Trek Rail 2021 Review | A powerful, long travel e-MTB with ALL of the confidence

The not-so-minor details


2021 Trek Rail 9


Trek Bicycles Australia


$10,499 AUD




- Raw speed and 'GET OUT OF MY WAY!' stability
- Buttery smooth suspension performance
- The robust ZEB
- Mega traction
- Powerful and highly responsive motor
- Discreet and well-positioned Kiox display unit


- Motor rattle
- Mode selector is bulky and awkward
- Special key needed to remove the battery

Dan tests the 2021 Trek Rail 9

First introduced to the world for 2020, the Rail is Trek’s premium long travel electric mountain bike. As the natural successor to the Powerfly LT, the Rail offers significantly improved geometry, and it’s built around the latest generation Bosch motor with a 625Wh battery in the downtube. Equipped with 29in wheels, 150mm of rear travel and a 160mm fork, it’s essentially the e-MTB version of the Slash. It’s a similarly capable and planted beast on the descents, though with 85Nm of torque between the crank arms, it can go up some rather extraordinary terrain too.

2021 trek rail 9 emtb bosch
There have been some big updates to Trek’s big-travel Rail for 2021.

What’s changed for 2021?

While the Rail was already a brand new platform for 2020, Trek has implemented some significant updates for the 2021 model. And we’re not just talking Bold New Graphics™ here.

The biggest change – both figuratively and literally – is the new RockShox ZEB fork that now adorns the front of the Rail. At the very least a better visual match for the hulking downtube and buxom head tube, the ZEB also brings welcome assuredness to the front end thanks to its fatter 38mm upper tubes and mahoosif crown.

To match the supple ZEB, Trek has bolted in a custom rear shock. It’s the Super Deluxe Ultimate RT3 – the same shock found in the latest Slash, which has been codeveloped with RockShox and features the IFP-free Thru Shaft damper. It lends a big change to the overall ride quality, which we’ll touch on in more detail in a bit.

A 4th generation Bosch Performance CX motor still powers the Rail, but it has been updated with the latest software that’s unlocked a further 10Nm of torque over last year’s bike. The system also features Trek’s custom ‘eMTB Lite’ mode in place of the usual Tour mode.

The old-school Purion display is gone in favour of the snazzy Kiox head unit, which Trek places on the top tube just behind the Knock Block headset. A separate control unit now sits next to the left-hand grip, giving you fingertip control of the various assist modes.

2021 trek rail 9 emtb bosch
Bosch updated the software in the Performance CX motor last year to give it an extra 10Nm of power.

The Goldilocks model

For the past five months we’ve been testing out the mid-spec Goldilocks model – the Rail 9. This bike is flanked by the cheaper Rail 7 ($8,999 AUD), and a pricier, carbon-framed Rail 9.8 ($11,799 AUD). All Rails are produced in four sizes from Small through to XL, which Trek claims will fit riders from 153cm to 196cm tall.

Selling for $10,499 AUD, the Trek Rail 9 is on the pricey side compared to the latest Merida eOne-Sixty 9000 and the Norco Sight VLT C1 29, both of which feature carbon frames. However, it does offer notably better specs than the similarly-priced Specialized Turbo Levo Comp.

Of course specs and numbers on paper are one thing though – how a bike rides on the trail, how it handles and what it’s like to live with day-to-day is another thing altogether. To see exactly what the new Trek Rail is capable of, we put it into the hands of our tame enduro tester Dan. Read on for a closer look at the package, followed by our review of the Rail.

2021 trek rail 9 bosch emtb electric mountain bike
We’ve had the Trek Rail 9 in for a long-term test, and have gotten to know the Goldilocks e-MTB very well in that time.

2021 Trek Rail 9 Specs

2021 trek rail 9 emtb bosch
Our tester Dan, out in the middle of nowhere with zero mobile phone reception.

