Mountain Bike Action Bike Test: Trek Supercaliber 9.9

Supercaliber 9.9

Developed by Trek engineers over three years, the Supercaliber made its first stealth-like appearance in 2019 at the Nove Mesto UCI World Cup race with top riders Jolanda Neff and Emily Batty pushing the design of the bike to its limits. While spectators watched that weekend’s race, the design was still under development and literally covered up on the frames that the riders were testing. At the time, it left viewers asking, “Is it a hardtail? Wait, is there a shock under the cover?” The cat has since been let out of the bag to reveal Trek’s latest suspension design known as the IsoStrut shock. Fast-forward to the present, and the Supercaliber is no longer exclusive to World Cup athletes.


Without the sneaky wrapping paper, the Supercaliber was designed to achieve the best riding traits of both a hardtail and a full-suspension cross-country bike. The Supercaliber has several build options that range from $5,899 to the jaw-dropping price of $11,499. We were fortunate to have our test riders on one of the higher-end Supercaliber 9.9s with a retail price listed at $9,499. When your races consist of grueling climbs or photo-finish sprints, you’ll be glad to put down the hammer with a helpful low stack height that puts the rider over the front of the full OCLV carbon frame.

This lightweight carbon frame also features Trek’s Control Freak internal routing to keep the cable housing quiet, a Knock Block headset, Boost spacing in the rear, room for two water bottles, a tapered head tube, and 60mm of travel with the IsoStrut design.


The defining feature of the Supercaliber is the exclusive IsoStrut shock. It is a structural suspension that pairs 60mm of travel with a pivotless seat stay design.

All gold everything! The Trek Supercaliber 9.9 is decked out with all the top-of-the-line options an XC rider could ask for. The 9.9 we tested is the SRAM XX1 build, but Trek also offers an XTR option for the same price if you prefer Shimano. Furthermore, our test build could be brought to a standstill with SRAM Level Ultimate hydraulic disc brakes that brag about being equipped with lightweight carbon levers. To maneuver this XC machine, Trek equipped the bike with a narrow 720mm Bontrager Kovee XXX carbon bar mounted to a Bontrager Kovee Pro stem made from alloy. Sticking this very lightweight rig to the ground is a set of tubeless-ready 2.20-inch Bontrager XR1 tires. These tires are set tubeless with Bontrager TLR sealant onto Bontrager’s Kovee XXX 30 OCLV carbon wheelset.


Unlike other full-suspension bikes, the IsoStrut was made to be a structural part of the frame. This eliminates the extra hardware and weight usually associated with full-suspension bike designs.

The minimal design of the rear suspension is where the unique aspects of the Supercaliber shine through. The proprietary IsoStrut suspension provides 60mm of total travel. Whereas most suspension has an independent shock and linkage system, Trek’s design has the shock as a structural part of the Supercaliber’s frame. The proprietary Fox shock mounts just in front of the strut, where an anti-rotational pin is set to prevent twisting within the strut. To steer away from excess lateral movement, the builders completely left out the option of a rear pivot. Instead, the flat carbon seatstays bow about 3mm to 5mm vertically. Note that the shock offers 55mm of travel, while the flex in the stays equals out to 60mm.

This is how Trek bridged the gap between a stiff pedaling hardtail and a terrain-ready full-suspension race bike. At the front of the Supercaliber, Trek also spared no expense on this build and equipped it with a lightweight 100mm Fox Factory 32 Step-Cast fork. With our test riders eager to clip in and put Trek engineering to the test we set off for the dirt.

With a flick, the lightweight carbon frame can easily boost into the air while the Knock Block headset prevents frame damage from spinning handlebars or fork crowns.


The Supercaliber screams for the cross-country-racing rider. We don’t recommend this bike as an option for the “sendy” trail rider, but in capable hands, the Supercaliber can tackle some tremendously technical terrain. The reduction of weight with the IsoStrut design and carbon components will…

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