First Look: 2021 Trek Slash 8 in for Review

As one of the leading bike brands, Trek continues to adhere to a model year schedule for their bike production, releasing iterative improvements every single year. Granted, some years see more improvements and changes than others, and this time it appears that the Slash has changed a ton from 2020 to 2021.

Changes to the Slash for 2021 include a new suspension layout and all-new rear shock. The new RockShox Super Deluxe Thru Shaft shock is exclusive to the Slash, and comes with a bevy of enhancements. The suspension travel also bumps up 10mm front and rear, for a total of 170mm front and 160mm rear. Stay tuned for more deets on the suspension updates in the full review.

The Slash frame now offers integrated storage in the down tube on all models, including the alloy frames. The seat tube is steeper by 1.9°, measuring 75.6° on the size medium in the low geometry position. Seatpost insertion has been increased by 45mm, and the seat tube is now designed for 34.9mm posts. New Bontrager Line Elite dropper posts come specced on Slash models, which are longer and purportedly more reliable than previous models. The reach is longer (450mm in size medium, low position), and the head tube is a degree slacker at 64.1° in the low position. As you can undoubtedly surmise, the frame features a flip-chip to adjust between high and low positions, but all testing will be conducted in the low position.

Photo: Trek

The Knock Block has also been updated to v2.0. For those who haven’t ridden a long travel Trek recently, the Knock Block is a restriction in the headset that prevents the bars, front wheel, and fork from turning completely around, to prevent the frame and cabling from being damaged. The V2.0 increases the turning radius from 58° to 72°, which they label as “more shuttle friendly” for putting over the tailgates of pickup trucks. Despite the Knock Block preventing the fork from turning all the way around, downtube clearance on the new 2021 model is also improved so that component and frame impacts don’t appear to be an issue. However, Trek notes that the Knock Block still keeps the cabling from being ripped out.

Finally, the new Slash has a “full length, dual-density downtube guard for additional protection and shuttling.”

The exact model I have in for review is the aluminum-framed Slash 8, which retails for $3,999. Even though this is a relatively affordable enduro bike, the Slash 8 features an absolute bruiser of a build kit: RockShox Lyrik Select+ fork, SRAM GX 12-speed drivetrain, SRAM Code 4-piston brakes, Bontrager Line Comp 30 wheels, a Bontrager XR5 29×2.6″ tire up front, and a Bontrager XR4 29×2.4″ tire in the rear.

Out of the box, the tires initially seemed a little flimsy for my personal riding style (especially the XR4), but so far I find that they strike a good balance. I’ve been riding the stock tires for a few weeks now, and I give Trek kudos for speccing a competent set of rubber.

Photo: Trek

The size medium Slash comes stock with a massive 820mm-wide bar, which is simply way too wide for my 5′ 7″ height. My arms are only so long! I promptly cut the bars down to 780mm, which is what I typically run.

Aside from cutting the bars and swapping in my own Ergon saddle, I’ve made no other changes to the stock build so far. I can’t say the same thing for many of the more expensive mountain bikes on salesroom floors today. I think this is a great indication that Trek’s product manager really nailed it on the Slash 8.

Stay tuned for the full analysis after my long-term beat down!