Back Issue | Grouptest: Six of the best disc brakes

When we ask ourselves why we ride, we all share the same answer: we ride because we love going fast. That delirious feeling when the world gets a little blurry, and time simultaneously slows down and speeds up. However, sometimes we have to control that dizzying speed, and that is where good brakes can make all the difference.

Update June 2016: We’ve got a more recent disc brake group test with 13 brakes in comparison

It’s generally pretty hard to get excited about brakes—not often the sexiest component on a bike—but if you pull that lever in anger and they don’t work, things escalate pretty quickly. Luckily, brakes have become a lot more reliable and predictable, and grabbing a handful of lever is like throwing an anchor into the dirt. Our biggest problem now is dancing that fine line between traction and locking up the tires. We tested six of the best to see how they perform in the laboratory—and on the trail.

Lab Testing

Everyone knows that modern disc brakes have enough power to rip the skin from the earth, so in order to expose any weakness or unreliability in this group test, we needed to push them to the absolute limit — and then kick them over the edge. Taking them away from the trail and into the laboratory, we could force them far beyond normal usage. We took the testing to Hope Technology’s in-house development lab in Barnoldswick, where we analysed each brake using a sophisticated computer-controlled dynamometer, measuring every parameter with scrupulous accuracy. Sensors measured temperatures and braking torque, and human preconceptions and bias were removed from the equation — all weaknesses shouted out loud.

In the lab, brakes were tested with the OEM pads and their dedicated 180-millimeter rotors. After running a long bedding-in process, the computer simulated repeated breaking cycles from 30-15 km/h, representative of normal riding, allowing us to measure the power and deceleration time in normal use. Then the test was turned up to 11 — glowing red and spitting hot sparks, the brakes were decelerated hard (50nM lever force) repeatedly from 45-0 km/h, a brutal test designed to bring on ‘fade’ (gas produced from hot pad resin, decreasing friction) and see how the caliper handled the heat buildup.

Lab Results

After extensive testing, the air was heavy with the hot metallic smell of burnt brake pads and scorched rotors — and the results were in. Amazingly (and credit here to the design teams), all the brakes performed exceptionally well, remaining powerful and effective even after repeated high-speed braking abuse. The laboratory standout performers were the Shimano Saints and the Magura MT5, both able to decelerate the heavy flywheel from 30-15 km/h in only 1.2 seconds, twice as fast as some of the competition.  But that is only half the story; we needed to see how the brakes would perform on the trail.

Trail Testing

“Power is nothing without control,” and a tyre can only put down so much braking torque before grip is exceeded and things get rowdy. The best brake is one that allows you to put down ‘just enough’ power to provide maximum deceleration without initiating a skid — and that requires modulation. In order to see which brake could deliver power smoothly, our test team rode each extensively on the loose and slippery trails of the Tweed Valley in Scotland.

Formula CR3

The CR3 brake is brand new to the market and is delivered at a really good price. Borrowing the cartridge design from the C1 brake and putting it in a new radial-style master cylinder provides a little more power and control. The caliper uses two oval pistons which are slightly smaller than in their flagship R0 brake, applying the power in a more manageable fashion.

The CR3 is the lightest brake in the test and saves over 150 g when compared to its heaviest competition (the Saint), but that is certainly not at the expense of power. We also really liked the Speedlock quick disconnect system, which allows the caliper to be disconnected and reconnected for internal routing without having to re-bleed the brake. Teaser videos before the brake was launched promised multiple tool-free adjustments on the lever, but these aren’t evident on our production models. The only adjustment is the reach, via a small Torx bolt. It would have been nice to see some form of contact control.

On the trail, the CR3 was a good performer, providing dependable deceleration. However, when tested back to back against other brakes, the lever feel was a little wooden. There is certainly a lot of power on offer, but it comes in quickly and is hard to feather over loose ground. The Formulas certainly offer an improvement in feel compared to the violent Formulas of old. But that’s a bit like being well-behaved…for a murderer.

