For some odd reason, my Giant Anthem X 29er came from the factory with an SLX drivetrain, but brakes from another vendor which shall remain nameless.
The stock brakes were annoying at best, and needless to say I jumped at the chance to review SLX brakes with IceTech technology.
First, you’re probably wondering what the IceTech hype is all about. The concept is pretty simple. The pads employ an alloy heatsink not unlike what would be found on a computer processor, and the rotors are a bonded setup with a steel outer layer over an alloy core. The idea is for the alloy portion of the rotor to pull heat away from the braking surface while the heatsink quickly dissipates heat from the pads. Managing heat build-up reduces brake fade and also helps prolong the life of fluid and pads.
All Shimano hydraulic brakes come pre-bled and can be bolted right on, ready to use. The hinged lever clamp can be opened wide enough to go around the bars, but since I have clamp-on grips, I just removed the grip and slid the them on that way. My rear rotor is 160mm so I was able to bolt that caliper directly to the post mounts on my frame. With the 180mm front rotor an adapter was required.
Another installation consideration is the hose length. Rather than produce the brakes with different hose lengths for different size frames, Shimano uses one length: super-extra long. Fortunately, it is really easy to shorten the hoses with parts included with the brake set, and they don’t even need to be re-bled after! Brake line cutting/refitting kits go for $20 or so and there are plenty of how-to videos online to walk you through it. If you purchase the brakes from a local shop, they will shorten the hoses as part of the installation.
The IceTech rotors come in either 6-bolt or Shimano’s own CenterLock configuration. As would be expected, the 6-bolt model installs with a Torx drive, while the CenterLock variety uses a Shimano-compatible cassette socket. For 15mm front axles, a specific Shimano lock ring is required, as well as an external bottom bracket wrench.
Out on the Trail
The first thing you’ll notice about Shimano brakes is that all of their levers are clearly intended for single finger use. The first time you engage them you’ll see why: they have gobs of sheer stopping power! My test set took several rides for the pads to fully bed in, during which time they didn’t feel like they had much modulation but felt more like off/on. Eventually, though, they smoothed out, and now they modulate nicely but still have loads of pure stopping power when I need it.
Of course, sustained heavy braking still results in hot braking surfaces, but the IceTech features allow them to cool off noticeably faster than they would otherwise. Since installing them I have done a number of rides with long, steep downhills and I have experienced zero brake fade. (I’m a bit of a wuss on technical descents, so I use them pretty hard.)
Adjustment and Maintenance
Everything about the SLX brakes is simple. There is a single knob for reach adjustment, a single screw to let out air bubbles from the reservoir, and a single cotter pin holding the pads in place. Fingers and a basic multi-tool are all that’s required for day to day stuff. I haven’t had to bleed mine yet, but I have heard from riding buddies that they are much easier to bleed than other brands. In fact, there isn’t even a “bleed kit” per se. All you need is a bottle of Shimano or Magura mineral oil, some plastic tubing, basic hand tools and the yellow plastic caliper block that’s included with the brake set purchase. As I said, though, other than shortening the hoses, I haven’t had to do a thing to mine… they just work.
The two-piece, bi-metal rotors work great, but there is a fairly substantial weight penalty for that extra cooling. You can save a few grams by going with the non-IceTech version, but you will only get the enhanced cooling of the heatsinks on the pads. I am currently running a non-IceTech SLX rotor on the front, and I have had no issues with it.
SLX or XT
At Outerbike last fall I got to experience both SLX and XT brakes back-to-back. In braking feel, there was zero difference. The only real differences between the two model levels are the XTs’ inclusion of the “Servo Wave Power Adjuster” on the lever end, and a screw instead of cotter pin for pad retention. Of course ,the XTs are a few grams lighter, too.
I’ve quizzed a few riders who have XT and I’ve yet to get a straight answer on what the Servo Wave thingy accomplishes, and some SLX owners actually prefer the cotter pin over the threaded bolt. In my opinion, if you have the cash, go for XT, but if you’re being frugal, you can’t go wrong with SLX as they work just as well and the weight penalty is minimal at roughly 100 grams total.
With the SLX model, Shimano has brought high-performance braking to the masses. These are truly a solid performer with performance where it counts, but also concessions where needed to help keep the price down. To quote the owner of a local shop I go to, “Shimano’s brakes are truly revolutionary.”
If you’re sick of your current brakes leaking, needing to be bled all the time, or warbling like an angry turkey, then you should definitely take a look at Shimano. Go with XT or even XTR if you can afford it, or grab the eminently-capable SLX and save some greenbacks for other upgrades.
These brakes go for $266 for a front and rear set at full retail, but a little bit of searching will turn up some closeout and overstock deals for substantially less than that. The SLX IceTech rotors go for $25 – $35 depending on size, with the non-IceTech version costing about the same.
Thanks to Shimano for sending over the SLX brake set for review!