating more than 90% of the rotors available on the market. They do not require a special key but a Torx driver (found in almost any pocket tool set). On the other hand, if fastening is not done properly there are two risks: either destroying the threads by fastening them up, or the thread is destroyed in time by brake vibration if you do not fasten the bolt enough. However, manufacturers offer accurate data regarding the force to be used for fastening these bolts (in Nm – this is why a torque wrench is recommended for tightening). .
In case you don’t want to use a Shimano rotor on a Centerlock hub, you can purchase an adapter like the one below. DT Swiss sells it for quite a low price.
Advantages for Centerlock
– easy to install, easy to remove
– smaller weight for the hub
– rotor is perfectly centered (6 bolts rotors have to be manually centered)
Disadvantages for Centerlock
-requires special key for (un)mounting
-comes in two sizes (standard and oversize), so two different keys are required
Advantages of 6 bolt mounting
-compatibility with most rotors
– large choice of hub
– anyone can mount/dismount a rotor with a Torx wrench (or use a star key for fastening in the opposite way)
Disadvantages of 6 bolt mounting
– may be wrongly centered
– threads can be damaged by excessive/too weak tightening
– takes longer to (un)install
As I said in the introduction of the article, the decision is yours! Each system has its advantages and disadvantages, and each one should be able to conclude which is best for him or for her. The good news is that despite the differences, the bicycle market adapted both systems, as 6 bolt and Centerlock hubs are most widely used at present