Dan reviews the 2024 Trek Slash

The Trek Slash has undoubtedly been one of the most popular enduro bikes on the market since it was first introduced back in 2011. It was late 2020 when we tested the last version, which impressed us with its buttery-smooth suspension performance and surprising agility for what was a big and burly brawler.

For 2024 however, the Slash has been completely redesigned from the ground-up. Featuring a high pivot suspension design, additional pulley wheels and a mullet setup, it is quite clearly a very different bike to its predecessor.

So how do all the changes play out on the trail? And what about those online reports of chain-dropping issues? We’ll be discussing all of that, and more, in our in-depth review of the new 2024 Trek Slash.

Watch our video review of the 2024 Trek Slash:

It eats up square edge hits for breakfast, while the neutral anti-squat and ABP platform means the back end is unencumbered by drivetrain and braking forces.

An overview of the 2024 Trek Slash

Built for enduro racing and bikepark thrashing, the Trek Slash is designed to compete with the likes of the Merida One-Sixty, Giant Reign and Canyon Strive.

Featuring an all-new frame for 2024, the Slash is now equipped with 170mm of travel front and rear. It comes set up from the factory as a mullet, though by fitting a different shock mount it’s possible to run a 29in rear wheel. The exception is the Small frame size that is purpose-built around 27.5in wheels front and rear.

You’ll still find a four-bar ABP platform, with the most rearward pivot located around the rear axle to help isolate brake forces from the suspension. Trek’s engineers have moved the main pivot almost halfway up the seat tube, which creates a more pronounced rearward axle path. To mitigate chain growth, a large 19T idler wheel routes the chain close to the main pivot. Trek claims this produces around 100% anti-squat all the way through the travel, with the goal being to reduce pedal-bob.

There’s a gazillion other features incorporated into the new Slash, including downtube storage with a second generation hatch design, bolt-on mudguards and frame armour, as well as a flip chip in the lower shock mount that offers linear or progressive suspension settings. While almost every Slash comes equipped with the new RockShox Vivid air shock, the frame is also compatible with coil shocks.

Trek Slash geometry & sizing

Just like the latest Fuel EX, the new Trek Slash incorporates modular headset cups. Complete bikes come from the factory set up in the neutral position with a 63.5° head angle, though by removing the upper headset cup and installing an asymmetric cup you can slacken that out to 62.5° or steepen it to 64.5°. You will have to purchase the asymmetric cup separately for $64 AUD however.

There are some further changes in geometry over the old bike. The seat angle is considerably steeper at around 77-78°, and Trek has also updated the Slash with size-specific rear centre lengths. This is achieved by modifying the location of the BB on the main frame, which varies the rear centre from 429mm on the Small, to 445mm on the XL.

Listed below is the geometry chart below for all five frame sizes. This shows the geometry when matching wheels are fitted (27.5in wheels on the Small, 29in wheels on the M-XL sizes). In the mullet configuration, the angles slacken by 0.2°, the BB drops by 2mm and the rear centre length shortens by nearly 6mm.

Trek Slash price & specs

There are six models in the Trek Slash lineup for 2024. Prices start at $6,999 AUD for the Slash 8, which is the only alloy model in the range. At the other end of the spectrum is the Slash 9.9 XX AXS that sells for a staggering $19,999 AUD. That’s a truly insane amount of money for a bike that doesn’t come with a mid-drive motor.

Thankfully the bike that we’ve been testing is quite a bit more reasonable. It’s the Trek Slash 9.8 GX AXS, which sells for $10,499 AUD. Despite being the second cheapest model it still features a full carbon frame, high performance RockShox suspension and a wireless SRAM GX AXS Transmission, making it an appealing package.

2024 Trek Slash 9.8 GX AXS

• Frame | OCLV Mountain Carbon, ABP Suspension Design, 170mm Travel
• Fork | RockShox Zeb Select+, Charger 3 RC2 Damper, 44mm Offset, 170mm Travel
• Shock | RockShox Vivid Select+, 230x65mm
• Wheels | Bontrager Line Elite 30, OCLV Carbon Rims, 29mm Inner Width
• Tyres | Bontrager SE6 Team Issue 2.5in Front & SE5 Team Issue 2.5in Rear
• Drivetrain | SRAM GX Eagle AXS Transmission 1×12 w/34T Alloy Crankset & 10-52T Cassette
• Brakes | SRAM Code Bronze w/200mm Centerline Rotors
• Bar | Bontrager Line Pro, OCLV Carbon, 27.5mm Rise, 820mm Width
• Stem | Bontrager Line Pro, 35mm Length
• Grips | Bontrager XR Trail Lock-On
• Seatpost | Bontrager Line Elite, 34.9mm Diameter
• Saddle | Bontrager Arvada, Austentite Rails
• RRP | $10,499 AUD

With the Slash however, the smaller rear wheel seems to help counter some that ground-hugging sensation.

