A second-generation gold medal winner

In addition to the Argent Drizzle color shown, the Supercaliber SLR 9.9 XX AXS Gen 2 is also offered in Deep Smoke and Carbon Red Smoke frame colors.


When Trek released the Supercaliber in 2019 with its integrated IsoStrut shock, the wrecking crew was impressed by its light weight and strong acceleration, calling it a full-speed-ahead cross-country race bike. It is truly a racer’s mountain bike, and this was proven multiple times at the highest levels. It won gold at the Tokyo Olympics under Jolanda Neff, and Evie Richards has won multiple World Cup races on it, too. Not one to rest on its laurels, Trek has introduced a second generation of the Supercaliber with a completely new frame with more travel and evolved features to take on the highest levels of racing.

We are happy to see traditional internal cable routing instead of the headset style that’s becoming popular.


Although it may look similar, this second-generation Supercaliber frame is entirely new. Its geometry is revised with a 10mm-longer reach, 1.5-degree-slacker head angle, half-a-degree-steeper seat-tube angle and 7mm-taller bottom bracket height in size large. The chainstay length also grows by 5mm. All of these updates combine for a 17mm-longer wheelbase than before. Our size large came in with a 67.5-degree head angle, 74.5-degree seat-tube angle and 465mm-long reach.

There are now two versions of the frame: the SLR and SL. The SLR we tested here is the lightest, coming in at a claimed 200–250 grams lighter than the current 2,030-gram version, while the SL is about the same weight. Both frames share the same new lightweight swingarm with an all-new floating brake mount that Trek says isolates braking forces from flexing rear stays for improved braking performance. SLR frames save weight by ditching the internal cable tunnels, while the SL models have them for easier cable routing. Two water bottles can fit on the frame—one on the seat tube and one on the downtube. The new Gen 2 frame has a standard headset and not the Knock Block style of the previous version.


Trek’s IsoStrut suspension design is improved on the new Supercaliber, increasing in travel and receiving an all-new RockShox SidLuxe IsoStrut. Rear-wheel travel increases from 60mm to 80mm, while the front jumps 10mm from 100mm to 110mm. Our test bike comes with RockShox’s latest SID SL Ultimate model. The frame is also compatible with 100mm and 120mm forks.

The strut’s stroke increases by 7.5mm to 40mm to gain travel, a move that Trek says does not sacrifice fitment or weight. A higher linear leverage rate is also new and ideal for XC performance, according to Trek. Sag can be set at the standard 25 percent for a good all-around feel, as low as 15 percent for more pedaling efficiency, or as high as 30 percent for added compliance. Anti-squat is also increased on the new model for better resistance to suspension compression while pedaling. The new IsoStrut is also easier to service, requiring no special tools like the old one did.


Trek offers seven models of the Supercaliber, starting at $4,200 and topping out at $11,700 for their highest-end build and our test model, the 9.9 SLR XX AXS. In addition to their lighter frames, Supercaliber SLR models are spec’d with carbon one-piece bar/stem and carbon wheels, while SL models get alloy wheels and cockpit components. Our bike came equipped with the highest-end components, such as SRAM’s stellar XX SL Eagle drivetrain, cranks and Level Ultimate brakes. We tend to pick on SRAM brakes, but they performed well on this bike.

Bontrager’s Kovee SLR wheels continue to impress us with their lightweight and excellent ride feel. As they should, because they’re the exact same wheels Trek racers have won on at the highest levels. Our test bike was supposed to be spec’d with Bontrager Sainte-Anne RSL XR tires but instead came with Pirelli’s Scorpion XC RCs.

Bontrager’s Aeolus RSL saddle proved to be incredibly comfortable, and Fox’s Transfer SL dropper post was flawless (see our review on page 92). Test riders were even pleased with the handlebar bend and orientation of the Bontrager RSL integrated bar and stem combo. Rounding out the great build is an MBA wrecking crew favorite—ESI’s Chunky silicone foam grips.


Our size-large test bike hit our scales at a rather impressive 21.8 pounds, and you really feel that on the climbs. Some of our test riders call the Supercaliber the fastest bike they have ridden, which is saying something given the recent crop of test bikes that have passed through our offices lately. It’s extremely quick on acceleration both in and out of the saddle and with the suspension open. Some even joked that it felt somewhat similar to a lightweight eMTB. They might be joking, but the sensation when you stab the pedals isn’t far off.

Seated pedaling is incredibly efficient, enough so that most riders couldn’t feel a noticeable difference between locked and unlocked suspension over smoother surfaces. It’s not until you hit a bump bigger than the tires can absorb that you really feel it work. The suspension is quiet, but moves just enough over bumps and roots to keep you planted in the saddle and driving forward. Not being able to easily feel the difference between locked out and not caught us off guard a few times, so we made it a habit to switch it off as soon as it’s not needed

The lockout is a hard one with no give to it, resulting in a fully rigid hardtail feel that we absolutely loved while hammering out of the saddle. RockShox’s grip-shift-style lockout remote makes actuation really easy and natural, so we use it more often than trigger- or lever-style ones, too. The frame is solid under power without feeling overbuilt or too rigid. It has a lively energy to it that’s stiff in all the right places while being forgiving where it can.

