Vital Test Sessions - Trek Slash 9.9 X0 AXS T-Type 13

The ground up redesign featuring a high-pivot suspension design, more travel, and loads of adjustability make this Trek's most adaptable Slash yet.

Trek has a long history of taking a unique approach to frame construction, suspension platforms, and just about any bicycle component. Having created some of the first carbon fiber frames in the mid-80s and developed a handful of wild suspension technologies over the last 15 years, they are familiar with doing things differently. They are also familiar with success in racing and in just about every discipline.

They've figured out what works, and their frame designs have settled into the more conservative category in recent years, generally mimicking one another across all categories. Stepping away from the traditional frame design of its predecessor, the latest Slash mimics the longer travel Session downhill bike, moving the needle forward in the pursuit of maximizing descending performance and adjustability. 


  • 29/27.5-inch wheels
  • 170mm (6.7-inches) rear travel // 170mm (6.7-inches) fork travel
  • Full carbon frame construction 
  • 63.3 degree adjustable head tube angle 
  • 76.7 degree size specific seat tube angle
  • 513mm reach (size XL)
  • 439.2mm size-specific chainstay length
  • High pivot suspension with idler
  • 19t chain idler
  • Active Braking Pivot for fully active suspension under braking
  • Internal cable routing
  • Internal downtube frame storage
  • Bolt-on downtube protection in multiple locations
  • Molded chainstay protection
  • Integrated rear fender
  • 12x148mm Boost rear hub spacing
  • SRAM UDH and T-Type compatibility 
  • 73mm BSA threaded bottom bracket with ISCG05 tabs
  • MSRP: $9,499 USD as tested (9.9 AXS XO T-Type)



  • Highly adaptable geometry settings and geometry
  • Confidence inspiring in the most aggressive terrain
  • Doesn't bob under pedaling but remains active
  • Maintains control under heavy braking 
  • Multiple dropped chains
  • Integrated tool rattles inside steer tube
  • Requires more effort to generate speed on mellow terrain


The sixth-generation Trek Slash is undoubtedly a head-turner. From the one-piece bar/stem combo to its multi-idler chain routing, this bike is littered with tech from head to toe. As always, the Slash focuses on the gnarliest of terrain, and the newest iteration takes things a step further with a 170mm high pivot mixed-wheel platform. Adaptability is the name of the game with the frame. Virtually everything is adjustable, from the head tube angle to the leverage rate of the rear suspension, along with rear-wheel sizes via interchangeable lower shock mounts. Pivot bolts appear easily serviceable and well tucked away from dirt and grime, partially thanks to the integrated rear fender.  

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Our 9.9 X0 AXS T-Type build kit came littered with all the best from SRAM, just short of the XX-level components, but functionally offered the same level of performance. This build kit includes a RockShox AXS Reverb seatpost with a max travel option of 170mm. Once upon a time, 170mm droppers were the longest available option and not an issue, but with seat tube angles becoming steeper year after year, two out of three testers had an issue with it getting in the way unless the post was slammed. The Bluetooth kit is nice, but something with more travel would be appreciated for larger frame sizes. 

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To address the obvious elephant in the room, most people who have gotten their hands on the first run of the new Slash have experienced dropping chains regularly. A concerning issue that is hard to imagine happening with the level of chain retention around the chainring; thankfully, Trek has a solution. Both MRP, who makes the lower idler guide, and Trek informed us that the first run of bikes was assembled with 2mm less spacing than required to align the lower guide to the chainring. We experienced the chain jumping over the outside edge of the lower guide, and this solution seems to solve that problem by moving that edge further outboard. We'll be giving this a try to see if it resolves the issue and update this article should the issue continue. Still, for now, it seems to be an easy solution to an otherwise daunting problem so early in a new product cycle. 

Screenshot 2023-11-07 at 12.20.39 PM


Much of the comfort we felt on the Slash came from the rear suspension and very central weight distribution, but it also came from the confidence-inspiring geometry. The 513mm reach on the size XL is certainly roomy and did create a slightly forward position on the bike, but the slack 63.3-degree head tube angle put the front wheel in a comfortable place to lean into. Swapping to a taller bar helped put our body weight more in the middle of the bike and allowed us to get over the rear, but this did cause us to give up a bit of front-wheel traction. This was solved by swapping to a 50mm stem to balance things out. As mentioned, the rearward axle path does result in a bit of energy loss when pumping and jumping, but that was the only scenario where we noticed the rear-center growing. 

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On the Trail

Pointed downhill, the Slash glued our feet to the pedals and let us run over almost anything. The playful nature of the 27.5 rear wheel is somewhat lost in the rearward axle path when unweighting or popping off of side hits, but so is the feeling of hanging up on square edges that generally comes with a smaller rear wheel. These characteristics balance each other out; what we couldn't unweight or jump over, the Slash had no issue running over. The rear suspension performance is a strong point, without a doubt, although we experienced a bit of spike from the RockShox Vivid rear shock that could require some air can volume adjustment to resolve. 

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Trek's Active Braking Pivot, which pivots around the rear axle, helps maintain traction while under heavy braking and was appreciated when things got hectic. That active feeling also carries over when things are less exciting while pointed uphill. We were just as impressed by the rear suspension performance while climbing. Two standout characteristics were the small bump sensitivity while pedaling and the lack of pedal bob while doing so. The Slash does an incredible job of balancing a high anti-squat value with a leverage curve that removes trail chatter from each pedal stroke. It's no rocket uphill, but it is very impressive how well it carries its weight and travel uphill. 

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What's The Bottom Line?

Our test crew all thought the Slash felt best in the gnarliest terrain and was less exciting on jump trails. It may not be the best all-around bike for the most variety of terrain, but it is one of the best for double black diamond trails. If you find yourself riding less aggressive terrain with a bit more of everything, the Gen 5 Slash is still available from Trek and may be the better option. If your everyday ride looks more like downhill bike terrain without a chairlift or a shuttle involved, the Gen 6 Slash will be right at home. 

We stayed right at the base of the mountain, courtesy of Visit Big Bear, and couldn't have asked for a more convenient way to spend the week testing bikes. With our condo less than a minute from the Snow Summit village, we could easily head back to our unit between laps to swap bikes and had plenty of space to work on our bikes. Off the bike, we were thankful to have enough room for our whole test crew, as well as a pool and hot tub within walking distance to relax after each day's testing. Big Bear has a wide variety of food options and a great downtown we explored when looking to mix up our dinner plans or just grab some ice cream afterward. If you'd like to explore Snow Summit or Big Bear, California for yourself, visit or for more information.​

Big thanks to those who sponsored this test and made our trip possible!

Head here to check out the entire 2023 Enduro Test Session Feature

Learn more about the Trek Slash at

View key specs, compare bikes, and rate the new Trek Slash in the Vital MTB Product Guide.


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