Trek Slash weight

Confirmed weight for our Trek Slash test bike is 16kg, without pedals and with the tyres set up tubeless. That’s notably higher than the claimed weight of 15.65kg, and it’s also quite a bit heavier than the previous Slash we tested, which came in at 14.56kg.

Still, it’s in the ballpark for a 170mm travel enduro bike these days, especially one that’s built around a high pivot design.

It’s all pretty burly too, including the Bontrager Line Elite carbon wheelset that weighs a bit over 2kg. These wheels are a great match for the Slash, being quite stiff and also hella durable.

We can’t say the same for the Bontrager tyres however, which at around a kilo each are too lightweight for a proper enduro bike. Unless you want to swap the tyres straight away, we’d recommend at least fitting an insert into the rear wheel to lessen the chance of puncture pain.

Testing the 2024 Trek Slash

We put the Trek Slash into the hands of our enduro tester Dan, who’s aggressive riding styles regularly leaves corners and berms shaking in their boots. Having spent a load of time on the previous version, Dan was perfectly placed to see how this new Slash would compare.

Before putting tyres to dirt however, we had some concerns around the chain-dropping issue that had been reported by reviewers and users online. We spoke with our local Trek dealer, which informed us about a service bulletin that had been issued to address this problem. It turns out that bikes from earlier production runs were being assembled with incorrect spacing for the chainguide, as well as too big of a gap between the chainstay and the lower pulley wheel.

Although our test bike had previously been ridden by another media publication, upon closer inspection we discovered that neither the chainguide spacing or lower pulley wheel were set up correctly. After sourcing the right spacers, a few adjustments with a hex key was all that was required to get everything lined up to spec.

Since making those adjustments we have not once dropped the chain during six weeks of abusive testing. Even still, Trek has informed us that it has developed a replacement upper idler that features taller teeth for more positive engagement with the chain. The replacement idler should be available in early 2024 and will be sent out to Trek dealers to be installed on existing bikes, free of charge.

As such, most customers shouldn’t encounter any chain dropping problems if the bike has been set up properly from the shop. If you are having troubles with your Slash, be sure to check out the service bulletin.

How have you found the fit of the bike Dan?

I’m 183cm tall and the size Large feels spot on. The 488mm reach is almost identical to the previous Slash, but you’re not nearly as stretched out since the seat tube is quite a bit steeper. I still needed to slide the saddle forwards a bit to get a comfortable seated climbing position, but not nearly as much as the old bike.

With that saddle adjustment the Slash fits perfectly. The climbing position is very comfortable, and on the descents you’re nicely centred, giving you a feeling of being ‘in the bike’.

What about the contact points?

The Trek Slash comes standard with 820mm wide bars, which I chopped down to a more sensible 780mm. The Bontrager carbon bars have always looked a bit funny to me, but once I rolled them so that the grips were flat they were fine. They are quite stiff, so you’re likely to notice some feedback at cruising speeds. That said, we’re glad to see a conventional two-piece setup rather than the one-piece carbon cockpit that comes on the higher-end Slash models. Adjustments are easier and it’s obviously a lot cheaper if you want to change out either the stem or bars to suit your preference.

I also swapped the grips straight away, as I can’t get on with the flared alloy lock-rings on the outboard side of the Bontrager grips. I feel like they really dig into the outside of my palms, since I ride with my hands on the very edge of the bars.

Talk us through your suspension setup

Setting up the suspension on the Slash is made relatively easy thanks to Trek’s online calculator. This gives you a great starting point for pressures and rebound settings, all of which are based off your weight. Furthermore, the RockShox Vivid shock has gradients anodised onto its stanchion to help you eyeball sag.

For my 83kg riding weight I needed 209psi to hit the recommended 30% sag for the rear shock. I found Trek’s suggested rebound setting (12/20 clicks) to be too fast for my preference and ended up slowing it down to just five clicks out. I backed the compression adjuster off to its most open position (-2) and ran the Hydraulic Bottom Out dial in the middle of its range.

I set up the Zeb fork as recommended by both Trek and RockShox with 63psi in the DebonAir+ spring. Again I ran a slower rebound setting than suggested, ending up on a 7/18 clicks. I backed off the high-speed compression dial all the way (-2) and added a few clicks from neutral for the low-speed adjuster (+4).

What do you dig about the Trek Slash?

