Review: Trek Slash – More ‘dynamic edge’ than ever before

The Slash is now a highly-refined speedster that broadens pace and possibilities on the trail

| WORDS: Myles Kelsey | IMAGES & VIDEO: Gary Perkin & Retroyspective | LOCATION: Tokai, Cape Town |

First released as a 26″ wheel size bike in 2012, the Slash moved to a 27.5″ platform a few years later before settling into the 29″ wheel size around 2017. Through those years and in pursuit of all-out race pace, Trek tweaked the travel, geometry, kinematics and suspension technology too. Correction: ‘tweaked’ is an understatement – let’s rather say the technology has been dramatically improved. It’s not that the early models were clunkers. Not at all. It’s just that having ridden most of those early bikes then fast-forwarding to this latest iteration (which I bought by the way) the difference is day and night; chalk and cheese; burgers and salad. Anyway, you get the picture. On the trail, the sheer pace and possibilities of the new Slash are ludicrous. It has me thinking: it’s astounding what the bike industry – and in this example Trek – can achieve in a decade of development. Without venturing off-topic, I’d easily say the pace of development in the bike industry dwarfs that of the car and motorcycle industry but that’s an opinion I’ll dig into another day. Here’s my long-term review of the Slash.

Review Trek Slash mountain bike as written by Myles Kelsey of Bike Network in South Africa
Trek Slash 9.8 model currently retails for R110k.

FEATURES & DETAILS

Review Trek Slash mountain bike as written by Myles Kelsey of Bike Network in South Africa
The Slash is now a 160mm rear travel bike with a 170mm (stock) or 180mm (allowed) fork.

Trek hasn’t deviated from the ABP split pivot layout and there is no need to as it’s one of the best systems on the market that’s race-proven, well-refined and especially good when braking over rough surfaces. The kinematic changes on the new Slash include a higher anti-squat number to improve efficiency when pedaling.

Review Trek Slash mountain bike as written by Myles Kelsey of Bike Network in South Africa
The ABP (aka split pivot) sees the chainstay and seatstay pivot on the rear axle. It’s a layout that is not particularly easy – on a manufacturing level – but the performance benefits, especially when under braking are of the very best available.

The crew at Trek worked with suspension maker RockShox to develop a shock that does some pretty simple things, really well. The ThruShaft is a solid damper shaft that extends outside the body of the shock when it compresses. It uses a solid column of oil with a single damper piston – as opposed to a chamber, floating piston and compressed air system. The net effect is ThruShaft switches from compressing to extending very quickly and in doing so responds faster to changes in the terrain. The idea, says Trek, is to give the rider more grip, control and a smoother ride.

Review Trek Slash mountain bike as written by Myles Kelsey of Bike Network in South Africa
The proprietary Super Deluxe shock from RockShox has a numbered rebound dial, lockout lever and three compression settings to play with on the trail. Internally, volume spacers can be fitted to make your ride feel more linear or more progressive.

The shock also has a lockout lever for shuttle road climbs and a numbered rebound dial so it’s a little easier to check your settings. And 3 low-speed compression settings. Zero is a neutral setting which is your fit-and-forget option for most trails. The minus setting reduces compression which improves control on steep terrain and rollover on very rough terrain. The plus setting adds compression which improves control on flow lines with berms and jumps.

Review Trek Slash mountain bike as written by Myles Kelsey of Bike Network in South Africa
All models of the Slash now feature this neat internal storage compartment on the downtube of the frame for storing tools, snacks, tubes, wind jackets and so on.
Review Trek Slash mountain bike as written by Myles Kelsey of Bike Network in South Africa
The range of the Knock Block steering lock system has been increased to around 77°. For riders who don’t like the system, it is also completely removable.
Review Trek Slash mountain bike as written by Myles Kelsey of Bike Network in South Africa
The frame protector now covers the full length of the downtube – which is great for shuttling too.
Review Trek Slash mountain bike as written by Myles Kelsey of Bike Network in South Africa
This 9.8 model is decked with carbon Bontrager Line Elite 30 wheels and the brands SE5 and SE6 tyre combination.

The SE6 uses a two, two, three center knob pattern with multi-directional sipes and staggered shoulder knobs for corner grip. The SE5 is focused a little more on rolling speed, with braking edges and corner grip.

Review Trek Slash mountain bike as written by Myles Kelsey of Bike Network in South Africa
My SRAM build, on a size large, weighs in at 14.7kg which is very similar to the XT build. Interestingly the alloy frame Slash is only 300grams beefier than the carbon one and it runs on the same kinematic, geometry and travel.
Review Trek Slash mountain bike as written by Myles Kelsey of Bike Network in South Africa
The new frame has lower standover numbers and shorter seat tubes to meet rider demands on steep, gnarly lines.

GEOMETRY & SIZING

The geometry changes are pretty significant. The head angle is now at a slack 64.1° and the seat tube angle is around 2° steeper at 75.6°. Through the size curves, there’s extra rider clearance courtesy of shorter seat tubes, the reach is 15 to 40mm longer and the stems are now all 15mm shorter at 35mm.

Review Trek Slash mountain bike as written by Myles Kelsey of Bike Network in South Africa

For geometry adjust fans, the Mino Link flip-chip switches up the head angle by 0.5° and the BB by 7mm. Of course, with all these changes the wheelbase grows a touch too and that contributes to greater stability at speed.

Review Trek Slash mountain bike as written by Myles Kelsey of Bike Network in South Africa
The flip-chip sits on the top of the seat stays and you can swap the setting in less than 5 minutes.

If you are getting ready to pull the trigger on a new Slash then remember to factor in the short stem when selecting frame size. All the frame sizes are stocked with a 35mm stem now which means although the reach numbers are big on the geo charts, the bikes are not massively bigger. In my case, I’m 1.76m tall and I rode a size Large on the previous iteration and ride a size Large on this new model.


