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6 Bolt Disc Rotors vs Centerlock Disc Brake Rotors

Many cyclists will meet the situation of choosing between 6 Bolt rotors or centerlock rotors, when building new wheels or just curious about braking performance for an upgrade.

How should we choose 6 Bolt rotors and centerlock rotors, which has no absolute answer. That depends on your needs and how much budget you are willing to bear.

It should be noted that the discussion about 6 Bolt rotors and centerlock rotors is limited to disc wheels. If you use rim brake wheels, you don't need to worry about this situation.

This article will tell you the difference between 6 Bolt rotors and centerlock rotors.We will look at the comparison from multiple and different angles for you, so at least by the end, you can see what suits you the best.

Before the article,you can see the video below,to know the difference between them.

The main content of the article

  • The history of brake rotors
  • Pros and cons of 6 bolt disc rotors

  • Pros and cons of Centerlock disc rotors

  • The history of brake rotors

The history of brake rotors

Before discs there were drum brakes, which tended to overhead and 'fade' in power. But when racing cars began to use discs in the 1950s, the new form of braking swiftly spread to all types of vehicles. In those days, bike brakes used the same basic principle as discs, with calipers which forced friction pads onto a spinning metal rim. The levers needed strong hands to operate them, and the fragile alloy rims could overheat enough during a long alpine descent to melt the glue that held tubular tyres on them.

Then in the Nineties came the disc revolution, in which the calipers moved down to hub level, and closed onto a spinning steel disc which was attached to the hub by a rotor. With hydraulic discs, a light touch on the levers was enough to lock the wheels. Mountain bike designers embraced discs, because they opened the way for wide clearances and fat tyres and greater freedom in frame geometry. The popularity of carbon fiber frames and wheels also pushed MTB brands toward the new disc technology. Road racers were slow to follow their example. But it wasn't long before

The six-bolt rotor became a dominant standard in the MTB world, despite a couple of design drawbacks.

Six bolts hold the braking disc to the hub's rotor; and discs vary between 140mm – and 220 mm for a downhill mountain bike with extreme braking needs. The bolts are fastened with a 6mm Torx key which has to be tightened in a specific pattern to meet precise torque numbers. Too tight and the bolt is stripped; too loose can cause failure out on a ride. New technology always brings new problems, and mechanics were soon learning how to cure discs that were squeaky, warped or mounted off-center. Fitting or installing a six bolt rotor system is not a job for a slapdash worker.

US Patent No. : US 6371252B1 was granted on April 16, 2002 to Shimano, naming the inventor as Takanori Kanehisa. This patent was for what became the Shimano Center Lock disc braking system. The invention managed to overcome most of the six bolt system's drawbacks. It became easy to fit and service the hubs. The discs did not warp or become decentered. But Takanori's design achieved these objectives with a couple of trade-offs. It was heavier than the six bolt system, and more expensive. And in addition it required the owner to invest in a specialized tool.

This is the Shimano TL-LR10. It is a torque wrench used to fit the rotor to the hub, and also to lock the cassette in place. The inner part of the Center Lock rotor is splined alloy, and fits onto the hub. This alloy helps to dissipate the heat that builds up under prolonged braking. The outer part of Shimano's rotor is hard-wearing steel, which resists warp. But it makes the Center Lock disc weigh in at 156 grams, compared to the six-bolt's 115 grams. Using the TL-LR10, the entire assembly locks into true alignment in a matter of seconds. Decentering is not a problem, and the job is soon done, even by an amateur mechanic. Of interest to many riders are the Shimano Ice Tech Freeza rotors, which halve the 500° temperature of the disc during a long descent. With special pads, the disc can get as cool as 300° and brakes keep their bite all the way down into the valley.

There is one important thing to first note with centrelock or 6 bolt rotors. Both Centrelock and 6 bolt hubs and rotors will work with your disc brakes wheels. It does not matter what the make or manufacturer is of your disc brakes. They will work with either rotor.

The reason for this is that 6 bolt or Centrelock names refer to how you attach your rotor to your hub. As long as once you’ve attached your rotor to your hub and it is centered correctly, you’ll see that your brakes don’t care and will grab it and slow you down regardless.

6 bolt disc rotor

 

Two types of installation

6 bolts require only 6mm torx key when the centerlock requires both a special tool and 24mm fork key.

The centerlock special tool known by the lockring is also used to remove the rear wheel cassette and it is considered as one of the essential maintenance tools for bikers.

Overall the center lock has quick installation and disassembly compared to 6 bolts.but corresponding tools are needed.

Weight

We know that 6 bolts disc rotor is lighter, but since the center lock comes with it’s adapter the comparison needs to be looked at from a different angle.If we want more accuracy we need to compare the weight of the total hubs.

By comparison Shimano XT FH-M600 with SM-RT64 center lock and Sram 900 hubs combined with SM-RT56.
We found that the weight difference between the two is more than 100 grams.So we can judge that the 6 bolts disk rotor is lighter.

Price

Due to many reasons such as increased production costs, the centerlock rotor is considered to be more expensive than 6 bolts.

Since these models are manufactured by major brands such as Shimano and SRAM, they are expected to be higher price than the 6 bolts rotors that can be manufactured anywhere else in the world.

6 bolts prices start from 10$ (unknown or unbranded) when Magura and Tektro vary between 20$ to 25$, on top-level Shimano rotors start from 40$ to 90$ for a pair.And the price of the top centerlock rotor ranges from US$35 to US$200.

Converting From 6 Bolts To Center Lock
Unlike the center lock to 6 bolts conversion which is considered easy and inexpensive, the 6 bolts to center lock is quite a challenge but at the end it is possible.

From this we can briefly summarize the Pros and Cons of 6 Bolts and Center Lock

Pros and Cons of 6 bolt disc rotors

Pros

Cons

Multiple rotor options

Easily stripped when fitting

Cheaper than Centerlock

Can fail when riding

Rotors are easily available

You can accidentally fit them off center

No special tool required.

Easier to warp

Less heat ventilation designHub treads get damaged under high torque.

Pros and cons of Centerlock disc rotors

Pros

Cons

Easy to centre

Less hub choice

Rotors are harder to bend

Heavier rotor

Open for 6 bolts conversion

Heat ventilation design.

Fast installing and removal.

It’s a bit expensive

Requires special tools

Centerlock rotors

 

Conclusion:

Six bolt kit is available in any shop anywhere in the world. But Center Lock parts are not so easy to source, in a wide range, especially if you insist on sealed bearing hubs. If you want superb design and convenience regardless of the cost – go for Center Lock. Also if you are one of those mechanics who are 'all thumbs', not fixated on weight or hooked on a wide range of parts.

You'd be better off with a six bolt system if you're on a budget, or a mechanic with patience, gentle hands and 'bike sympathy'. Especially if you need a wide range of parts and sizes. And above all, if you're an uphill racer who gains a second for every gram you shed. If you have Center Lock and decide to go back to the six-bolt system, Shimano has an adapter: SM-RTAD05. But going the other way is most likely impossible.

  • Aug 21, 2021
  • Category: Articles
  • Comments: 0