The Trek Slash is an insanely good descending bike. It’s got a great stance on the trail, as you’d expect given the geometry is so close to a full-blown DH bike. However, it’s the top-notch suspension performance that makes it such a beast when gravity takes over.

The RockShox Vivid is very impressive, offering a level of sensitivity that isn’t that far off a coil shock. It’s supple over smaller bumps and chatter, and rear wheel traction is excellent as a result. There’s also great support, and the HBO adjuster allows you to dial in more end-stroke damping if you’re a particularly hard lander.

Trek’s high pivot suspension design has to be commended too. It eats up square edge hits for breakfast, while the neutral anti-squat and ABP platform means the back end is unencumbered by drivetrain and braking forces. This helps the Slash to flow smoothly through chunky rock gardens and high-speed braking bumps, isolating you from the chop while keeping the tyres driving into the ground.

What’s particularly impressive is how the Slash manages to be so plush while maintaining control at higher speeds. It thrives on bombing down steep and technical terrain and it only gets better the harder and faster you push it. With that in mind, I suspect few riders will be likely to find its limits.

Still, I was surprised at how rideable it was outside of full-gas descending. While the suspension is supple, it rides high in its travel and there’s plenty of support for handling bigger hits. This makes the Slash stable and predictable to jump with, and providing you’ve got the inclination, it can be quite playful too.

What does the mullet setup bring to the party?

I think this is a big reason why the Slash doesn’t feel like a total anchor on flowier trails.

In general I like the mullet setup, as it makes the bike more manageable for steep descending. It’s also great through tighter corners, as you’re able to flop the bike over and change direction a bit easier. In these situations a full 29er can stand you up a bit sometimes, especially if you’re on the brakes. Add a high pivot suspension design into the equation and the bike gets harder to manoeuvre due to the way the rear end gets longer as the shock goes into its travel. With the Slash however, the smaller rear wheel seems to help counter some that ground-hugging sensation.

Another factor is the rear centre length, which comes in at just 434mm on the Large frame size. Of course the high pivot design means it does get longer as the suspension goes through its travel. According to Trek, the rear centre grows to 446mm at sag, and ends up at 451mm at full bottom-out.

However, the rear centre length isn’t as dramatic as some other high pivot bikes out there like the Norco Range, and it really helps with agility when slinging through twisty trails. Combined with the smaller rear wheel and supportive suspension, the Slash offers a surprisingly interactive ride quality that encourages you to work the terrain rather than just hang on like a passenger.

We still find it interesting that Trek decided to go for a mullet build out of the box, given this is pitched as an enduro specialist. Of course if you’re serious about racing then you’ll likely want to try the full 29er setup to enhance overall grip and momentum. But we expect there’ll be far more Slash owners that just ride for fun, and for those riders the mullet configuration is the ticket.

What didn’t you like?

No points for guessing that the Trek Slash isn’t the most enthusiastic performer on flatter terrain or at slower speeds.

That’s kind of a given for a 16kg bike with a 63.3° head angle and chunky tyres, and the situation isn’t helped by audible drag from the chain and the two additional pulleys it has to contort around. It’s not as noticeable as other high pivot bikes we’ve tested, which is perhaps due to the 55mm chainline that the SRAM Transmission is optimised around. Keeping the chain clean and well-lubricated is still crucial to minimising noise and banishing the nagging voice in your head when you’re heading up the mountain.

To be fair, I’ve not found the Slash to be a pig on the climbs. The steeper seat tube angle helps a lot, and the rear suspension is for sure more stable under pedalling compared to the old bike. It’s a relatively calm and comfortable affair when you’re winching your way up a steady fireroad climb.

There’s loads of grip for scaling more challenging singletrack ascents, though if the gradient gets especially steep it can be hard to stop the front wheel from wandering around. You’re also more likely to catch rocks and roots with the 27.5in rear wheel, and I found the lengthening rear centre would occasionally disrupt my momentum when getting over bigger ledges. It can still be muscled about, but if you’re looking for all-round performance, setting up the Slash as a full 29er will be worth considering.

Any issues with the chain or the frame?

Thankfully there have been no chain-dropping issues since we got everything set up correctly. It’s also good to know there’s a new upper idler coming that should eliminate the chance of any further problems. The whole saga must have been pretty embarrassing for Trek, but we’re glad to see proactive solutions.

While the chain is managed well, it does end up making contact with the chainstay guard, especially in the higher gears. The rubber protection is more than adequate, though the hard rubber compound results in quite a bit of noise when you’re coasting through bumpy terrain. It’s a fairly dead sound, but I’d still like to see a softer rubber guard to better dampen chain slap.

