2021 Trek Slash 9.8 First Ride Review

Lester Perry | Fri 4th Sep 2020 03:00

The 2021 Trek Slash 9.8 is a beast of an Enduro bike. Built to handle big hits, rail corners and reach podiums on race day. Evo was lucky enough to get our hands on one of these long travel 29ers before global release and put some hours in on the trail. Here's our initial ride review, the hype is real!

2021 Trek Slash 9.8 Ride Review:

With today’s launch of the 2021 Trek Slash 9.8, we can finally pull back the curtain on this beast we’ve been lucky enough to have in the stable for the last month.

She’s a good looker, the pop of the Orange contrasts with the ‘brushed chrome’ Trek logo.

Trek Slash History:

The Slash was initially launched as a 26” wheeled, 160mm travel bike way back in 2012, the platform has been through a few iterations since, moving with the market and adjusting to suit the times. The most recent, and completely redesigned Slash frame was launched 4 years ago, complete with its bigger 29-inch hoops and shorter travel (150mm) and revised suspension design. The bike was developed specifically for the ‘Trek Factory Racing Enduro’ team who at the time were favouring the then very popular, Remedy 29” bike (140mm travel) opposed to its heavier hitting (160mm travel) but smaller wheeled (27.5”) brethren in the Slash. Immediately the new 29er Slash became a favourite for big-mountain trail riders, enduro racers, and bike park lappers. For the first two seasons, the bike was only available in 3 sizes (S, L, XL) and only in Carbon, pretty limiting for how much demand there was for it. Fortunately, in 2019 the brand launched an affordable alloy version, with an extra size, and a sneaky update to its geometry, the reach stretched 8 mm longer, and the seat tube angle was 0.8° steeper, however, the carbon model remained the same…. Until now!

The original, 2012 Trek Slash
The 2020 Trek Slash

For 2021 Trek’s engineers went back to the drawing board, a lot has changed in the Enduro world in the last 4 years so they needed to make some big changes in order to have a competitive bike. EWS race stages are no longer won or lost on brutal 1 min+ climbs as they often were back in the early days, and while the 2017 Slash was certainly angled toward descending, it didn't go the whole hog. These days courses are much gnarlier, with higher speeds and bigger consequences, requiring more from the bike than ever before.

Trek Slash - The Bike:

If you’re looking at a side view of this bike it looks pretty similar to the previous one, but compare them side by side in the flesh and it’s obvious there’s a tonne of change that’s taken place. Everything is on steroids compared to the first iteration of the frame, every tube has been scaled up, and overall the bike is much beefier in appearance. The front end has had significant changes, with the tubes now even larger than before, allowing for the BITS box (in-frame storage under the bottle-cage) and the head tube area resembles a more traditional bike with its lack of ‘Straight Shot Downtube’ featured on the old bike (more on this below).

Trek's new BITS downtube storage
Visually the new Knock-Block 2 is the same as previous version

A fearsome-looking bike needs fearsome-looking parts and the RockShox ZEB ticks that box on the front end with its 38mm stanchions and 170mm travel, the other notable “upsize” is the 34.9mm sized dropper post. The larger post is stiffer than the 30.9mm version from last year, this is noticeable while climbing in the saddle and the larger bushings and redesigned internals mean the post should last longer and require less servicing. The “free play” is drastically reduced over the previous version too, besides the performance advantages, any smaller post would be dwarfed by the rest of the bike.

The 2021 Slash has a commanding presence
The new seatpost is a 34.9mm size

It’s no secret the first iteration of the Knock-Block steering stopper annoyed some people, but the reality is it didn’t really hamper your riding and generally did its job of stopping your fork crown hitting the Straight-Shot Downtube. Thanks to Knock-Block 2 you can now do full radius turns and use the stopper to prevent the cables from tangling up or pulling out of your levers - good for crashing. Alternatively, you can remove the entire contraption and operate 100% as normal. The obvious visual change here is the lack of Straight Shot Downtube, the reason Knock-Block came about in the first place. Most of the Trek MTB range still has Straight-Shot (and KnockBlock), which in theory, enables them to pare back the weight while keeping the front end torsionally stiff.

The bike rolls out on new ‘Line Elite 30’ wheels which appear to be more forgiving than the previous model but still stiff and snappy to ride. Having ridden the previous versions we found them overly stiff and harsh to ride, transmitting too much trail feedback to the rider, these new ones are much smoother and more comfortable. The Line Elite wheels bat way above their pay-grade and the rear hub has exceptional (for OEM) engagement and the Warranty is top-notch.

The RockShox ZEB Select fork is also new for this season. The ZEB is undeniably stiff and there’s no noticeable deflection or wandering when ploughing through the chunder. It’s plush off the top and is plenty sensitive enough, although we would like to experiment with some additional volume reducing tokens in the air-chamber to see if we could get it to sit up a bit more in its travel while running comparatively low pressure.

The rear suspension on this new bike is good, like really good. The previous model shock employed ‘Reaktive’ technology which helped the old model Slash to pedal well, even with its very linear suspension rate, the issue with this was you lost a lot of the small bump sensitivity. Thankfully Trek has ditched Reaktiv from the Slash & Remedy models for 2021. No Reaktiv now means the bike is far plusher off the top than the old version, meaning much improved small bump sensitivity, increased traction in all conditions, and less feedback to the rider. Couple the lack of Reaktiv with Trek’s unique Thru-Shaft technology and you get a shock that is super active and gets out of the way of bumps quickly, again helping it feel impressively smooth. Along with the new shock, the bike gets completely new suspension kinematics, it ramps up nicely as it goes through the last half of its travel, meaning no harsh bottom out, something which was evident on the old bike. The new suspension curve also gives the rider good support to “push” against while ripping turns and helps keep it feeling relatively playful while charging down trails. The shock features a 2 position lockout - Open or Firm. The firm setting is great and sits the bike up at full extension, aiding hugely in the bikes climbing ability. While in the ‘Open’ mode there are 3 compression settings on offer, although these seem to have only a small noticeable effect.

