SRAM has been busy for two years designing its first comprehensive SRAM-branded component ensemble and today we got to test ride it. XX as it is called is based around a carbon fiber double-chainring crankset and a wild-looking one-piece 10-speed cassette that spans from an 11-tooth high gear to a whopping, 36-tooth low. Eight of the ten cogs are machined from one piece of high-strength alloy steel–and then the spaces between the teeth are cut out to provide clearance for mud and debris. It was said that each cassette takes nine hours to produce. XX includes a magnesium version of the Avid Elixir disc brake and an XX-branded line of RockShox forks which use a hydraulically actuated remote lockout.
Sweet Trek Top Fuel Test sled, sporting SRAM XX.
RIDING XX
SRAM invited us to the hill country of Tuscany to ride XX for the first time. The location was perfect for the launch, because the trails there undulate through the dense woods where rocky climbs and twisting descents give riders plenty of shifting and braking opportunities. The longest climb is on par with most cross-country race courses—less than two miles, with most just long enough to entice first-time XX riders to stay in the big chainring and gut out the ascents in the big, 36-tooth cog. SRAM did the homework necessary to make every gear count—with crisp, reliable rear shifts, well-spaced ratios, and a firm-indexing sensation at the shift levers. We expected SRAM to adapt its one-lever “DoubleTap” trigger to XX, but real-time research and testing proved that a two-lever trigger was more useful—especially when shifting over rough terrain. The XX triggers are smaller than X.0 items, and require a firmer push, but the sensation is positive and shifts are instant.
 XX 2 X 10 carbon crankset
First timers (us included) will need to rethink shifting, as the steps between gears are slightly wider and more useful than a nine-cog, 27-speed system. The 28- by 42-tooth chainring combination delivers an adequate low gear to tackle steep hills and those of us who were in good form had no trouble busting out technical climbs where it was not possible to conserve momentum. After the legs got a bit soft, the sensation was akin to riding the road, where survival mode is pedaling as smoothly as possible at a lower RPM and gutting out the last third of tough climbs. Still, the XX’s selection of gear ratios and positive shifting action made it easy to forget that there was a bike underneath us and freed our concentration to focus on the gravelly singletrack ahead.
XX rear derailleur with carbon fiber cage plates and ceramic bearing pulleys
And the front changer is beefed up for right-now shifting. You'll need a ten-speed chain.
The front derailleur is road-bike fast—and that means instant up and instant down with a flick of a trigger. Because there is no middle ring, there is also no worry about where you may be in the scheme of shifting 27 gears. This alone is a reason to ride a 2 X 10, but it gets better, because the big 36 cog makes it possible to persevere after those potentially ugly moments when a rider is faced with a surprise climb and stuck in the big ring. The big-big combination is sufficiently low to be a bail-out gear and the front derailleur can easily handle the crossover—so flail away at whichever shift lever you choose and SRAM’s XX will get you up and over.
back-side view shows the intricate machining inside the 10-cog cassette
Good shifting was boosted by SRAM’s finally-got-the-balance-right disc brakes. XX brakes are strong stoppers when the lever is clamped hard, yet easy to feather over sketchy surfaces without locking the wheels. The pad material was silent and no brake rub was apparent over the two days riding in Tuscany. With the independently-adjustable shifters (the bike was set up with the Matchmaker clamping system), the triggers nested into the thumbs, while the comfortable carbon lever rarely required more than an index finger to haul the bike to a safe entry speed.
Carbon paddle and a conventional release lever for XX shift levers
While it seems that SRAM is not ready to erase the RockShox name from its XX branded forks, the XLoc system will be retained (exclusively for now) by the XX component group. The lockout is firm—even with the Motion Control feature backed out to full soft—and thus reflects the cross-country racing nature of the 2 X 10 system. Those who love lockouts will use the XLock button constantly, as it can be so easily actuated.
XLoc button extended. The gold dial on the hose-end adjusts the pedaling platform.
The XLoc remote line swivels on the fork crown and allows the hex cap to be removed without bothering the lockout hydraulics.
BOTTOM LINE?