I also had some popping noises from the headset after a seriously wet and muddy ride, though a quick clean and re-grease was all that was required to silence it. On that note, thank god Trek resisted the trend to route the cables through the headset. The conventional headset and frame-routed cables are so much easier to work on.

The downtube storage is a great concept, and I like the new latch design and the fact that all the plastic components are made from recycled materials. Trek has also updated the hatch with improved sealing, and it all goes together neatly with an almost-flush profile.

However, the opening in the downtube is still a bit small, and that issue is exacerbated by cable guides that sit on either side. It creates an additional snag point that meant I couldn’t actually fit a standard inner tube with the provided storage sleeve. A lightweight inner tube and careful packing will do the trick, but I wouldn’t put any tools inside the sleeve as it makes installation and removal harder.

We also had the same problem with the removable rear axle lever as we did on our Fuel EXe test bike. The lever has never popped out on its own, but the sloppy tolerance means there’s a fair bit of play while riding, leading to an annoying rattle.

These issues of refinement were more noticeable given the finish on the Slash frame is otherwise really good. The included bolt-on mudguards and downtube protection are nice touches, and the fact that Trek gives you a lifetime warranty on the frame provides great peace of mind.

Component highs & lows

As far as the 2024 Trek Slash lineup goes, we reckon the 9.8 GX AXS model tested here is the pick of the bunch. It costs quite a bit less than the higher-end models, but loses out very little in terms of performance.

The suspension is excellent, with the new Vivid being a particular highlight. I had no issues with the Code Bronze brakes, which offer great power, consistency and a nice lever feel.

SRAM’s GX Transmission has worked flawlessly throughout testing, though in typical fashion I discovered a problem right at the end of the review period. For some reason the clutch isn’t returning cleanly anymore, resulting in a lack of tension on the chain in the higher gears. We’re unsure if there’s any damage that might have been caused by an impact, though the derailleur isn’t wearing any scars to suggest this is the case. Either way, SRAM will be replacing the derailleur under warranty and we’ll send this one back to be assessed. It’s the first issue we’ve had of any sort with the latest SRAM Transmissions, and given how hard we’ve flogged the XX and X0 groupsets in our long-term review, it feels like an anomaly.

There were zero doubts about the puncture-prone Bontrager tyres. The rear ended up with a total of seven Dynaplugs scattered across the tread and bead before it finally gave up the ghost after a hefty blowout on the trails of Mt Buller. Unusually for me, I also punctured the front tyre close to the bead. I’ve not had problems in the past with the Bontrager SE6/SE5 tyres on the Rail or old Slash, so who knows, maybe it’s just the new Slash encouraging me to take uglier line choices?

Traction is otherwise dependable in dry and rocky conditions. Bontrager’s rubber compound isn’t the softest going, so grip does suffer on wet roots and rock slabs, and that’s exacerbated by the higher pressures you need to run to avoid punctures. As I mentioned earlier, consider fitting a CushCore insert in the rear wheel at the very least, or swap out the tyres for something with a tougher casing and softer rubber.

Given all the pinch-flats, I’m happy to report that the carbon wheels have been absolutely rock-solid. The rear took a particularly gnarly hit coming off the top of Mt Stirling, but neither wheel is yet to require so much as a spoke key. Even if you do manage to damage one of the carbon rims, it’s good to know that Bontrager offers a 2-year crash replacement scheme.

Flow’s Verdict

We’ll admit that we were somewhat skeptical when we first got wind of the 2024 Trek Slash. We genuinely loved the old version, and there was concern that some of its magic would be lost in Trek’s pursuit of the high pivot trend. Thankfully that hasn’t been the case, with the new Slash being one of the most impressive enduro bikes we’ve ever tested.

Unfortunately for Trek, the Slash ended up having a rough start due to those early reports of chain-dropping. However, we’re glad to report that with the correct setup our test bike has been flawless in this regard. It also turns out that the combination of a high pivot suspension design, Trek’s ABP platform and RockShox’ superb Vivid shock delivers outstanding rock-devouring performance. Along with the sturdy chassis and raked-out geometry, the Slash offers a floaty ride quality that allows you to charge with confidence.

It ain’t a complete freight train though. Yes it needs an aggressive rider who likes to push hard, but for a 170mm travel enduro bike it’s surprisingly well-rounded and has been a great partner on longer days out. We have to give kudos to Trek for committing to the mullet setup, which injects a good deal of pep given this bike’s outrageous grip and stability. Add in all the clever in-built wheelsize, geometry and suspension adjustability, and there’s loads of scope for tweaking the geometry and ride quality to your preference and terrain.