The Supercaliber has speed to spare on smoother courses and trails.



Descending is equally as impressive as the climbing performance. With the longer wheelbase, slacker head angle and increase in travel, we were able to get pretty aggressive on the Supercaliber. It’s still an XC race bike and reminds you of this when it runs out of travel, and the lightweight wheels flex in protest, but you can get away with a heck of a lot up until that point. The tires usually kept us from getting too carried away, but more often than not we were left more impressed with what this bike can do than what it can’t.

This is no wannabe trail bike in XC clothing. It’s a full-on racer, and a very capable one at that. The longer wheelbase really helps with straight-line stability and predictability on tough descents. Cornering on flat turns takes a touch more careful front-wheel weighting compared to steeper, shorter bikes, but we were able to adapt quickly. Our test bike came with 2.25-inch tires, which held it back some, especially on looser and more slippery trails, so we changed those out to higher-volume models, and it really helped corner feel and overall grip with little loss in climbing speed.

We initially set the suspension up with 25-percent sag, but also tried it at 30 percent, which gave it a more active feel to the beginning of the stroke. But in the end, test riders preferred the crisp and controlled feel of 25 percent. At 15 percent, the suspension feels too progressive, and we had a hard time getting the last few millimeters of travel out of it. All three settings are usable, though, so it’s worth experimenting with.


This is a long list, but here are the highlights: It’s light, it’s efficient, it’s somewhat simple, has mounts for two water bottles, and it’s very clean-looking, but most of all, it’s really, really fast. And, speed is what really matters when it comes to cross-country race bikes. The Supercaliber has that in excess.

ON THE RIDER Bontrager Circuit WaveCel helmet ($160); 100% Norvik sunglasses ($149),  Eliel Laguna Seca Performance jersey ($150), Laguna Seca Performance bib short ($180), Signature Icon socks ($15)


We wish the RockShox SID fork had more tire clearance. We would love to run 2.4-inch tires, and the frame has clearance, but technically speaking, not the fork. Although you might get away with it depending on actual tire size, we can’t recommend anything bigger than the SID’s 2.35-inch maximum. On occasion, we experienced a touch of cable rattle in the front triangle. Pushing the dropper post housing in usually fixed it, but every now and then it would return, suggesting we might need to add some protective foam to the cables.


Trek’s first version of the Supercaliber was excellent. This second generation takes it into the stellar category for cross-country race bikes. It comes at a cost, though. Even though it has more suspension travel and is more capable of managing tough descents, it’s still a sharply focused race tool.

We have ridden other cross-country race bikes that are more versatile, but few with this kind of raw speed right off the showroom floor. It’s not the ideal bike for a long pedal-heavy adventure ride. Sure, you could do it, and we did, but bikes like Trek’s Top Fuel are better suited for that and still quite quick. If you want to win races, however, look no further.


CATEGORY: Cross-country race


SUSPENSION: 110mm (front), 80mm (rear)

Price: $11,700
Weight: 21.8 pounds (without pedals)
Sizes: S, M, M/L, L (tested), XL
Frame tested: SLR OCLV Mountain carbon, 80mm travel
Shock: RockShox SidLuxe IsoStrut
Fork: RockShox SID SL Ultimate, 110mm travel
Wheelset: Bontrager Kovee RSL, OCLV Mountain carbon, 29”
Tires: Bontrager Sainte-Anne RSL XR, tubeless-ready, dual compound, Aramid bead, 220 tpi, 29×2.20”

Seatpost: Fox Transfer SL
Saddle: Aeolus RSL, carbon rails, 145mm width
Handlebar/stem: Bontrager RSL integrated handlebar/stem, OCLV Carbon, 0mm handlebar rise, 750mm width, -13 degree stem

Grips: ESI Chunky
Headset: FSA IS-2
Brakes: SRAM Level Ultimate four-piston hydraulic disc
Rotors: SRAM CenterLine X, Centerlock, round edge, 160mm f/r
Rear derailleur: SRAM XX SL Eagle AXS, T-type
Shifters: SRAM AXS Po Ultimate
Crankset: SRAM XX SL Eagle
Bottom bracket: SRAM Dub
Cassette: SRAM Eagle XS-1299, T-type, 10-52T
Chain: SRAM XX Eagle, T-type
Chainrings: 34-tooth


Head tube angle: 67.5º
Effective seat tube angle: 74.5°
Reach: 465mm (18.3”)
Stack: 599mm (23.6”)
Bottom bracket height: 327mm (12.9”)
Chainstay length: 435mm (17.1”)
Wheelbase: 1,172mm (46.1”)


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