Shimano SLX Review

by Brian Mullin on July 24, 2013

have been bashing, crashing and using the SLX drivetrain and brakes for the past six months on my Ibis Mojo HD,
and I have put it through the wringer, tossing it in every type of terrain
and harsh conditions, just this side of prodigious quantities of mud.
It has been brutally tough, durable, has shifted admirable, and has some
extremely powerful brakes. 

year, Shimano revamped the SLX group, and it got trickle down
technology from the XT and XTR product lineups. SLX has always been
about durability and good value, and the 2013 iteration raises the bar
for performance and value, with a retail price of $928 for the group
(sans rotors and hubs). The group gets a plethora of technical trickery
and designs, including the Ice Tech brake pads and rotors, the Shadow
Plus clutch on the rear derailleur, upgraded shifters and front
derailleur and brakes, and ‘Rider Tuned’ cranks and cassettes. The
gearing choices include a 2x of 38-24, 38-26 and 40-28, and 3x of
42-32-24, and three cassette options of 11-32, 11-34 and 11-36.

The group that I tested included the
following components:

Component Description Part # Weight Price (US MSRP)
Crankset 2×10 38-24T 175mm FC-M675 745 grams $260
Bottom Bracket Normal – w/ cranks SM-BB71-41A 88 grams $40 – w/ cranks
Brakes front 1000mm line/rear 1200mm BL and BR-M675 602 grams $140 each
Rotors 180mm – 6 bolt SM-RT66 138 grams $30 each
Cassette 11-36 CS-HG81-10) 372 grams $85
Chain Directional CN-HG74 279 grams $45
Shifters Normal clamp SL-M670 295 grams $110
Front derailleur High Direct FD-M676-D 178 grams $55
Rear derailleur Shadow Plus GS RD-M675-GS 302 grams $100

Front Derailleur
The front derailleur is available in four mounting options, High Direct
Mount (tested), Low Direct Mount, High Clamp and Low Clamp for both
3×10 and 2×10 gearing, and retail for $55. They did some minor redesign
of the derailleur, and altered the shape and profile, and tweaked the
cable routing for better frame, suspension and tire clearance, making it
‘suspension friendly’. The SLX front worked nicely, and rolled up and
down smoothly, without any stickiness, slop or clunking, giving the
usual Shimano front quality shifts.

Rear Derailleur
The rear derailleur is available in two cage lengths, the 2×10 specific
SG medium (tested) and 3×10 specific SGS long, and in Shadow Plus
(tested) and Non-Plus versions, and retail for $100 and $85
respectively. It can be used in a wide range of 10-speed gearing, with a
maximum of a 36-tooth cassette capacity. The SLX gets the second
generation of the innovative Shadow Plus, which uses a simple on/off
lever to engage the friction clutch damper system, which prevents chain
slap and derailment, and quiets and stabilizes the drivetrain. Shimano
does offer a new ‘Direct Mount’ option, which lets you remove the B2
link and attach the derailleur directly to the Direct Mount arm of the
frame, but this only works with a frame that was designed to accept this
setup, and those are currently somewhat rare.

I liked the Shadow
Plus system, and it makes a big difference in keeping everything stable
and quiet, and when hammering along extremely rough terrain it’s an
obvious improvement, though the shifting is slightly stiffer when
engaged. Even shifting under load, I never felt the rear give me any
issues, regardless of how hard I torqued and slammed the system. The
rear has performed pretty darn well, and always did what was asked of
it, even when the chain wasn’t well lubed, the tuning was slightly out
of whack, and I shifted poorly. The rear has been very durable, and has
taken a lot of abuse, getting slammed and scrapped against rock squeezes
and ledges, and the only thing it has suffered is some mild cosmetic
scratches. It might lack the precision of the XTR rear, but it’s tough,
cheap and seems to deal with ‘out of tune’ situations more ideally.

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

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

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.

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


  • 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 

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