FSA K-Force Brakes - Review

There likely isn't a harder market to jump into and be successful than the brake business. While we're often busy upgrading everything from our drivetrain to our wheels, brakes are, it seems to me, the one component on a bike that we as riders seem to get attached to and not want to change up. So what makes Full Speed Ahead think that they can take on the challenge? They explained to Pinkbike that disc brakes are really a natural extension of components that they already offer that are used to control the bike, which is true when you consider just how large of a range parts they offer. This now includes two new brakes: the somewhat economically priced Afterburners that go for $289 USD, and the high-end K-Force brakes that we review below that sell for $369 USD. Both models offer the same independent reach and free stroke adjustments, but the top tier K-Force model features a magnesium body versus the Afterburner's aluminum body, and carbon fiber lever blades, stainless steel hardware with a titanium upgrade option, and a polished finish that has them looking pretty ritzy. The front brake with a 160mm rotor and completely bled, weighs 330 grams.

K-Force Brake Details • Intended use: cross-country / trail • Carbon levers, magnesium bodies • Stainless stee hardware (Ti option) • Separate, tool-free reach and stroke adjust • Mineral oil • Stiffer hose used for rear brake • Weight: 330 grams (complete front w/ 6'' rotor) • MSRP: $369 USD

What's Up Top?

The K-Force's magnesium bodies mount to the handlebar via split perches and torx hardware, and they use an ambidextrous design that allows each brake to be mounted on either the left or ride side of the bar. The carbon fiber lever blades, which pivot on bushings rather than bearings to drop a handful of grams, are quite long compared to what you see on the competition, and this should make them compatible with both Shimano and SRAM shifters, including Grip Shift. Adjustments include tool-free and independent reach and free-stroke, with the former sitting out of harm's way behind the lever blade and the latter tucked up nearly flush into the front of the body. FSA had planned to use titanium hardware for choice fasteners but instead have gone with stainless steel for the production version of the brake, likely for cost reasons, although a titanium upgrade option is available should K-Force owners want to go that route. There are also a few details that aren't as obvious to the eye, including the slightly stiffer hose used for the rear brake line that FSA says helps to create a more even brake feel when comparing front and rear modulation. This is done by using a slightly stiffer plastic inner liner, as well as a different sheath layup for the middle layer in contrast to the front brake line.







Caliper and Rotor

The one-piece caliper looks like it's been pared down to only the bare minimum, and inside are two 22mm pistons that move FSA's semi-metallic brake pads with alloy backing plates. The pads are top loading to make swapping a new set in easy, with a threaded aluminum pin and safety clip holding them and the pad spring in place within the caliper, and I'm sure that a lot of riders will be happy to hear that the calipers accept standard Shimano pads rather than a proprietary design. That means that you won't ever have a hard time finding replacement pads when you need them, and you can even fit a set of the fancy Shimano Ice Tech pads if you choose to. Just like pretty much everything on the market these days, the caliper is a post mount design that should make centering it properly over the rotor an easy task, and the outboard banjo bolt can be loosened to position the hose at an angle that makes sense for the frame or fork that it's mounted to.



The K-Force brakes come with smart looking two-piece rotors that feature aluminum spiders, although our test model is pictured here with a 180mm one-piece rotor from the less expensive Afterburner model. The idea of the two-piece design to improve heat management and create a stiffer rotor, and FSA has included some subtle details like countersunk rotor mounting holes and a milled away backside to the aluminum carrier, both of which make for a very nice looking setup.

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Setup and Ergonomics - It's a given that any high-end brake worth using should offer at least some sort of tool-free reach and stroke adjust, and the K-Force ticks both of those boxes. The more important factors are how effective each of those adjustments are, how detached from each other they are (does dialling in the lever position a bit have it hitting the grip by the time the pads bite?), and if either of them migrate during extended use. The K-Forces do well on all accounts except for some lever migration over time, with them moving out on their own slightly over a dozen or so rides. This isn't a deal breaker - it's something that I find happens from Shimano and Avid as well - and it takes a second or two to get them back to where they belong by using the red aluminum dial behind each lever blade. The range for both reach and stroke adjust are wide enough to keep everyone from a five year old girl to Andre the Giant (R.I.P.) happy, so any rider out there should be able to set them up to their liking. And on the topic of turning dials, I'm a fan of how protected both the reach and stroke adjust dials are, but the stroke dial on one of the brakes seized up after a month of use and has refused to turn since. Not even a big set of pliers is enough to coax it free. No issues on the compatibility front, with the brakes playing nice with Shimano and SRAM shifters.



Power - More power is more better, right? That depends, because useable power is more important than having a set of brakes that feel like someone stuck a golf club through your spokes every time you pull the lever, but not having enough power is certainly not a confidence inspiring thing, either. FSA is clear that the K-Force brakes aren't meant to be brutes in the power department, with their intentions leaning more towards cross-country riding and racing, but I found that they were a little down on power for my liking even when used in a pure cross-country race setting. Back-to-back rides on the K-Forces and two piston offerings from both Shimano and Avid proved that the FSA stoppers require more effort from the hands to get the same result at the caliper, enough so that descents lasting more than five minutes and required a lot of brake left me with tired paws. Granted, a lot of the trails I frequent are steeper, rougher and sometimes faster than what you'd find on a typical cross-country race course, but I've also ridden other two piston brakes designed for cross-country use that didn't leave me asking for more. FSA explains that it all comes down to the pad compounds that they've decided to go with for the K-Force, and that using a more aggressive aftermarket option can bump up the power over what the stock setup has. ''you are on the money with how friction material or pads can affect the progressive feel of a brake, making it too grabby in some cases,'' Richardson explained. ''That said, we set a performance target for these brakes when we developed the friction material that is aimed at cross-country to trail usage. You can most certainly find a number of pads that will improve power characteristics compared to our spec pad, but they will most likely perform worst in multiple other areas.'' What other areas is Richardson referring to? Burnishing, both low and high speed coefficient of friction, wet performance and wear rate, sensitivity to pressure and heat, as well as noise and vibration. And while there is a lack of outright stopping power, the K-Force brakes do score high in all of those other categories.

My advice would be to go one size up on the rotors that you'd usually run if you fancy yourself as being a little more aggressive than your average cross-country racer, even if that's exactly the intentions that you plan on using the K-Force brakes for.



Modulation - It's a shame that a lot of riders judge brakes solely on the amount of power they offer, especially for FSA, because modulation is really the more important factor for anyone who's riding on a regular basis and who values control at the levers. And that's exactly what the K-Force brakes serve up, oodles and oodles of modulation that didn't just have them feeling like the calipers were connected to my brain, but that the two were like an old couple who had been married for fifty years and can finish each other's sentences. Loose conditions that resemble what it must be like to ride in Iraq in the summer really allowed the K-Forces to shine, and it was like you could sense a lock up coming and have plenty of time to back off slightly. The same goes for when riding in the mud, and anyone who finds themselves spending a lot of saddle time in either sort of challenging environments will be doing themselves a favour by using the K-Forces. All that said, the lack of outright stopping power does likely play a role in how much modulation the FSAs seem to have, and I do believe that more bite would likely equal a bit less control.

While the lack of power probably plays a role, the amount of control on tap really is next-level, and FSA has, at least in my mind, stole the title of the best modulating brakes away from Magura with their new stoppers.





www.fullspeedahead.com

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