Well, SRAM hit it right by containing XX within a useful framework—and that framework is cross-country. We think that many trailbike riders will embrace it as well as racers (who are already riding cobbed up 2 X 9 drivetrains). The 36-tooth big cog looks comical at first, but it is in use constantly and remains the key ingredient of the XX ensemble. The complete group weighs less than 2300 grams—which is a substantial advantage for a segment of cycling that watches its weight more than television. It’s a winner and we will be hearing an immediate response from competing parts makers. SRAM’s XX, however, will be tough to beat.
LOOKING AT XX: PIECE BY PIECE
The front and rear derailleurs are ground-up designs that are configured specifically for XX. So are the trigger shifters, which use SRAM’s “Exact Actuation” cable metering system that is standard fare on its Force, Red and Rival road groups. This means that the new ten-speed shifters and derailleurs are not compatible with X.0 nine-speed parts. Don’t start fretting about compatibility, however, because chain-line and cross-over design issues related to 2 X 10 forced SRAM to begin the project from scratch. We think you will agree after a walk-through of XX, that they made the correct decision.
While the rear derailleur shares much of the X.0’s geometry and mechanical specifics, the carbon/aluminum cage uses a slightly offset upper pulley pivot to allow it to cover the wider spread of the 11 x 36 cassette. SRAM makes the outer parallelogram from forged aluminum, while the inner is forged magnesium. The main pivot bolt is aluminum, and the spring and hardware are titanium. The entire rear derailleur uses T-25 Torx screw-heads, which are the same size used for disc brake rotor screws, and both pulleys use ceramic bearings to cut friction to near zero. SRAM says the XX rear changer weighs only 181 grams and had a scale on site to verify its claims.
SRAM wanted the front derailleur to shift across the entire gearing range without rubbing on the chain—and they nearly succeeded. Shifting from the smallest to largest cogs in while in the largest chainring is possible without any noise, while the granny can be cross-chained within one or two cogs without rubbing on the cage, depending upon your bike’s frame geometry. The XX front derailleur looks beefy and it is. The cage is steel and its parallelogram arms are forged aluminum. The return-spring tension is boosted to force crisp downshifts under load and there are almost 40 variations of the XX front changer available with band-clamps, direct-mount frame interfaces and in high- and low-pull cable configurations. The XX front changer is a two-chainring derailleur and in its lightest iteration, weighs 118 grams.
XX Trigger shifters are far more compact than the now-famous X.0 versions. The thumb paddle is about two thirds the size of and X.0 model and made from carbon fiber. The XX trigger retains the range adjustment of the X.0, and the two-position mount which allows riders to choose which side of the brake lever to position the shift lever clamp. The clamp itself is sold in an individual mount, or in an integrated clamp called the “Matchmaker” that fixes the shifter to the brake lever. Matchmaker clamps use a sliding threaded boss which gives the shifter pod about 30 degrees of rotation independent from the brake lever angle. Matchmaker clamps also integrate SRAM’s new X-loc remote fork lockout on either the right- or left-side brake perch. The new XX trigger shifters weigh 183 grams a pair in the remote clamping version.
The shift levers can be rotated inside the slotted Matchmaker clamp
XX cranks have been given the most attention of al the XX parts. Inside the carbon cranks and spider is a foam core and a thin aluminum skeleton. The foam core expands under heat as the carbon is heated to cure, and provided the internal pressure required to produce a sturdy carbon shell with a low resin volume. The aluminum skeleton is a long-time SRAM and Truvativ element which positions the screw and pedal locations correctly as well as providing for metal threads. There are no chainring fixing nuts on the four-bolt XX crank. Instead, the chainrings are fixed with hollow Torx screws that thread directly into the big chainring and the spider. You won’t be able to put SRAM XX chainrings on Shimano XTR crannksets because the new cranks use a different bolt circle diameter (80 millimeter by 120 millimeter).
Shifting pins and ramps keep the wide-ratio crankset shifting well. Torx screws fix the chainrings without need for nuts.
Advantages for using SRAM’s 2 X 10 system are: a better chain line (49.5 millimeters), and a slightly narrower Q-factor (the distance between pedal centers)—but the best news is that the XX crankset shifts almost instantly and weighs only 649 grams in the BB30 bottom bracket configuration.
