Review: Shimano SLX Group



The cranks are available in a 2×10 version with 38-24 (tested), 38-26 and 40-28 gearing options, along with a 3×10 with 42-32-24. They come in 170 and 175mm arm lengths, with a normal bottom bracket (BB92 and BB30 adapter bearings available separately) and retail for $260. The cranks use hollow-forged aluminum arms, and the drive side has a reinforced 4-arm 64/104mm BCD spider and an integrated HollowTech-II spindle. The 2x version uses anodized aluminum outer and steel inner HG-X chainrings, while the 3x uses anodized aluminum outer, composite-reinforced steel middle and steel inner HG-X chainrings. Due to the spider design, you’ll need to choose a 3×10 crankset if you want to do a 2×10 with a bashguard.

The tough and beefy cranks weigh just a bit more than the XT model, and use stamped pins and ramps, and aren’t quite as sculptured as either XT and XTR. I never felt any flex from the arms, and the shifting was fine, though perhaps not quite as snappy smooth going from the smaller to larger chainrings as their more expensive brethren. The shiny and flat surface of the outer arms didn’t show any shoe scuff marks, which was a welcome change, and the only scratches and dings were on the arm ends, due to repeated encounters with rocks. The 38-24 gearing ratio was about perfect for steep climbs, high cadence riders, 29ers aficionados and those who like an old-school granny setup, and it worked in harmony with the 11-36 cassette. Though not as pretty as the XTR and XT cranksets, they are decently light, tough, stiff, cheap and shift just fine, even under adverse conditions and heavy loads.


The SLX cassettes are available in 11-36 (tested), 11-34 and 11-32 toothed options, and use stamped steel for the cogs, and retail for $85. The 11-36T setup has gears of 11-13-15-17-19-21-24-28-32-36, the 11-34T has 11-13-15-17-19-21-23-26-30-34, and the 11-32T has 11-12-14-16-18-20-22-25-28-32. The three largest rings are attached to a spider, and the next five are pinned together, while the last two inner ones are loose. The cassette has been very durable, and hasn’t shown any signs of premature wear, even though I torqued and loaded them hard. They don’t have the silky-smooth shift feel of XTR, but they did an admirable job. The 11-36 cassette worked ideally when combined with the 38-24 cranks, especially if you like a good granny, although you do miss the crankability at high speeds, which a 3×10 or a larger chainring would excel in. Though they aren’t light at 372 grams for the 11-36, they make up for it in robustness, durability, and price.


Not much to say about the $45 chain, as it has been tough and durable, and has shifted adequately, even though I didn’t lube it very often, and let it get immersed in rain and snow, and ground up with sand and dirt. The only oddity is that the chain is directional, and I initially installed it incorrectly the first time, and the front shifting wasn’t nearly as crisp and smooth in direct comparison.


The RapidFire-Plus shifters come in two versions, the normal clamp with removable optical gear displays (tested) and ISPEC integrated clamp, which attaches directly to brake body. The shifters comes as a front and rear pair, and includes housing and cables, and retail for $110. The front shifter has a switch on the bottom, that converts it to either a double 2x or triple 3x drivetrains, making it compatible for both systems. The ergonomic shifter’s paddles have a 2-way release trigger for thumb or finger actuation of the Dyna-Sys specific cable-pull.

The shifters performed just fine during the entire test period, and the front had a tolerable throw when tossing it up a gear, while the rear has a nice crisp click, due greatly to their Advanced Light Action shifting design. The rear could downshift one gear at a time, while upward movement could be worked in one, two or three gear shifts at once, depending on how hard, and far you pushed the paddle. I do wish the normal clamp was hinged, as it would make swap-outs easier, but that is a minor nitpick in an otherwise great shifter. I removed the optical gear display immediately, since they seem sort of superfluous to me, but some may like the reinforcement of what gear they are in.


The SLX brakes are comprised of the reservoir, and tool-free reach adjust lever with a hinged handlebar clamp, and two-piece machined caliper with oversized 22mm ceramic pistons, and IceTech pads with radiator cooling fins. They are available as a front with a 1000mm hydraulic hose or a rear with a 1200mm length, and retail for $140 each (rotors and adapters sold separately). The pre-bled system uses mineral oil, and comes with an additional olive and barb for shortening the tubing if required. I didn’t use their fancy IceTech rotors, since they aren’t available in a six bolt version for SLX, so I tested basic default steel ones.

They’re immensely powerful with the 180/180 rotor combination that I tested, and no matter how long or steep the descent was; I never felt any loss of power or suffered brake fade. They did make a subdued steel on steel noise when cranked hard, but it never seemed to cause any performance issues. Although they have plenty of power, they could feel a bit grabby, and it was difficult to feather them for technical maneuvering. It was pretty simple to bring your speed down or come to a complete stop with a good pull on the brakes, though I would have liked better modulation. The power, ServoWave mechanism and ergonomics of the lever, made one-finger usage the norm, and the brakes gave great control and confidence in any terrain. I did shorten the brake lines, which was a pretty simple task, and fortunately; they didn’t need a bleed.