Testing the Trek Rail

Having already spent a load of time testing the latest Trek Slash, Dan went straight onto a Large-sized Rail to match his 183cm height. The 465mm reach is about 20mm shorter than the Slash. However, the effective reach is almost identical, as the Rail comes with a slightly longer 50mm stem. The overall riding position is comfortable and relatively upright, complemented by Bontrager’s own 780mm wide riser bars and Arvada saddle.

Setup is otherwise straightforward on the Rail thanks to Trek’s online suspension setup calculator. We followed the recommendations for Dan’s 83kg riding weight, and ran the fork with 20% sag and the rear shock with 30% sag. The big volume tyres were setup tubeless with 24psi in the front and 26psi in the rear.

Confirmed weight for our test bike without pedals is a smidge lighter than claimed at 23.92kg.

2021 trek rail 9 emtb bosch
The RockShox ZEB is such a good performer, and a mighty match for the beastly Rail.

The suspension is insane

For sure one of the biggest standout qualities of the latest Trek Rail is just how bloody good the suspension is. The new Super Deluxe shock already impressed us on the Slash, but it’s even better here thanks to the improved sprung-to-unsprung mass ratio of the stockier Rail.

While it does look like a conventional Super Deluxe shock, the internals are anything but. Compared to the 2020 model, the new shock has ditched the RE:aktiv valve in favour of a standard shim stack. Essentially some of the pedalling support has been traded up for a gooier feel with a greater focus on traction and high-speed reactivity. You can still flip between Open and Firm settings via a two-position lever, and there’s also a separate dial for adjusting the low-speed compression damping in the Open position. We mostly left the low-speed dial in the neutral position, though the firmer option is useful for riding flowier jump trails where you want a little more support to push off of when pumping the bike through rollers and berms. The softer position is ideal for wet days and steep, traction-poor trails.

2021 trek rail 9 emtb bosch
This shock is absolutely unreal. So plush, so reactive, so much control!

The near friction-free feel is amplified by the Thru Shaft damper, which skips the traditional nitrogen-charged IFP. The main damper shaft exits the base of the shock during compression, allowing for a constant column of oil inside the shock. Trek claims the Thru Shaft design reduces the ‘stick-slip’ sensation when the shock changes direction between compression and rebound.

On the trail, we’d have to agree with those claims. The back end of the Rail offers glue-like traction with impeccable small-bump compliance, and the rear wheel gets out of the way with incredible efficacy when it meets something hard and fast. Combined with the ABP platform, which helps to reduce the affect of braking on the suspension, it offers a very active and neutral feel. While Dan didn’t mess around with the compression settings much, he did tweak the rebound dial a click or two depending on the trail, going for a slightly slower setting on bigger jump trails to reduce back-end kick, and a faster setting for speedier recovery on rougher flat-out moto trails.

2021 trek rail 9 emtb bosch
The Rail is built for high-speed ripping, with even more stability than the Slash.

Up front, the ZEB is a fantastic complement to the rear suspension and the Rail’s frame in general. We’ve spent considerable time on the ZEB Ultimate (both separately and on the Trek Slash), and both the chassis and DebonAir spring are identical in this cheaper Select+ model. The difference is in the damper, and while you do get adjustable rebound and low-speed compression damping, you miss out on the high-speed adjuster.

Performance on the trail is very similar between the two though, and we can’t say we missed that extra adjustment. It is possible to increase spring support by adding a Bottomless Token to the air spring, but we never needed to – from the factory the ZEB is plush, well controlled and it looks proper alongside the Rail’s vast front end.

2021 trek rail 9 emtb bosch
You only get low-speed compression adjustment on the ZEB Select+ fork.

Two-wheeled monster truckin’

With the stout ZEB and oozy suspension, the Rail absolutely loves going full-gas on steep terrain. In fact, we struggled to find any limit to its high-speed capabilities, which really aren’t that far off from a dedicated dual-crown downhill bike.

