See all of our Project 24.2 posts here!
Update 2:15pm: After replacing the Ti QR skewer with a steel DT RWS skewer, the squealing caused by flex in the rear end of our Project 24.2 bike is all but gone. Tight clearances don’t help, but flex in the rear end of the bike seems to have been the culprit.
While everyone (myself included) oohs and aahs over the latest and greatest range-topping gear, in order for manufacturers to provide a return on expensive R&D and pay off costly tooling it’s not uncommon to find much the same performance a step or two down the range. Though their top of the line 280g/$400 per wheel MT8 disc brakes clearly stole the show, at Interbike the guys at Magura were just as jazzed about the closely related MT6s- and offered to send a set out for our Project 24.2 build.
Coming in at 310g for a front brake with a 160mm Storm SL rotor and hardware, the MT6 saves $100 per wheel over the MT8. What’s given up for a 25% savings? The MT6 goes without the MT8’s carbon bar clamp and lever blade and a bit of caliper machining (which we’re told should make the brake a shade stiffer). The headline grabbing Carbotecture thermoplastic lever body/master cylinder remain, though. Does the MT6 perform as well on the trail as on the scale? Hit the jump for our first real-world reflections.
Molded from a combination of short and long carbon fiber in a thermoplastic resin, the MT series of brakes are an au courant flip-flop design with a radial master cylinder. As such, the T25 Easy Bleed Technology ports are duplicated on either side of the lever and both of our samples came with the same hose length attached- something that’s very nice for stocking shops. The broad aluminum lever has a nice dogleg but is more ‘blade-y’ than most I’ve used lately. It’s hardly offensive, but coming off of Shimano brakes felt a bit odd for the first couple of rides. The lever clamp bolts are actually aluminum nuts with T25 bolt heads- threaded studs are permanently installed in the lever body to prevent riders from stripping threads from the Carbotecture material. Though it’s hard to see molded into the lever body, take a close look at the torque specifications in the photo to the right. 
Reach for a torque wrench before installing or bleeding the brakes: 1Nm is not a lot of torque.
Heading south, the MT6 caliper is a skeletal single-piece forging, more piston than anything else. One of our sample calipers came with aluminum T25 mounting hardware, one with steel. Either is fine by me- the Torx looks good and most mini tools have that fitting by now. Given that the mounting bolts don’t see major loads, this doesn’t seem to me a place to fear alloy. Given that the MT6’s caliper is supposed to be a shade stiffer (and therefore provide better braking) than the MT8s’, I’ve gone with a 160/140mm rotor combination to start. The new Storm SL rotors save about 20g over the previous-generation Storm in the 160mm size (but was out of stock, so you’ll see a 160mm Storm and a 140mm Storm SL here). 
With Jagwire’s consumer hose cutter and needle driver as well as some guidance from the boys at Bikeworks, bleeding the MT6s was straightforward, making for a nice, moderately firm feel at the lever. It’s always nice to work with Magura’s Royal (because it’s blue?) Blood mineral oil- not only does it not cause cancer, but it leaves your hands feeling baby soft. Win and win. Again, remember to pay attention to the torque specifications- failure to do so could make you very, very sad. With two fingers pulling hard on the levers, it is possible to see a bit of flex in the lever body- though squeezing that hard while riding will quickly put you on your face.
After a number of hard ‘bedding in’ stops, it took a ride for the Maguras to really come into their own. Fitted to the Element MSL’s 26in wheels, the 160/140mm rotor combination is more than powerful enough for spirited riding (they have more leverage than a 180mm/160mm combination on a 29er). 
There isn’t a whole lot of daylight between the rotor and pads, which makes caliper alignment fairly important. I’m going to chalk the squealing I’ve experienced on left turns to the MT6s’ low clearance and the Roval Control Trail SL wheelset’s Ti quick release skewer. I’ve swapped the skewer out for a steel DT Swiss RWS model, which should quiet things down. Fingers crossed. I haven’t experienced any noise (squealing or gobbling) during dry or wet braking, which is very nice.
With a progressive lever feel- closer to Shimano than Formula- the MT6s have been easy to adapt to and provide more than enough modulation to keep fast tires from locking up unnecessarily. The lever throw is a bit longer than some brakes I’ve ridden lately- a feeling that some people seem to prefer and others… don’t (the $200/330g MT4s add “tool-free center-of-pressure” feel adjustment for fettlers). A recent fast singletrack ride had me alternately chasing and being chased by a strong rider, diving into corners and scrubbing speed as late as possible. Aside from that left-turn noise, I hardly gave the MT6s a thought. Which, ultimately, is the goal. Look for an update after a few rides with the stiffer skewer and more after the race…
marc