The chainrings are available in three gear ratios—28 X 42 (the one we rode), 25 X 39 (perfect for heavier long-travel trailbikes and 29ers), and a taller 30 X 45 combination. Gearing choices are relegated to the trio that SRAM offers and cannot be interchanged. Why? Because the tooth differentials between the large and small sprockets have been selected to provide the maximum number of engagement points for shifting. Most cranksets have one or maybe two engagement points where the chain can leave one sprocket and match perfectly with the teeth on the next. SRAM’s crank geometry offers four distinct shifting ramps with profiled teeth and assistance pins—but the actual number of useful shift engagement points number up to 14. Bottom brackets spin on ceramic bearings and are available to fit BB30, BB30 press-in, conventional GXP types, and there is also a press-in GXP option.
The big 36-tooth cog dominates XX ensemble.
By far, the most eye-catching XX component is the cassette. There will be no question about your gearing when onlookers catch sight of the massive 36-tooth low cog—which is replaceable and made from 7075 alloy aluminum. The inside cog also functions as the backing plate and spline engagement for the remainder of the cassette cogs. The 11-tooth sprocket slides on separately and functions as a retaining washer like a conventional cassette. The remaining eight cogs are machined in one piece in a lattice of industrial basketry that cannot be appreciated until it is held in one’s hand for close inspection. The 11 tooth and eight-cog massif are both alloy steel and the 11 x 36 version weighs a mere 206 grams. A taller-geared 11 X 32 cassette is also available for top pros like Julien Absalon—who won the Madrid World Cup using the SRAM XX ensemble. The ten-cog XX cassette fits standard nine-speed freehubs and is compatible with Shimano-type splines.
The caliper is forged magnesium and the rotor uses an aluminum spider to save weight.
Billed as the lightest weight “fully featured” disc brake, the XX caliper, rotor assembley, hoses and fluid weigh only 291 grams. Fully Featured means that the Avid-made brake has a pad-engagement adjustment dial on the hose end of the lever, and that there is a lever-reach adjustment tucked into the base of the lever blade. The blade is made from carbon fiber and the master cylinder is much more compact than the early Elixir from which it was derived. Both the lever body and two-piece caliper are forged magnesium—a first as far as we know—and the caliper hardware is titanium. SRAM developed a stainless steel rotor which is riveted to a six-bolt aluminum carrier flange. The rotors come in 140 (rear only), 160 and 185 millimeter diameters and the sum total of the XX disc brake system is 291 grams with a 160-millimeter rotor. Only two types of brake pads are recommended for the XX system: organic and semi-metallic. This is to minimize heat buildup, as magnesium is not as good at dissipating heat as aluminum is. The brake pad backing plated are aluminum to save weight and the brake fluid is DOT 5.1 (which is a derivative of DOT 3 and 4) to handle the XX brake’s higher heat range.
Compact brake lever is made possible by switching the location of the internal return spring.
Top loading brake pads with aluminum backing plates.
XX front suspension is piggybacked upon RockShox SID, Reba and Revelation forks. All use the latest, 2010 damping systems features, with the addition of XLoc—which is a hydraulically actuated lockout system that replaces the rotating dial and cable-operated remote lockout that RockShox developed. XLoc hydraulics use standard suspension fluid and once installed, can be left untouched should the need arise to remove the right-side damper of any reason. The handlebar remote is a simple push button. Push once and it stays retracted, opening the fork. Push once more and the button disengages, locking out the front suspension. In place of the tiny crown-mounted Motion Control dial, a barrel adjuster is threaded onto the XLoc body at the hose exit which accomplishes pedal platform adjustments at a much more convenient location. The XLoc fits directly onto the brake lever clamp and is angled to engage the thumb. It is easiest-to-use remote system that we have tried to date.
 The XLoc button fits the thumb well
In case you were wondering: The SID XX World Cup fork weighs 1436 grams, the SID XX is 1546 grams, the Reba XX weighs 1651 grams (1781 in the 120-millimeter-stroke thru-axle version), and the Revelation XX is 1695 grams (1825 grams in the thru-axle version). There is no XX shock in the works—but we anticipate that it won’t be a long wait.
WHO WILL WANT SRAM XX?
