If you were looking for a purebred enduro e-mountain bike, you probably avoided Trek in the past. With the Rail, the company has always stopped at 160 millimetres for the suspension fork and 150 millimetres for the shock. For the 2025 season, the manufacturer is closing this gap in its range. The blueprint for the newcomer is a model without a motor, with which Trek has already won a number of awards.
Name, geometry, technology – the Trek Slash+ borrows everything from the renowned Trek Slash. Most importantly, however, the additional ground clearance compared to the Rail. Thanks to 170 millimetres of suspension travel both front and rear, you can now also have a blast on really rough trails with an ebike from the US-American industry giant. Find out what makes this bike so special here in detail.
1. Trek Slash+: the frame
2. Trek Slash+: the ebike system
3. Trek Slash+: fork and shock
4. Trek Slash+: the bike suspension
5. Trek Slash+: the model range
1. Trek Slash+: the frame
Even with the Rail, Trek repeatedly took its cue from the Slash and tried to transfer key characteristics to its eMTBs with a longer suspension travel. In the case of the Slash+, this can now be communicated very transparently. It starts with the frame material. The same OCLV carbon fibres are used as for the Slash frame. The manufacturer applies an additional laminate under the paint. This is intended to protect the carbon even better from damage caused by impacts.
Accessories for more flexibility
The shape and geometry are very similar to the sister model without an electric drive. The effective seat angle of 77 degrees promotes efficient power transfer when pedalling, so that even on longer, steep climbs, you can still have fun. On the other hand, if you’re going downhill at a steep angle, the flat seat angle makes steep descents seem less intimidating. Trek supplies the bike with a seat angle of 63.5 degrees as standard. You can also purchase special headset cups as an option, which allow you to lower the angle by another degree to 62.5 degrees. Even in this setup, the bottom bracket height remains unchanged at 352 millimetres.
Like the Slash, the Slash+ rolls on wheels of different sizes. To help it tackle obstacles, Trek uses a 29-inch diameter at the front. The smaller 27.5-inch rear wheel helps it handle technical sections with agility.
2. Trek Slash+: the ebike system
Trek was able to gain a lot of experience with the HPR50 from TQ on the Fuel EXe. Overall, this seems to have been extremely positive. After all, the manufacturer rates the system with its torque of only 50 Newton metres as sufficient for an enduro-capable ebike. Some of you would probably have expected a drive that generates more of the usual 85 or 90 Newton metres.
Not more powerful, but more enduring
The new, larger battery could have been the deciding factor in favour of the TQ system. The previous capacity of 360 watt hours has now been increased by a further 220 watt hours. This should significantly increase the range. So you can choose the highest of the three support levels with a clear conscience if the incline requires it. And in the case of a drive whose performance is more on a medium level, this may occur more often.
At the same time, the HPR50’s low system weight ensures that the ebike itself weighs less than expected. The 20.5 kilograms for a size M model are considerable. After all, we are talking about an e-mountain bike with a long suspension travel and not a race-optimised cross-country bike. A comparatively low mass has to be accelerated, which to a certain extent compensates for the performance disadvantages of the motor. A 160 watt-hour range extender can also be used to expand the energy buffer for your tours.
3. Trek Slash+: fork and shock
We’ve already mentioned it a few times: the suspension system is the same size as that of the Trek Slash. For jumps, rocky trails, big drops and everything else that goes with a typical enduro experience, this is a good level of suspension to meet such challenges. Depending on the equipment, Trek uses components from Rockshox and Fox. RockShox ZEB Ultimate and Fox Rhythm 38 Float EVOL as a suspension fork and RockShox Vivid Ultimate as well as Fox Performance Float X as a rear shock will make many a heart beat faster.
Fortunately, the special integration of the shock in the frame has also been adopted from the Slash. There is a flip-chip in the lower shock mount. This allows the shock to be moved into two different positions. The “More” position offers more resistance to impacts. Those who put more of their own body weight on the bike or replace the actual shock with a model with a steel spring should be able to cope better with the trails with this. In the “Less” position, the shock reacts more sensitively, which is better suited to a gentler riding style.
