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Trek Slash 8 Review

Words by Team Cycles

on 23/04/2021 11:11:47


A full review by Robin Weaver from

The Trek Slash 8 is our Enduro Bike of the Year for 2021. After pitting it against seven of the best out there, all at a similar price, it was the Slash 8 that impressed us most in the end.

Meeting the criteria to win this category is no easy feat and the bikes at the pointy end of this test ticked just about every box going. For a start, while an enduro bike might be designed to go downhill fast, it still needs to get to the top of the hill as efficiently as possible. It’s then got to handle all manner of trails thrown at it with composure and control, but still remain fun and playful throughout.

It took some serious time and effort back-to-back testing all eight of these bikes, which ranged in price from £3,450 to £4,198, riding them on a wide variety of trails and pummelling them relentlessly over rock and root until we found a winner.

Once the dust had settled, it was the Trek Slash 8 that had managed to edge its way into the lead. Its ability to tackle the wildest terrain without flinching yet all the while retaining that reactive, lively feel really won us over.



Travel has been upped to 160mm at the rear and is now paired with a longer travel 170mm travel fork up front. It continues to be delivered via Trek’s Active Braking Pivot (ABP) suspension system which places the chainstay pivot concentric to the rear axle.

This design, in Trek’s words, enables it to “tune how the suspension reacts to acceleration and braking forces independently”. And while this might look unchanged, Trek has moved the main pivot up slightly in a bid to increase anti-squat and make the Slash pedal more efficiently.

Controlling that 160mm of travel is the proprietary RockShox Super Deluxe Thru Shaft shock. This design features a shock shaft that goes through the damper body and exits out of the bottom of the shock when compressed.


The Slash has been, like most other enduro-style bikes in need of a makeover, stretched out, slackened and steepened in all the relevant areas. My medium frame offers a very reasonable 450mm reach, which is a massive jump of 25mm in the low setting over the 2020 model.

Trek has relaxed the head angle for improved high-speed stability and paired it with a 42mm offset fork in a bid to create the ultimate composure through rough turns. I measured the head angle at 64.1 degrees, which is now pretty much standard for bikes like this.

The seat angle has been steepened by a staggering 2 degrees in a bid to improve climbing efficiency, putting the rider’s hips more directly over the bottom bracket.

With my saddle set at just under 700mm (measured from the centre of the bottom bracket to the top of the saddle), the effective seat tube angle of the Slash 8 measured just over 76 degrees in the low setting.

The two geometry settings (low and high) are accessed via the Mino Link ovalised chips that sit inside the EVO rocker link on the seatstay pivot. Switching between the two settings alters the head and seat angles by 0.5 degrees and the bottom bracket height by a substantial 8mm.

In the low setting, I measured the bottom bracket at 344mm off the floor with a drop of 29mm, which certainly isn’t bad for a bike with this much travel.

Effective chainstay length has increased by just 2mm (now up to 437mm) compared with the 2020 model, and this remains constant across all frame sizes.

Trek Slash 8 Specifications

Let’s start with the suspension. The proprietary RockShox Super Deluxe Ultimate Thru Shaft rear shock is paired with a Lyrik Select+ fork that pumps out 170mm of travel.

While this might not be the top-tier, all singing, all dancing Lyrik, it still gets the Charger 2.1 RC damper, which allows you to finely tune both the low-speed compression and rebound damping.

A SRAM GX Eagle drivetrain offers a decently wide spread of gears, thanks to that 10-52t cassette.

Again, it’s impressive to see a drivetrain like this on a bike at this price. That said, Trek has saved a little cash by opting to use the cheaper X1 cranks with a stamped steel chainring, rather than the sleeker finished GX equivalents.


Stopping duties are taken care of by a powerful set of SRAM Code R brakes that clamp around 200mm (front)/180mm (rear) rotors. At the lever, there’s tool-free reach adjust which is handy for dialling in lever set up.

The rest of the kit on the Slash 8 comes courtesy of Trek’s in-house components brand Bontrager: bar, stem, grips, dropper post and the rather firm Arvada saddle. Bontrager also takes care of the wheels, Line Comp 30s, as well as the tyres, speccing XR5 Team Issues upfront and the lower profile and narrower XR4 Team issue at the rear.

Ride Impressions

Set up on the Slash was relatively straight forward; I set the sag at the rear to 30 per cent and didn’t add any more pressure to the shock during testing.

I did find I needed to toggle the low-speed compression dial into the ‘+’ setting on the shock to get the support I was after through high-load turns and up take-offs.

Setting the rebound took a bit of playing around with, too, but in the end, I settled on four clicks from fully closed, which left it feeling fast and active but still controlled when returning from deep in the travel.

I stuck with the single volume spacer in the Lyrik fork and added 14 clicks of low-speed compression from fully closed with 70psi in the spring. This coupled with 12 clicks of rebound damping left the fork feeling active and supple yet still composed enough when the hits came thick and fast.


Climbing Performance

The Slash felt incredibly easy-going when pointed uphill, especially considering the travel on tap and its outright intentions. This is mainly due to the easy-rolling tyres and just how stable the back end of the bike is when seated and spinning a gear. At no point did I reach down for the shock’s lever to firm things up because I never felt the need to. Instead, the Slash managed to sit relatively high in its travel and remain stable, with little in the way of suspension bob while the power was being applied.

I also appreciated the big 52t cog on the SRAM GX Eagle cassette which, after spending a long day riding lap after lap, I spent more than my fair share of time using to help preserve energy when I was really feeling fatigued but couldn’t face getting off and walking.


Descending Performance

The Slash’s super-supple suspension recovers so rapidly hit after hit, it manages to track the trail with pin-point accuracy and without sinking too low into its travel or sacrificing any of that much-loved liveliness or pop.

The support through the suspension coupled with the taut feel through the frame ensures that you can really feel a difference in speed as you pump every bump or undulation.

That reactiveness also means that getting back up to speed after tackling a slower section or awkward obstacle doesn’t feel anywhere near as laboured as it can on some super-plush big travel rigs.

Slam on the impressively punchy Code R brakes, spot your line and commit, and the Slash will soak up whatever mess lies beneath the tyres and fire you out the other side faster than you thought possible.


It’s easy to hold onto that speed too, even when things get really ugly. Here, the calm exuded by the Slash is simply incredible. While the wheels frantically bash through bump after bump beneath you, it feels as if the chassis barely flinches, isolating the rider from the worst of the feedback and remaining steadfast with no awkward pitching back or forth.

It’s this illusion of tranquillity that the Slash manages to conjure up to give you what feels like extra time to make these split-second decisions.

The Slash’s ability to hoover up the chunder with relative ease makes riding faster a whole lot easier. And that’s the whole point of these bikes, right?

Bottom Line

It took some back-to-back testing to really highlight just how impressive the Slash can be when tackling the rowdiest of terrain, but thanks to its impressive climbing manners, tidy frame details, good geometry and superb suspension, the new Trek Slash 8 has truly won me over.

While others like the Whyte G-180 might feel closer to a downhill bike in many ways, the Trek’s composure in the rough coupled with the fact that it still feels that bit more agile, poppy and playful is what helps to make this bike truly shine.

Yes, some better tyres would really help improve its performance when it comes to tackling steep, natural, muddy trails (and after switching tyres I can confirm this is the case) but factoring in the extra rubber cost at the point of purchase certainly isn’t a dealbreaker.


Overall, the Slash 8 impressed time and time again on a multitude of terrain and I was constantly in awe of the speed this thing carries through the nastiest of terrain.