Key Test Sessions – Trek Slash 9.9 X0 AXS T-Type – Mountain Bike Function

Trek has long taken a unique approach to frame construction, suspension platforms and nearly all bicycle components. Having developed some of the first carbon fiber frames in the mid-80s and developing a handful of wild suspension technologies over the last 15 years, they’re no stranger to doing things differently. They are also aware of successes in racing and in almost all disciplines.

They’ve figured out what works and their frame designs have been in the more conservative category in recent years and are generally similar across all categories. The latest Slash deviates from its predecessor’s traditional frame design, mimicking the session downhill bike with longer travel and moving the needle forward to maximize downhill performance and adjustability.

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Highlights

• 29/27.5 inch wheels
• 170 mm (6.7 inches) rear travel // 170 mm (6.7 inches) fork travel
• Full carbon frame construction
• 63.3 degree adjustable head tube angle
• 76.7 degree size-specific seat tube angle
• 513 mm reach (size XL)
• 439.2mm size specific chainstay length
• High swivel suspension with tension roller
• 19t chain tension roller
• Active Braking Pivot for fully active suspension when braking
• Internal cable routing
• Internal downtube frame storage
• Down tube protection screwed on in several places
• Molded chainstay guard
• Integrated rear fender
• 12 x 148mm Boost rear hub spacing
• SRAM UDH and T-Type compatibility
• 73mm bottom bracket with BSA thread and ISCG05 tabs
• MSRP: $9,499 as tested (9.9 AXS XO T-Type)

overview

The sixth generation Trek Slash is undoubtedly a looker. From the one-piece handlebar and stem combination to the multi-pulley chain guide, this bike is packed with technology from head to toe. As always, the Slash focuses on the most difficult terrain, and the latest version takes it a step further with a 170mm high mixed wheel pivot platform. The frame is all about adaptability. Virtually everything is adjustable, from head tube angle to rear suspension leverage to rear wheel sizes via replaceable lower shock mounts. The pivot pins appear to be easy to maintain and well protected from dirt and grime, thanks in part to the integrated rear fender.

Our Kit 9.9 This kit includes a RockShox AXS Reverb seatpost with a maximum travel option of 170mm. There was once a time when 170mm telescopes were the longest option available and weren’t a problem, but as seat tube angles got steeper every year, two out of three testers had the problem of them getting in the way because the seat post was slammed. The Bluetooth kit is nice, but something with more travel would be desirable for larger frame sizes.

To address the obvious elephant in the room, most people who got their hands on the first version of the new Slash experienced chains falling on a regular basis. A worrying problem that is hard to imagine occurring with the chain retention around the chainring; Luckily, Trek has a solution. Both MRP, which makes the lower linkage guide, and Trek told us that the first bikes were assembled with 2mm less clearance than was required to align the lower guide with the chainring. We have experienced the chain jumping over the outside edge of the bottom guide and this solution seems to solve that problem by moving that edge further out. We will try this to see if this resolves the issue and will update this article if the issue persists. Still, for now, it seems like a simple solution to an otherwise formidable problem so early in a new product cycle.

geometry

The comfort we felt with the Slash was mainly due to the rear suspension and the very central weight distribution, but also to the confidence-inspiring geometry. The 513mm reach on the XL size is certainly roomy and provides a slightly forward position on the bike, but the slack 63.3 degree head tube angle means the front wheel can lean comfortably. By switching to higher handlebars we were able to shift our body weight more towards the middle of the bike and were able to get over the rear, although this meant we lost some traction on the front wheel. This problem was solved by switching to a 50mm stem to compensate for the problem. As mentioned, the rear axle’s path results in a slight loss of energy when pumping and jumping, but that was the only scenario where we noticed rear center gain.

On the path

Downhill, the Slash glued our feet to the pedals and caused us to run over almost everything. The playful nature of the 27.5 rear wheel is somewhat lost in the way it moves backwards when it comes to weight relief or bouncing off side hits, but also the feeling of getting caught on square edges that usually comes with a smaller rear wheel. These characteristics balance each other out; What we couldn’t unload or jump over, the Slash could easily run over. The rear suspension performance is undoubtedly a plus point, although we did experience a slight spike in the RockShox Vivid rear shock that may require adjusting the air chamber volume to resolve the issue.

Trek’s Active Braking Pivot, which rotates around the rear axle, helps maintain traction even under hard braking and was appreciated when things got hectic. This active feeling carries over even when things get less exciting uphill. We were equally impressed with the rear suspension’s climbing performance. Two outstanding features were the sensitivity to small impacts when pedaling and the lack of pedal rocking. The Slash does an incredible job of balancing high anti-squat with a leverage curve that eliminates trail chatter with every pedal stroke. It’s not a rocket uphill, but it’s very impressive how well it supports its weight and goes uphill.

What is the end result?

Our testing team felt the Slash felt best on the most difficult terrain and was less exciting on jump paths. It may not be the best all-around bike for a variety of terrain, but it is one of the best for double black diamond trails. If you ride less aggressive terrain with a little more of everything, the Gen 5 Slash is still available from Trek and may be a better option. If your everyday ride looks more like downhill bike terrain without a chairlift or shuttle, the Gen 6 Slash is for you.

Click here to watch the whole thing Enduro test session feature 2023

Find out more about the Trek Slash at trekbikes.com