PROS
Lightest in test
Good power

CONS
Excessively rapid power delivery
No tool-less adjustment

Hope Tech 3 E4

The one piece CNC caliper and Tech 3 lever are manufactured in-house in Hope’s production facility in Barnoldswick, and the machined T6 aluminium body looks stunning. The new lever has a very effective bite point and reach adjustment without the need for tools, but the useful flip-flop design has been lost.  We found that the lever controls were the best on test, allowing us to get the brakes just like we liked them, while still being easy to operate wearing gloves. The Tech 3 levers are very moto-inspired, and they polarised some testers, looking a little agricultural next to the slick ergonomics of the Shimano and SRAM levers. However, the burly levers are very strong and shrug off impacts well. The caliper houses four 16-millimeter phenolic pistons which promise functional power, and impressed with a very respectable braking torque of 96.9nM during testing.

What impressed us most on the trail was how they deliver their power: torque is applied in a smooth, progressive fashion (the slowest deceleration times in the test), and modulation is extremely high. You have to pull a little harder than with the others to really brake hard, but the power is there should you need it. Where the Hopes excel is in loose or muddy terrain, providing class-leading modulation. The Hopes proved very resistant to fade in both the laboratory and on the trail, and had a robust and reliable feel. If you get excited by beautiful machining, you will love the E4 and Tech 3 lever. If you love modulation and smooth power delivery, the Hope is the best in the test; however, we found more power is available at a much cheaper price.

PROS
Beautifully machined
Class-leading modulation

CONS
Beauty is expensive
Strong fingers required

Magura MT5

There is a lot of new innovation in the Magura MT5, perhaps most notably its new magnetiXchange replacement pads that magically lock themselves into the correct location. As the Magura’s use Royal Blood mineral oil, bleeding is also a less toxic affair than some, and a simple process. The MT5 brake comes standard with two organic brake pads per caliper, but these are also compatible with the four individual pads from the more expensive MT7 brake. The only thing we missed was tool-less reach adjustment (they require a T25 torx key), and it has to be pointed out that the excitingly named “Carbotecture” lever clamp material looks a little cheap, as do the fast threaded clamp screws. However, some of our testers liked the utilitarian look and we could certainly not fault the performance. We liked that the lever can be mounted on either side and found the long blade was easy to locate in a comfortable position. The ergonomic aluminium lever has space for one- or two-finger braking. However, with power like this, using two fingers would be like riding into a wall.

During testing, braking torque and deceleration were brutal – but there was a delicate sensitivity present too, like a rhino in ballet shoes.  The Carbotecture fibre composite material is certainly light, offering almost Saint-rivalling performance, but at a big weight and cost savings. Throughout the tests they proved reliable and the lever bite point did not shift once; again and again they provided dependable stopping power. Magura have shown that you can have it all, and with a five-year warranty, they take the Best in Test award with ease.

PROS
Massive power and control
Five-year warranty

CONS
Lever looks cheap
Slow pad bed-in

Shimano Saint

The Shimano Saint is a legend from the DH world. The burly four-piston calipers provide massive stopping power (116.9Nm on the dynamometer) and yet only weigh 40g more than the two-piston XTs. Looking at the lab output, the Saint was the clear group winner when it comes to temperature management and resistance to fade, providing consistent and powerful fade-free braking during the 45 – 0 km test. The short bladed lever is very comfortable to use and works well with smaller hands, and we liked the added dimples for grip. With a tool-free reach adjust you can position the levers just where you want them; however, the ‘Free Stroke’ adjuster is a simple screw and has no place (or even a discernible function) on such a stylish lever.  Like the XTs, bleeding is a very simple process and can be done in five minutes. The Servo Wave lever action pushes the pads toward the rotor quickly, then smoothly through the bite point to increase modulation. But with so much power comes great responsibility.

On the trails the Saint is violently effective: The very aggressive Servo Wave lever allows you to lock a wheel with one finger easily so you have to be careful if available grip is low. Braking is so brutal, in fact, that it might be less forceful to actually hit the tree you were trying to miss. However, once you get used to the sharp bite, you can modulate the braking force well. They provide more braking force that you really need unless you live in the Alps or are huge, and on loose or boulder-strewn terrain it can be a bit of a carnival trying to maintain traction under aggressive braking. However, if face-altering deceleration is your thing, you will love the Saints.