RIDE IMPRESSIONS

Review Trek Slash mountain bike as written by Myles Kelsey of Bike Network in South Africa
I’m 1.76m tall and ride a size large frame.

So there are a lot of little things on this Slash that combine really well to produce extra sparkle on the trail. First off, let me just say the suspension performance is simply sensational. The shock requires very little force to move and it changes direction quickly – it feels as buttery as a coil shock. I’d even say the small bump performance is better than any air shock I’ve ridden. Diving into the deeper end of the travel it feels like there is more than 160mm available, and I have yet to feel any harsh bottoming.

Review Trek Slash mountain bike as written by Myles Kelsey of Bike Network in South Africa
The small bump performance and mid-stroke support are sensational. Steep, janky lines are pacey and composed and this is really where the bike shines.

SUSPENSION SETUP | I’d recommend running the compression in the zero setting then you have the ability to switch it either way to suit different lines. You also have the ability to adjust the air chamber with volume spacers to further dial in the progressivity – but I haven’t dived into that territory yet. Upfront the Zeb is pretty easy to set up – and those big stanchions help the bike track true on any terrain. For my weight (71kgs) and riding style, I run 2 tokens and 60 psi in the Zeb. I tried the fork on 170mm for the first month or so before bumping it up to 180mm (all you need is a new air spring from RockShox) and I’m really liking the feel of it at 180mm.

Review Trek Slash mountain bike as written by Myles Kelsey of Bike Network in South Africa
It pops!

Being a gravity-focused bike, I never expected it to be quite as poppy and agile as it is. I think the low rotational mass of the Bontrager wheels and tyres contribute to this playful fun nature of the new Slash. On jump lines and flow trails it’s easy to boost and hit the sweet spot of the landing with complete accuracy – and when you do – the acceleration is simply crazy.

On a flow line at a local bike park in Cape Town, it’s hands down the fastest bike I’ve ridden and GPS data confirmed that. The acceleration is ludicrous and what’s blatantly obvious is that ‘holding the speed’ is easier than on the previous model. This is definitely a good bike for racing – DH or Enduro. The single gripe I have is with the MRP chain device that is standard on the bike – it’s rather loud. So it’s effective in that I didn’t drop the chain but I couldn’t quite get it set to reduce the chain clanging about on the lower piece of it. To be fair, hauling the mail on any trail bike does result in a fair bit of chain slap noise but I feel the guys at MRP need to develop their product a little. Swapping to another brand chain device solved most of the issue – and I’d recommend that. What I really like about this bike is the feel of the short 35mm Bontrager stem. At first, I was concerned about not being able to weight the front end in the turns but on the trail that wasn’t an issue at all. In fact, the short stem sharpens up the steering a little and I think it combines exceptionally well with the shorter offset forks we are all using now. It just feels right.

Review Trek Slash mountain bike as written by Myles Kelsey of Bike Network in South Africa
Cornering pace and line accuracy are impressive and I think a lot of that is down to the new geometry and particularly the short stem that combines well with the short offset fork.

HOW VERSATILE IS IT? | Bontrager are making moves with their tyres and the SE6 / SE5 combination on the Slash are the fastest rolling Enduro rollers I’ve ridden. Now coupled with the lockout lever and light rotational mass, the bike climbs better than you think a 160mm bike should. Fact. You’ll like that because it means you can do another lap at your local bike park. Let’s be fair here, on the Slash you are not gliding up the climbs like Jolanda on her Supercaliber but you are getting up for another run and those descents are really where the Slash parties.

Review Trek Slash mountain bike as written by Myles Kelsey of Bike Network in South Africa
I think the best way to describe the ride of the new Slash is that the “edge” of what was previously possible on a trail is now broader and easier to find. Consequently, it is a lot safer at speed than the previous iteration.

CAN YOU MULLET IT? | Short answer is you can but I wouldn’t. I did about 10 hours of riding with a 27.5″ wheel (on the back which with a 29″ wheel on the front makes the bike a “Mullet”) and the bike definitely rides better as an all 29″ platform. The main reason is the risk of pedal strikes when running it as a mullet is just too high – so I wouldn’t recommend it – especially if you ride rocky trails.

FINAL IMPRESSION | Everything knits together really well on this new Slash. It’s a fun, composed and very quick ride. I can see why it’s already won so many “Bike of the Year” awards.


TAKEOUT & WHO IT IS SUITED TO

It’s obviously built for big mountain riding but that doesn’t mean it’s not a fun bike on tamer gradients. Having a lot of travel and bigger rubber means your climbing speed is lower but it also means you can slay any corner, jump or rock line in town – and that’s where the jol factor comes in.

Review Trek Slash mountain bike as written by Myles Kelsey of Bike Network in South Africa
It’s more than just an Enduro bike. It’ll ride big trails, big gradients, long days and downhill too.

Although the Slash is an Enduro race bike built for gnarly lines it is actually a lot more versatile than that. I found it performs very well on most DHy lines – especially with gravity casing tyres. The standard Bontrager tyres are no slouch on backcountry rides through rolling terrain and help get the distance in. Think of it as a big travel trail bike that can be dressed up for DH racing or dressed light for a big workout on a 50km / 1500m type day on rolling terrain. It’s suited to riders who are into big trail rides, Enduro racing, Downhill and bike park shuttle outings.


VIDEO SUMMARY


RELATED: How to eMTB | Start HERE


ABOUT THE TESTER

Myles Kelsey // 43 years of bike racing experience from BMX, to Track, Road, XC, Enduro and Downhill // Former Masters Mountain Bike World Champion // MTB Skills Coach // No industry affiliations or sponsorships // Searching good times on two wheels