Surely, cross-country racers will find XX to be the more sensible alternative to a triple chainring 3 X 9 setup. The demand at the top of the professional field is already burgeoning and those lucky enough to have early versions of XX are completely sold. Riders who own a stronger-than average pair of legs and lungs will love XX because it’s too user friendly to pass up. The new candidates for 2 X 10 are 29er riders who are now riding every hill a gear and a half taller than 26er folk. For big-wheel riders, a 26 X 39 XX crankset will put them in the sweet spot. There are many who were made for triples. Those who climb at high altitudes and less than-awesome pedalers will find that the slightly taller gearing of SRAM’s XX will toss them off of the bike on extended climbs. SRAM’s XX is beautifully executed and poignant for a large cross-section of racers and trailbike riders, but it will greatly augment the triple chainring crankset—not replace it.
SRAM XX PRICES AND OPTIONS
(just in case you wanted to know)
Derailleurs:
SRAM XX Rear Derailleur $ 2 65
SRAM XX Front Derailleur Low Clamp Top or Bottom Pull (31.8, 34.9, 38.2) $ 1 19
SRAM XX Front Derailleur High Clamp Top or Bottom Pull (31.8, 34.9, 38.2) $ 1 16
SRAM XX Front Derailleur Direct Mount Spec 1 Top or Bottom Pull (42/28, 39/26, 45/30) $ 1 06
SRAM XX Front Derailleur Direct Mount Spec 2 Top or Bottom Pull (42/28, 39/26, 45/30) $ 1 06
SRAM XX Front Derailleur Direct Mount Spec 3 Top or Bottom Pull (42/28, 39/26, 45/30) $ 1 06
Shifters:
SRAM XX Shifter Trigger Set 10 speed Rear 2 speed Index Front w/Discrete Clamp $ 2 76
SRAM XX Shifter Trigger 10 speed Rear w/Discrete Clamp $ 1 40
SRAM XX Shifter Trigger 2 speed Index Front w/Discrete Clamp $ 1 40
Cassettes
SRAM XX Cassette 11-36 10 speed $ 3 28
SRAM XX Cassette 11-32 10 speed $ 3 28
Crankset:
Truvativ XX Crank Set GXP Q156 170 or 175 BB not incl (42/28, 39/26, 45/30) $ 4 30
Truvativ XX Crank Set GXP Q166 170 or 175 BB not incl (42/28, 39/26, 45/30) $ 4 30
Truvativ XX Crank Set BB30 Q156 170 or 175 BB not incl (42/28, 39/26, 45/30) $ 4 70
Truvativ XX Crank Set BB30 Q164 170 or 175 BB not incl (42/28, 39/26, 45/30) $ 4 70
Bottom Brackets:
Truvativ BB GXP BlackBox Cups w/Ceramic Bearings English MTB $ 1 95
Truvativ BB GXP BlackBox Cups w/Ceramic Bearings with PressFit adaptor MTB $ 1 95
Truvativ BB30 Ceramic Bearing Assembly $ 1 95
Truvativ BB30 Press Fit Ceramic Bearing Assembly $ 2 05
Ten-Speed Chain:
SRAM Chain PC 1090R HollowPin 114 links PowerLock 10-speed $ 8 4
SRAM Chain PC 1090 HollowPin 114 links PowerLock 10-speed $ 7 6
XX Disc Brakes:
Avid MatchMaker X Pair $ 4 5
Avid XX 160 Front w/Left Lever Black $ 3 73
Avid XX 185 Front w/Left Lever Black $ 3 77
Avid XX 140 Rear w/Right Lever Black $ 3 73
Avid XX 160 Rear w/Right Lever Black $ 3 73
Avid XX 185 Rear w/Right Lever Black $ 3 77
XX Suspension Forks
RockShox SID XX World Cup 32mm Dual Air 100 White Motion Control XX Remote Carbon Crown/Steerer $ 1 ,120
RockShox SID XX 32mm Dual Air 100 White Motion Control XX Remote (left) $ 7 89
RockShox Reba XX 29er Dual Air 100 White Motion Control XX Remote (left) 9mm QR $ 7 54
RockShox Reba XX Dual Air 120 White Motion Control XX Remote (left) Maxle Lite $ 7 41
RockShox Reba XX Dual Air 100 White Motion Control XX Remote (left) 9mm QR $ 7 24
RockShox Revelation XX Dual Air 150 White Motion Control XX Remote (left) Maxle Lite $ 7 41
RockShox Revelation XX Dual Air 140 White Motion Control XX Remote (left) 9mm QR $ 7 24
Group price starting as low as $2430 (not including suspension)
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