4. Trek Slash+: the bike suspension
Even those who don’t know much about bikes will quickly notice that the chain runs in a rather strange way on the Trek Slash+. From a pulley over the chainring to a second pulley and then to the derailleur – that’s unusual. The reason for this design is the high-pivot suspension of the e-mountain bike, which celebrated its premiere on the Trek Slash. To explain the design, you can’t get around some technical terms. ;-(
On a full-suspension e-mountain bike, the rear triangle rotates around a main pivot. Usually, this main pivot is positioned close to the bottom bracket. If the rear wheel of the bike with such a suspension hits an obstacle, the rear wheel axle moves almost vertically upwards on the axle path. As a result, the shock compresses and absorbs the impact. This approach works, but can lead to the rear wheel getting caught on the obstacle, at least in terms of how it feels, especially in really rough terrain.
The smarter rear wheel swings backwards
On the Trek Slash+, on the other hand, the main pivot is located higher up than the bottom bracket. This design is called a high pivot. With a suspension like this, the movement of the rear wheel is better aligned with what is happening on the bike. An obstacle wants to slow you down. The forces that arise during the impact act in the opposite direction to the direction of travel. If the rear wheel moves a little in exactly the same direction, the impact loses some of its force. You won’t be shaken up as much, you’ll have to compensate for fewer vibrations and you’ll tire much more slowly.
What you can’t see from the saddle while riding is that the rear wheel’s axle moves slightly backwards from the centre of the bike when the rear wheel hits an obstacle. In practice, this feels like your bike can react faster to the obstacle. In addition, the rear wheel has less airtime, so it comes back into contact with the ground faster. This makes the ride feel more controlled because you gain traction. The faster the rear wheel comes back down, the faster it can accelerate again.
This sounds great for downhill riding. Unfortunately, it usually feels less great when pedalling. This is because the backward movement of the rear wheel increases the distance between the cassette and the chainring. As a result, the chain slackens. It’s as if someone were suddenly pulling it backwards, taking the crank with it. This kick is extremely irritating when riding and, understandably, bad for propulsion. Trek has counteracted this phenomenon with the two pulleys, so that it doesn’t even occur. The upper pulley ensures that the shock absorber can operate largely undisturbed. The lower pulley minimises the chain tension below the chainstay, so that the rear derailleur always works perfectly. Incidentally, the rougher the terrain, the more pronounced the differences between a high pivot and a design with a lower pivot point.
5. Trek Slash+: the model range
The model range is laid out clearly for the launch. There are exactly two different configurations. The most luxurious can be found on the Trek Slash+ 9.9 X0 AXS T-Type. It differs mainly in terms of the suspension system, wheels, gearing and brakes from the more affordable Trek Slash+ 9.7 SLX/XT. The suspension fork and rear shock are both from Rockshox, the ZEB Ultimate and Vivid Ultimate. Just like the wheelset, carbon is also used for the handlebars. The electronic derailleur from Sram is a model from the Transmission series that does not require a derailleur hanger. And the Sram Maven Silver with its 200-millimetre brake discs is one of the best braking systems you can currently buy. All in all, this comes to a price of 11,999 euros.
Undoubtedly a considerable sum. The entry-level model costs 4,000 euros less. At least in terms of the suspension system, the Fox Rhythm 38 Float EVOL suspension fork and the Fox Performance Float X damper are on a par with the top model. As expected, the wheelset can no longer be fitted with carbon rims. You’ll have to make do with aluminium here. Perhaps the most disappointing thing is that you don’t get an electronic shifting system for around 8,000 euros. Basically, there’s nothing wrong with the mix of Shimano XT and SLX groupsets that’s been built in. However, at this price level, one or two expectations might be different. The same applies to the brakes.
Trek Slash+ 9.9 X0 AXS T-Type in the colour Pennyflake
Trek Slash+ 9.7 SLX/XT in the colour Olive Drab
Trek Slash+ for the 2025 season at a glance
- Variants: Trek Slash+ 9.9 X0 AXS T-Type, Slash+ 9.7 SLX/XT
- Frame: OCLV Mountain Carbon
- Suspension fork: RockShox ZEB Ultimate, Fox Rhythm 38 Float EVOL
- Battery: TQ 580 Wh
- Drivetrain: Sram X0 Eagle AXS, Shimano XT M8100
- Seatpost: RockShox Reverb AXS
- Brakes: Sram Maven Silver, Shimano M6120
- Weight: from 20.38 kg in frame size M
- Maximum permitted total weight: 136 kg
- Colours: Mercury, Pennyflake, Olive Drab, Red Smoke
- Prices: from 7,999 euros
Pictures: Trek Bicycle Corporation