Trail and Enduro Bikes


Our former benchmark 29er under scrutiny

Words and Images: Ieuan Williams

The Slash 29 is a bike that hit the mountain bike community by storm. With Session styling in its DNA and two first place spots in the Scottish Downhill series at the start of the year, the Trek Slash seemed to be fast enough when the going got tough. Having previously ridden the 2017 Slash in the 9.9 build configuration it was an obvious choice for a benchmark bike for the Dirty Dozen and one other bikes would have to do well to beat. However, with Trek now removing this specification and going with the 9.8 as the flagship build, it faced its own challenge of living up to the memory of the beast we rode previously.

If looks are anything to go by then it’s still got it. Trek have always been known for their attention to detail. The Slash is no exception, with the in-house carbon production allowing for standards to be kept high. The main difference for the 2018 bike is the new Through Shaft damper from RockShox. This metric shock changes out the old Fox Float X2 damper from the 9.9.

Trek have also changed out the full carbon frame for the 9.8 build. An aluminium chainstay has been introduced. We were intrigued to see how this affected the ride dynamic.

Frame: OCLV Mountain Carbon main frame, alloy 1x-specific stays, ABP, Boost148, Knock Block, EVO link, E2 tapered head tube, Mino Link, Control Freak internal routing, Carbon Armor, ISCG 05, G2 Geometry, 150 mm travel

Rear Shock: RockShox Deluxe RT3, RE:aktiv with Thru Shaft 3-position damper, tuned by Trek Suspension Lab, 230×57.5mm

Fork: Fox Performance 36 Float, GRIP 3-position damper, E2 tapered steerer, Boost110, G2 Geometry w/51mm offset, 160mm travel

Rear Derailleur: SRAM GX Eagle, Roller Bearing Clutch

Shifters: SRAM GX Eagle, 12 speed

Chain set: SRAM Descendant 7k Eagle, 32T Direct Mount X-Sync

Bottom Bracket: PF92

Cassette: SRAM GX Eagle, 10-50, 12 speed

Chain: SRAM GX Eagle

Brakeset: SRAM Guide RS hydraulic disc

Handlebars: Bontrager Line Pro, OCLV Carbon, 35mm, 27.5mm rise, 780mm width

Stem: Bontrager Line Pro, Knock Block, 35mm, 0 degree, 50mm length

Headset: Knock Block Integrated, sealed cartridge bearing, 1-1/8˝ top, 1.5˝ bottom

Grips: Bontrager Rhythm, dual lock-on

Wheelset: Bontrager Line Elite 30, Tubeless Ready aluminium rims, 108T Rapid Drive, Boost front and rear.

Tyres: Bontrager SE4 Team Issue, Tubeless Ready, Core Strength side walls, aramid bead, 29×2.40˝

Saddle: Bontrager Evoke 2, chromoly rails

Seatpost: Bontrager Drop Line, internal routing, 31.6 mm (15.5: 100 mm/17.5 & 18.5: 125 mm/19.5 & 21.5: 150 mm)

Weight: 17.5″ – 14.06 kg


With slick and smooth lines and a carbon finish to die for, the 9.9 version bike always made you feel that you were on something special no matter how quick it was. This 2018 9.8 Slash 29 holds many of the previous bike’s traits just for a smaller price package so it should be ace. Right?

With the size XL test bike built and ready for action it is noticeable that the specification is not representative of a flagship bike in the same way that the 2017 Slash 9.9 was. The mid range SRAM Guide R brakes and GX Eagle 1×12 transmission are solid performers but just something we might also expect to see on a base model.

Wheel wise, it’s a welcome sight in the way of some Bontrager Line 30 wheelset and SE4/SE5 rubber, the same as the 9.9. This aluminium wheelset worked well on the 2017 bike and once again it is a hit on the new build.

There are a few major changes from the older and higher spec bike though, mainly the rear Through Shaft RockShox damper, which is new and unique to Trek for 2018. The previous bike came with a Fox Float X2 unit – never my favourite of shocks but after some set up it held up to the abuse and felt great. This new damper from RockShox on the other hand it felt great for the first hour then developed a serious knock and totally packed in. We were told this was due to a fault in the seal but, even with this in mind, it is not a great start on what was one of my favourite bikes.

Ride wise, forgetting about the damper for a moment, this bike is still fast! There is no taking away from the ability of the shape and purpose here. The 65.6° head angle is bang on and promotes confidence and stability when descending. The bottom bracket is a little high, measuring in at 351mm – it would be interesting to see this around the 340mm mark. This is a similar to the issue we had with the Trek Session.

The sizing on the XL bike was bang on for me other than the seat tower height. With the availability of 170mm dropper seatposts now I really do not see the need for these high towers anymore. It is not a major point but just one that would make this bike more poised in the air when that seats well out of the way. One thing that the Intense Carbine had spot on.

The Slash now has an aluminium rear chainstay to replace the carbon one on the 9.9 model. This really does not affect the ride in a bad way. It actually helped to give a little extra wag in the tail for a less stiff feel.

This mentioned, it leads nicely onto the fatigue. We changed the cockpit to a wider bar with a more regular shape (as we’re not keen on the stock Bontrager bar) along with a shorter Easton stem – a set up we used on the 2017 Slash 9.9 test bike. It is now very easy to get lost in a day dream climbing up a technical ascent. The super light feel to the ride and light, compliant aluminium wheelset means the rider’s body does not get beaten about. This said, the Slash hunkers down and compliments being ridden hard but now allows a certain amount of give before it stiffens back up and sends you on the way.

Even without upgraded stoppers, bar and stem and some suspension setup (or repair) this Slash is still a fantastic bike. Not as good as the previous model though and I would still buy the 9.9 if it was available. With the likes of Whyte pushing out a great carbon chassis bike in the S-150 for similar money with better components, the Trek Slash 9.8 now has some serious competition.

PRICE: £4800

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