Speed is nothing without control, which is why the faster you go the better your brakes need to be. And, to date, the best method for bringing a mountain bike to a halt quickly and smoothly is with hydraulic disc brakes. So let’s look at the best mountain bike disc brakes currently on the market.
Before the arrival of disc brakes, mountain bikers relied on cable-actuated rim brakes and although they fared well enough back then, it’s doubtful they’d be up to the task today given how far the sport has been pushed in recent years.
There are dedicated kits specific to the different brands of brake if you fancy doing this at home but, of course, you can always get the job done at your local bike shop
Improved braking power, feel and consistency regardless of conditions are the main advantages a hydraulic system offers but they also mean you can carry on riding (and stopping) if you damage your wheel. Better still, they don’t rely on the rim to provide a braking surface so the act of braking doesn’t involve increasing the wear on your wheels.
To get the best out of your disc brakes there are a couple of things you’ll need to do that you wouldn’t with rim brakes, but they’re easy to learn and don’t take much effort.
The first is bedding them in. All this means is performing a few hard stops to heat up the pads and transfer some pad material on to the disc to give them some extra bite.
The second is occasionally bleeding the hydraulics. This involves removing and replacing the oil in the system and serves to stop your brakes feeling spongy and soft. There are dedicated kits specific to the different brands of brake if you fancy doing this at home but, of course, you can always get the job done at your local bike shop if you’re in anyway unsure about doing it properly.
The latest Guide RSC comes with a bucket-load of adjustability, including a bite-point adjustment dial that actually makes a significant difference to where the pads contact the rotor. Lever reach can also be adjusted with an updated knob that has clearer clicks and no creep.
New Bleeding Edge porting works superbly to banish bubbles too and reliability across the Guide brake family has been relentlessly excellent.
From June 2016, the Guide RSC also gets the same S4 calliper as the top-end Guide Ultimate, including remodelled, heat-shielded, bi-material pistons and new seals and shaping for outstandingly consistent control on even the longest, most demanding descents. The result is consistently rich and impressive modulation that eclipses anything else you’ll find.
Acres of adjustability that makes a noticeable difference
Broad, servo-wave levers get grip dimples for extra measure
The SLX M675 delivers all the best parts of Shimano performance at an excellent price.
The levers are broad, deeply crooked and get extra grip dimples and a big reach adjuster dial on the knuckle. They also use a variable-leverage Servo Wave cam to connect to the master cylinder, which means better pad clearance for quieter, cleaner running, as well as increased power at the contact point.
Even in standard trim (without the Freeza and IceTech cooling aids), SLX are some of the most consistent, predictable and communicative brakes around in general UK use.
They don’t have the largely ineffective ‘Free Stroke’ screw of XT either. Whether that’s the cause or not, we’ve had none of the random bite point issues of some XT and XTR brakes over the years.
A reliable set-up with plenty of power for challenging trails
Great levers with loads of adjustability
While the Guide R is cheaper and looks similar it lacks the RS S4’s internal ‘SwingLink’ cam that creates more clearance between the pads and rotor, resulting in quieter dirty weather running without reducing power or modulation at the contact point.
You don’t get the bite-point adjustment dial of the Guide RSC brakes, but you do get a tool-free reach-adjustment dial. The distinctive arc of the broad blade lever amplifies average power in practical terms and it always feels pokey enough for challenging trails with a 180mm rotor.
New, simplified Bleeding Edge porting is a joy to use and it’ll handle sintered pads fine without any heat issues. Add excellent reliability, flawless syncing with other SRAM controls and reasonable weight and the Guide RS is a top cost-effective, uncompromised performance option.
I-Spec shifter integration and surprisingly durable pads
Shimano’s basic Deore delivers the best performance in the budget brake market, even if they don’t get the tool-free reach adjust of the more expensive models.
There’s no dimpled grip detailing on the broad lever either but feel remains excellent, with impressive modulation being the obvious gain over cheaper Shimano sets. You also get a hinged safety-catch-equipped bar clamp with I-Spec shifter integration for a neat cockpit set-up.
Pads are secured with split pins not screw-in rods, but we’ve found the original resin sets to last surprisingly well even in winter conditions. What’s more, they deal with heat well enough to run longer-lasting, harder-biting sintered pads for riding in the UK or upgrade to finned pads for big-mountain use.
Easy integration with shifters, pads and discs from other manufacturers
User-friendly when it comes time to bleed them
Unsurprisingly, given their price, Clarks’ M2 brakes are about as simple as they could be. The closed single-bolt clamps mean you need to remove your grips to slide them on, but we’ve found they sit alongside any shifter just fine.
The mineral oil internals are relatively easy to bleed and the callipers are compatible with Shimano pads (even finned Ice-Tech ones). Changing pads also significantly boosts the otherwise meagre power levels, but you can always upsize the rotors too.
Control and modulation are slightly wooden, but not painfully so and they’re noticeably better than anything else under £60. Reliability of the several sets we’ve used long term over the years has also been relentlessly consistent.
Performance that justifies their top-of-the-range billing
Consistent feel in all conditions
Carbon and titanium parts add bling and reduce weight
SRAM isn’t mincing words when it comes to naming its top-of-the-range Guide brake, but it’s done more than throw exotic materials at the existing unit. SRAM claims that the Guide Ultimate can cope with more braking heat than ever before and do so with a more consistent feel.
The Ultimate pistons use an alloy sleeve around a phenolic core, while tighter tolerances and a special finish mean that they receive more lubrication from the DOT brake fluid. This helps them move more freely and ensures they retract properly each time, keeping lever feel consistent. A carbon lever blade and titanium bolts are thrown in to up the bling and drop the weight. Our set weighed in at a respectable 830g for the pair including 180mm diameter ‘Centreline’ two-piece rotors.
On the trail, the first thing that struck us was the short lever throw and consistent bite-point, which allows a few millimetres of progressive and intuitive modulation. Throughout testing, the bite point and lever feel never changed.
For most, these brakes will prove more than a match for the steepest terrain, but the steepness of the price may prove more troublesome for most riders.
Before going freelance, Rob spent almost four years on staff at BBC Science Focus magazine subediting news, features and reviews. He's now a freelance journalist and has written about everything from electric cars to decomposing bodies… although space and speed are what fascinate him most.