Bottom Line

The 2013 SLX group has gotten a slew of technology from XT and XTR, giving the little brother of Shimano’s mountain bike group better shifting and braking. For me, the surprise of the group was the powerful brakes, which offered great control and stopping power, with fade free use, even on the longest and steepest downhill runs. The Shadow Plus rear derailleur really does tame the chain slap and noise of the drive train, and it’s a nice addition to the lineup. The ‘Rider Tuned’ cranks and cassettes offer a slew of gearing options, and I really enjoyed the 2×10 38-24 cranks with the 11-36 cassette, which greatly helped slogging up long steep climbs.

The new SLX group is quite the bargain at $928, and the powerful brakes, durability, great gearing options and good shifting, make for an excellent package. Compared to the XT and XTR groups, it’s a bit heavier, isn’t as sculptured and aesthetic pleasing, and doesn’t have the exact precision and silky smoothness during shifting.

  • Excellent value and price point – it’s cheap!
  • Powerful brakes
  • Tough and durable
  • Good shifting, especially under adverse conditions and heavy loads
  • Heavy
  • Not quite the exact precision and silky smooth shifting of XTR/XT
  • Parts aren’t as sculptured and aesthetic pleasing as XTR/XT

Overall Rating: 4 Flamin’ Chili Peppers
Value Rating: 5 Flamin’ Chili Peppers

Photo Thumbnails (click to enlarge)

About the author: Brian Mullin

Brian likes to push the limits in all the sports he obsesses in, whether it's mountain biking, whitewater kayaking, skiing, or sport climbing. He takes those same strengths and a good dose of insanity to his reviewing and writing on mountain biking products, creating technical, in-depth articles. Whenever he's not on the bike, he might be found watching MotoGP racing, otherwise look for him out on the trail.

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  • Nathan Jordan says:

    $928. That’s about $500 less than XX1. Somehow I expected the difference to be more…

    • Brian Mullin says:

      The XX1 has no front, one less shifter, and most of all, no brakes (brakes aren’t cheap in any group).

  • Jimmymats says:

    The SLX brakes are fantastic for the price. In fact, I also have the current gen XT and XTR brakes, and at least to me, there isn’t a discernable difference in performance. All 3 sets are rock solid and have immense stopping power. The market price on XTs has come down, otherwise I wouldn’t see a reason to go that route. In any case Shimano brakes seem to be a step above.

  • Loll says:

    I beg to different with Jimmymats and agrees with Brian Mullin. The SLX brakes, while strong, can use more modulation. This is important to people like me who rely on the brake to sustain a manual. Now days it is either no brake, or full brake and the front end dips. While manualling is more a showoff thing for me, it is a skill that I found harder to practice and have to rely on body balance more.

    Few years ago I demo-ed an XTR equipped bike. The brakes were so nice to feather. Again, I was using it for wheelie-ing. It was just nice as you can really modulate how light you wan to brake.

    Wonder what is the element that dictates if a brake modulates well or not?

  • nouffa says:

    In my country SLX’s being sold only US$ 460-500 complete set include rotors, and agree that it performs great

  • Matt says:

    Bare cable going into the front derailleur housing stop?

    • Brian Mullin says:

      Matt – There is a small shunt/cap wedged in the stop to keep the cable straighter.
      Doug – I regularly use the front.
      The system works fine. I was somewhat constrained by the design of the Ibis Mojo front cable stoppers/hangers.

  • Doug says:

    +1 Matt! Didn’t see that the first time I looked at the pic, but now I see it. Wonder how much that front dur was actually used (?)

  • MBR says:

    SLX always seems to be the best bang-for-the-buck grouppo. My only comment is the list of “Cons” in the review, which are really expected and logical…
    Not as light, precise, silky, sculpted, aesthetic? Let’s be honest with ourselves. Would anyone expect SLX to be better than XT or XTR and cost less?

  • Joel says:

    I think $928 is too much for an SLX groupset, Here in the Philippines 2013 XT groupset sold only for $550 to 580. 2013 SLX sold for $400 to 420 both have rotors included. Performance almost the same, its more of weight penalty.

  • mattthemuppet says:

    I love my SLX brakes. I replaced a set of Elixir 5s with them and power is a bit more, heat dissipation is waaaay better plus they haven’t had to be touched in the time I’ve had them (6mths? a year?). Compared with the Elixirs which needed constant cleaning and fiddling, plus had levers that bent if you so much as looked at them funny. I couldn’t recommend them strongly enough. 180/160 set up with standard steel rotors and finned pads (still original).

  • Recrider says:

    Just installed the new SLX FC-M672 triple crankset with 22/30/40 chainrings on my 29er. I finally have gearing close to my 26er and can use the middle ring much more. It is a very nicely made crankset and weighs only about 20g more than the XT FC-M780 triple crankset on my other bike. A very worthwhile upgrade for 29ers and makes the XT crankset pretty hard to justify.

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