PROS
Brutally powerful
Amazing fade resistance

CONS
Useless bite point adjuster
Heaviest in test

Shimano XT

Ever since their introduction in 2012, the Shimano XT brakes have served as the benchmark for affordable trail/enduro brakes. The XT lever has one of the nicest feels in the test, snapping back with machine-gun precision. The ergonomics are exceptional, and the reach adjust is quick and effective. However, at the end of testing there was a little more lateral lever wobble present when compared to some of the other brakes, and design has moved on a little now as the XTs were the second heaviest in the test. With a proper bleed kit, bleeding is exceptionally simple and with mineral oil it means you can slosh it around the workshop without fear. Lab results were impressive, a solid performance with little degradation in performance over the testing process.

When it came to the trail, the Servo Wave lever results in a snappy response — you either love the feel or hate it. Power is swift and precise, inspiring confidence and effective performance. It is only when the XTs are ridden back to back with other brakes that the feel starts to feel a little too snappy and lacking in modulation. The power is there immediately when the levers are pulled, but when at high speed on loose ground they feel outclassed — it’s hard to hold them on the traction point. You cannot argue with the value though, and the XT’s take the Best Value award with ease.

PROS
Great value
Easy bleeding process

CONS
A little heavy
Overly rapid response

SRAM Guide

This is the brake that everyone was waiting for, and indeed there is a lot to like about the SRAM Guides. The neat, narrow levers are well shaped for a variety of hands and the Contact Adjuster functions really well, allowing you to dial in the bite point just where you need it. It’s easy to tell that SRAM have spent a lot of time on the ergonomics. The same cannot be said about the tool-less Reach Adjuster. Even though it lets you set the lever exactly where you want it, we found it was often sticky and uncomfortable to use without gloves — and one fell out altogether. We like that the levers are ambidextrous, allowing them to be run on either side, and the use of bearings in the lever pivot give the lever a smooth and precise feel. The four-piston caliper uses dual diameter pistons, 16 millimeter at the front and 14 millimeter at the rear, providing powerful braking performance, averaging 96.3 Nm of torque in testing. However, we did observe the largest amount of brake fade during the 45-0 km/h test.

On the trail, the SRAM Guides delivered good performance, though all testers reported that they lacked the positive bite of some of the other models. The levers feature a special cam called the Swinglink, requiring less lever throw to push the pads towards the rotor, then slowing down through the contact point (improving modulation). The Guides also have three times the fluid volume of the old X0 to improve reliability – however, the bite point did shift a little as they heated up on long runs. Our long-term tests have shown that the Guides require little maintenance, and the large reservoir seems to minimize the need for frequent bleeding. Overall, the SRAM Guides were good brakes and performed well, but were outclassed by exceptional competition.

PROS
Beautiful lever action
Powerful

CONS
Brake fade in the lab
Noisy during testing

Conclusion

In testament to the quality of modern brake design, all six brakes in the test provided exceptional stopping power and modulation, performing very well. Each and every one impressed in both the laboratory and on the trail. The brake buying decision can no longer be based purely on reliability and performance, as personal preference is now the dividing factor. The Hope was the king of silky smooth modulation, the Shimano XT performed with reliability and gusto winning the Best Value award, the Shimano Saints continue to define deceleration, and the Formula CR3 was both light and reliable. We expected a lot from the new SRAM Guide and indeed there was a lot to like, but in the end they were outclassed by our group test winner, the Magura MT5. Looking past its ugly duckling lever clamp, the MT5 offered powerful performance, innovative features, and uncompromising reliability throughout the testing. Not only that, but the MT5 was the second lightest making it the clear test winner for the Best in Test award.

Update June 2016: We’ve got a more recent disc brake group test with 13 brakes in comparison

Words: Trevor Worsey Photos: Trevor Worsey & Fabian Rapp