There is so much stability on offer – of course the generous mass helps, though the front wheel also tracks a predictable path thanks to the 44mm fork offset and slack head angle. On that note, the head angle is actually a bit slacker than claimed – we measured it at just under 64°, likely because the ZEB is slightly taller than an equivalent Lyrik. The Rail’s front end has a similar vibe to the raked-out Sight VLT, though it delivers noticeably less wiggle compared to the steeper head angles and 51mm fork offsets used on the Levo and eOne-Sixty. The Rail trumps all of them though with its effortlessly smooth suspension performance, which enhances high-speed control and generates traction on rough and loose sections of trail.

2021 trek rail 9 emtb bosch

Speaking of traction, there’s bags of that courtesy of the aggressive Bontrager SE5 Team Issue tyres. These feature reinforced Core Strength casings, dual compound rubber, and plenty of volume – they measure up slightly larger than claimed at 2.63in wide. Initially Dan set them up with higher pressures, but that made them feel overly stiff and uncompliant. The robust casing means the SE5s is happier at lower pressures, allowing them to more easily contort to the trail surface rather than bouncing off of harsh edges.

Perhaps the only problem with the Rail’s warp-speed capabilities is that it’s often possible to come into sections too hot. In these situations, where the trail tightens up on you a little quicker than anticipated, there are times where it feels big. However, the grippy tyres, combined with the fact that the back end isn’t obscenely long (448mm), does mean you can wrestle it back into line.

2021 trek rail 9 emtb bosch
Find a lip, pick a landing. Any landing.

It’s otherwise a very forgiving bike. Bacon was saved on numerous occasions, either while bombing down blown out rutted moto trails blind, or when a jump was mistimed. On one specific ride, where Dan was lapping the bottom section of the Epic trail at Mt Buller, he came into a bonus double without nearly enough speed. At that point all he could do was pull up on the bars, hold on, and hope for the best. The Rail’s suspension soaked up the cased impact without drama, avoiding what would have otherwise been a pretty horrible crash. Muchos gracias, Trek Rail.

2021 trek rail 9 emtb bosch
Traction control is superb thanks to the sensitive suspension and those big 2.6in tyres.

But it’s no heffalump

Given this bike’s high-speed tenacity, somehow the Rail never feels unwieldy. This was the same magic we found in the Slash – a very capable enduro bike that’s still totally comfortable on more mundane trails. Yes we’re talking about a 24kg e-MTB here, but aside from the occasional tight off-camber corner, it never feels overly cumbersome.

Trek has exercised some restraint in the Rail’s geometry – the wheelbase is long, but not ridiculously so. On the flatter, more adventure-based rides we took it on, it was plenty comfortable with good weight distribution. It doesn’t force a load of pressure through the grips, and it also doesn’t demand a whole lot from its pilot either.

2021 trek rail 9 emtb bosch
We took the Rail on some longer, more pedally all-day adventures – this bike isn’t just about riding super technical trails.

On those longer and more pedally rides, the Bosch motor delivers a smooth transition past the 25km/h cutoff, and there’s very little drag through the cranks as you continue to spin. Of course at that point you’ll rudely be made aware of the overall weight and chunky 2.6in tyres.

You do get a tonne of traction when the trail points upwards though, with the Rail impressing on steep, technical climbs. The stated seat angle is listed at 75°, though shoving the saddle forwards on the rails helps to steepen it further, closer to 77° in our case. You can also flip the Mino Link in the rear rocker link pivot to steepen the angles by another half degree. We didn’t bother though, as the climbing position was fine, and we preferred the lower centre of gravity in the Low position anyway.

2021 trek rail 9 emtb bosch
The Bosch motor offers plenty of punch for steep climbing, and the Rail’s traction-rich back end helps to make the most of it.

The 448mm chainstay length is also nicely balanced for a long travel 29er. Some brands are going shorter (and resorting to mullet setups) for more manoeuvrability on regular singletrack, while others are going longer for vertical wall-climbing capability on more rugged hiking/moto trails. Trek seems to have split the difference with the Rail, and it offers a nice compromise as a result.

Sure, a mullet setup will naturally deliver a more carveable ride experience. Bikes like the Merida eOne-Sixty or Canyon Spectral:ON offer a poppier and more sprightly ride quality on purpose built trails, especially for shorter riders. But there’s no denying that the Rail’s full 29er setup does provide more traction and stability, and it maintains momentum better on rough terrain – both on the ups and the downs.

