2026 Trek

X-Caliber Frameset

The Trek X-Caliber 8 is a sure-footed 29er hardtail mountain bike, with plenty of reliable elements that boost its score to impressive levels, but a few missteps that hold it back from quite making it as one of the best hardtail mountain bikes we’ve tested. There’s a whole lot to like though. Twenty nine inch wheels have long been an integral part of Trek’s mountain bikes, especially the hardtails. And where initially there was uncertainty and hesitation in the industry, Trek pushed on with this larger wheel size and the persistence paid off: with 29in wheels now accepted globally and across all mountain bike categories, not just for the cross country crowd. Trek’s early 29in wheel bikes were XC hardtails and since then, the X-Caliber has shifted upmarket and now sit between the entry-level Marlin and the carbon Pro-Caliber. All three platforms run 100mm travel forks. We’ve pulled in the X-Caliber 8 for this review, which is just shy of the Scott Scale 965 in price and shares many of the same components. With all four bikes on test running Shimano brakes and 1×12 transmissions, we were keen to take this consistency a step further and chose models with regular seatposts, rather than droppers. Primarily for comparing the weight of the bikes, but riding dynamics and overall value played a part too as we felt it really levelled the playing field, and maintained the XC hardtail design ethos. With a steeply sloping top tube and a super-low standover height the X-Caliber is a very striking bike. It’s a silhouette that’s mirrored through all the brand’s hardtails – with the notable exception of the carbon Pro-Caliber – as is the wide size range that Trek is well known for offering. Seven frame sizes are available (with the XS and S rolling on 27.5in wheels to keep proportions in check) with a useful M/L option that’s a great problem solver for riders stuck between the popular M and L options. So hats off to Trek for this level of commitment to getting a good fitting bike. When it comes to new frame standards, Trek has always been an early adopter, so it’s no surprise to see a tapered head tube and Boost hub spacing on the X-Caliber frame. But it’s Boost with a twist… here, Trek using 141mm rear dropout spacing with a traditional Q/R hub, rather than a 148mm bolt-thru design. It’s not a deal breaker though, as the fixed rear triangle of a hardtail doesn’t need stiffening up like a full suspension design, and a quick online search reveals plenty of wheel upgrade options from the likes of Hunt, Hope and Bontrager for the 141 standard. A modern touch that hasn’t been executed as well as on other bikes in test, is the internal frame routing for the cable and rear brake hose – they’re not clamped where they enter the down tube and rattle noisily on rough terrain, just like on the Trek Roscoe in our Hardtail of the …Continue reading »

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