Now, of course, in a manner of speaking, many of the rim brakes in use today are essentially "direct mount," (I would include cantilever brakes, u-brakes, v-brakes, centerpulls mounted to brazed-on studs, and single-pivot sidepulls) but what makes the new crop of dual-pivot direct-mount brakes different is that instead of having a center-mounted bolt, and having one of the pivots mounted to some type of yoke, both pivots bolt directly to the frame or fork. Some of the advantages are supposed to be better brake feel and less flex, more balanced brake movement, better aerodynamics (since the brakes can fit closer to the fork or frame), and some claim more tire clearance, though the examples I've seen so far don't seem to bear that out. Shimano offers direct-mount versions of Dura-Ace and Ultegra brakes, which are being utilized on some models by Trek, and several other manufacturers are jumping on the bandwagon.
|The two pivots bolt directly into threaded holes or bosses|
on the fork or frame. The pivots are more symmetrically
placed as compared to regular dual-pivots.
Another thing is the added complexity. From what I'm reading in reviews, some of the offerings so far are quite a bit harder to install than a typical single bolt mounted brake. I suppose that isn't a serious problem, but I haven't tried installing any yet.
With the arms fitting so much closer to the frame or fork, I've read that brake pad compatibility is also a potential issue. Unless the pads are specifically designed for these close-coupled direct-mount brakes, there can be some interference between the pads/shoes and the frame. It's always something.
|Yep -- under their face plates, these new FSA brakes are rollercams.|
My memory of rollercam brakes is that they weren't worth reviving.
The new design from FSA bears a faint resemblance to the old Delta brakes from Campagnolo -- though far less pretty. Underneath their covers, however, they work on an entirely different mechanism. Whereas the Campys had a kind of deformable parallelogram linkage, the FSAs are basically a revival of the old rollercam brakes that were briefly all the rage on mountain bikes in the 1980s. Remember those? Usually mounted under the chainstays, they would get so choked up with mud that they'd quit working, and were finicky enough to quit working even when kept clean. The rollercams also required unique mounting bosses that rendered the frame incompatible with any other kind of brakes, and therefore completely obsolete when the rollercam fad faded away. I'd be concerned about the same thing happening all over again.
Like a lot of new technology, the latest direct-mount dual-pivot brakes might offer some small, incremental improvements, but with the usual trade-offs -- the most annoying of which would have to be the all-too-common problem of compatibility (and the potential for premature obsolescence). Don't expect to hear about the trade-offs in the hype, though. Nope -- all you need to know is that the bike you bought last year is from the stone-age. Time for another upgrade.