Strong, responsive power delivery

The climbing performance is made all the more pleasurable on the Rail thanks to the smooth and rapid engagement from the Bosch Performance CX motor. The combination of finely-tuned speed, cadence and torque sensors give the motor excellent pickup that reacts quickly to the slightest pedal pressure, highly useful on very steep and technical singletrack.

Also useful is the extra couple of seconds of power delivery that you’re provided when you stop pedalling. This overrun feature is ideal when you need to take a moment to rest on a techy climb, allowing you to briefly lean on the motor while you catch your breath. It can be a little surprising at first, but once you’re used to it, it becomes a welcome tool in the Rail’s climbing arsenal, providing a noticeable advantage over the smaller and lighter Shimano EP8 motor.

2021 trek rail 9 emtb bosch
The Bosch’s overrun feature keeps the rear wheel turning for a few moments after you stop pedalling, ideal for that extra push.

There is the usual clacking noise from the internal clutch mechanism, which is noticeable when freewheeling over rough terrain. While it would be nice if this noise wasn’t there, it appears to be the tradeoff for the reduced motor drag. And once you realise the noise isn’t signifying an actual problem, it doesn’t take long to tune it out, as Dan did after the first few rides.

Otherwise the Bosch motor stands as one of the best power-plants currently on the market, thanks to its powerful response and strong torque. Being a powerful rider himself, Dan mostly left the motor in the Turbo assist mode to quickly gain access to the motor’s full output when needed. This differed from Wil’s experience with the Cube Stereo Hybrid 160. Being a lighter rider, he preferred using the less aggressive eMTB mode. That said, the Rail delivers so much traction from its supple suspension and big volume 29er tyres that it’s much better placed to harness the motor’s full power output, with less risk of wheel-spin and the bike pulling your arms out of their sockets.

Still, the eMTB mode is the one that will suit most riders thanks to its more flexible and adaptive feel. Of course you can also gain considerably more range by using the eMTB Lite mode (which we preferred over Eco) for longer rides where you’re pushing north of 1,500m of climbing.

Off the beaten track

We’ve had some amazing experiences while riding the Rail over summer, including a visit to some of the more remote areas beyond Mt Buller. A particular highlight involved an all-day adventure with a 20km ride up the valley, bikes then stashed in the bush, followed by a 25km round hike in the high country, before picking the bikes up and riding back down to the valley floor.

In between nightshifts working as a fireman in Melbourne, Dan’s also used his free mornings to go exploring beyond the city limits in areas which aren’t typically popular with mountain bikers, but frequented rather by hikers, 4WDs and dirt bikers. The Rail, with its generous 625Wh battery pack, has lapped up these e-MTB exploration missions, thriving on being thrown deep into the bush down steep, rutted, blown-out fireroads that you wouldn’t dream of tackling on a regular bike, or even on foot for that matter. In these often mobile reception-free zones, it does make you reconsider what you carry with you on a solo bike ride though – Dan’s added an Epirb, a first aid kit and snake bite bandages to his usual riding kit.

Longterm living

While there is plenty to be impressed about on the Trek Rail, there are less than impressive attributes too.

The remote switch looks clunky on what is a $10K mountain bike. The walk mode is also awkward to use, as it reduces your grip on the bars while you hold down the button at the top of the controller with your thumb.

We do like the Kiox display though, which offers a nice colourful screen that displays a tonne of data at your fingertips. Each mode has a different colour so it’s easy to tell what setting you’re in, and you can quickly check battery percentage and your estimated remaining range. Trek’s decision to mount the display on the top tube is also a good one – it puts the screen out of your immediate field of view, so it’s totally unobtrusive. It’s also less likely to get damaged in a crash.

It is easy to remove due to the magnetic attachment, but make sure you don’t lose it – without it the bike won’t turn on. It never happened to us, but there’s potential to knock the head unit off during a crash.