A new shock and revised kinematics makes the Slash super plush.

The bike is supplied with Bontrager (Trek house brand) tyres, the SE5 upfront and an SE4 on the rear, and while these stock tyres are fast-rolling and great in dry conditions, a bike like this deserves gruntier meats to get the most out of it, and the knobs are too low by today’s standards. This tyre combo is perfect for a trail bike but limiting when it comes to the bike's intended purpose.

Bontragers SE range of tyres are great in selected conditions and the SE (Super Enduro) sidewall effectively wards off punctures. 

The drivetrain on the Slash 9.8 is hard to beat. We’ve raved about Shimano’s new 12 speed XT before, and once again it’s not let us down. New to us are the SLX brakes, but with a blindfold on you’d be hard-pressed to tell them apart from the XT version. The only weak point on the supplied brakes we can find is the basic rotors, which we expect would heat up and cause brake fade on long descents but on shorter descents proved to be surprisingly powerful.

Shimano Deore XT, 12 Speed, 10-51T Cassette
Shimano’s XT drivetrain is a solid performer

Some subtle additions feature on the frame itself, including the bolt-on downtube armour. This year armour runs from up by the head tube all the way down under the bottom bracket, keeping your frame safe from rock strikes and shuttle rash. A welcome change is also the cable routing, with cables entering the frame as usual by the headtube, but this year exiting the frame just above the bottom bracket and instead of being internally routed to the brake calliper and derailleur the cables are nicely routed externally along the chainstay. If you’ve ever tried routing cables through the back end of the previous Slash frame you’ll be very happy to see this change!

What about that hold in the downtube you say? Well, the BITS box is a good addition, but in all honestly the bike would be fine without it. It’s a nice touch and a good place to stash a spare tube, CO2 canister and tyre lever, but the reality is you can't fit much else in here, and we’re not sold on the bottle cage that comes attached to it, time will tell how this holds a bottle when the going gets rough.

Full length, bolt on downtube armour keeps the frame safe from impacts

Trek Slash - The Ride:

Riding this bike reminded us of our first ride aboard a modern downhill bike - pick the most ridiculous and rough line you can find and let go of the brakes, the bike will see you through.

It’s fair to say the ride is truly the sum of all its parts - It's great throwing a stiff fork on a bike, but if the frame itself isn't stiff enough, the fork won't be able to do its job properly, with the ‘softer’ frame allowing the front wheel to deflect off obstacles regardless of how stiff the fork is. Trek has knocked it out of the park with this bike, the fork stiffness mates well to the frame stiffness, and when thrown into a rough section there’s no noticeable deflection or torsional flex through the frame, the bike calmly maintains its course smoothly below you.

A true highlight of the bike is the rear end, the new rear shock and updated kinematics make this bike super plush. The back wheel really does get out of the way of bumps exceptionally fast and helps to keep the bike quiet. Small bumps are dealt with much better than the old model and overall rear wheel traction is increased, particularly across rough off-camber, again thanks to its supple suspension. Out of the saddle sprinting is rewarded in forward momentum, not frame flex, and nailing technical sections while climbing out of the saddle is simple thanks to the stout frame and supple suspension keeping the power to the ground and bike on course.

The steeper seat-tube angle (75.6 deg.) and longer reach (486mm) puts you in a nice comfortable position for seated climbing, although it would have been nice to see Trek go a little more progressive in these departments, steepening things up a degree or two more, and lengthening a few more mm, Trek has done what they typically do and remain somewhat conservative when it comes to geometry.

Compared to the previous Slash this new beast carries speed better, changes direction better, and climbs better, and well, does everything better really. The only real drawback from the previous bike is a gnat’s hair of extra weight, and when in the ‘Open’ setting on the shock, the lack of Reaktive in the rear shock makes pedalling around or “pumping” on mellow trails more of a chore, that's not really what this bike is for though right?

All this plushness and ‘plough-ability’ comes at a bit of a tradeoff though as you lose a bit of playfulness and pop, but you make up for it in high-speed capability. That's what this bike is really all about, the highest average speed from top to bottom of a run, jumps are just a bonus!

Shop Trek Slash

Riders / Reviewers:

Matt Berry, 19

An EVO ambassador for the last few years, Matt’s been riding and racing every type of bike since he was born and has gained a wealth of bike experience far beyond his years. While he started on a BMX, Matt’s main focus is now Enduro MTB but he was a force to be reckoned with on the road and track through his later school years.

Instagram: @mattsberrys

Lester Perry, 39

Much like Matt, Lester has been riding and racing bikes of all sorts since his early years. Kicking off the two-wheeled experience on a BMX, then moving on to Mountain Biking (back when one bike did it all). Lester dabbled in Road, and Track racing along the journey. His main focus has been on racing Enduro since 2013, but all the different types of bike in the shed still get used from time to time. Lester is part of the Marketing team at EVO and has been in the bike industry most of his life.

Instagram: @lesterperrynz

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