2021 trek rail 9 emtb bosch
We’d love to see a more discreet controller, like what Specialized uses on the Levo.
2021 trek rail 9 emtb bosch
The Kiox head unit is a neat display though. Just don’t lose it – the motor won’t turn on without it!

Otherwise the electronics are nicely finished, and it’s great to see the speed sensor discreetly integrated into the dropout, with a magnet attaching directly to the rotor. The spring-loaded latch for the main charge port hasn’t caused any issues, and you’re able to charge the battery both in or out of the bike.

Speaking of the battery, we did have an issue with it coming loose on one ride, causing one heck of a rattle inside the downtube. It turned out the upper battery mount had come loose, which was not ideal. It was particularly not ideal because Dan didn’t have the special battery key with him in his riding pack, which meant he couldn’t remove the battery to tighten up the mount. After getting home, he was able to release the battery, tighten up the mount, and it hasn’t caused an issue since. Still, this is another reason why Bosch needs to use a normal hex key for releasing the battery, as the key is just another thing to remember and potentially lose.

Component highs & lows

For a big e-MTB that’s as hungry for speed as the Rail, it’s fantastic to see big SRAM Code R brakes. While the rear is in need of a bleed, they otherwise haven’t caused an issue throughout testing, offering gobs of stopping power – props to Trek for spec’ing a 200mm rear rotor and a 220mm whopper up front. Bold!

The GX Eagle 1×12 drivetrain has been solid too, and there’s plenty of usable low-range grunt with the big 52T sprocket. Dan did manage to break a chain early on, which was a scary experience – luckily he wasn’t too far from home. Spare master links and a chain breaker now live in the kit bag permanently.

2021 trek rail 9 emtb bosch
Keep an eye on the rear thru-axle, ours came loose on one occasion.

Another random mishap occurred when a 532 error code appeared on the Kiox display, rendering the motor inactive as a result. Some Googling later revealed this was due to the speed sensor not picking up the magnet – a result of the rear thru-axle having come a little loose. This isn’t the first time we’ve had a thru-axle work its way loose, but it’s a timely reminder to check them periodically to make sure they’re always snug.

Otherwise everything else is still in one piece, including Bontrager’s Line Comp 30 wheelset. These feature Rapid Drive hubs with 54 engagement points, though for $30 AUD you can get a pawl kit to upgrade them to 108 points of engagement. The TLR rim strips provide secure tubeless setup, and overall the wheels have been pretty bulletproof, despite being run insert-free.

The tyres have also gone through the whole test period without a single puncture (you all know exactly what’s going to happen now…). Impressive given they’ve been given an absolute hammering, and that they’re actually not that heavy with a claimed weight of 1,080g per tyre. That’s considerably lighter than a Maxxis DoubleDown or Schwalbe Super Trail tyre.

2021 trek rail 9 emtb bosch
All those updates have made a considerable improvement to the Rail’s performance and all-round usability. This is a ripping e-MTB.

Flow’s Verdict

When we first swung a leg over the Trek Rail at the launch back in 2019, we were impressed with the balanced geometry, high quality suspension and responsive Bosch motor, which gave it genuine all-round talent. With this new model however, Trek has elevated the performance significantly thanks to the addition of the custom Super Deluxe shock and beefier ZEB fork, which give the Rail a whole new level of ploughability. Add in the confidence-inspiring handling, big 29in wheels and chunky 2.6in tyres, and you’ve got a serious amount of control and traction on tap for descending full-blown downhill trails.

The Rail doesn’t place all of its eggs in the descending basket though – those same attributes make it a great technical climber, and it’s surprisingly comfortable and easy to manage on less demanding all-day adventure rides too.

Value for money isn’t outstanding, particularly when you compare the Rail 9 to the likes of Merida and Norco. Pricing is on par with Specialized though, and you are getting a very robust, well-considered package here with big brakes, superb suspension and that powerful Bosch motor. The new Kiox display is aesthetically pleasing and well-placed, though we’d like to see some refinement to the controller. Otherwise we love the overall feel and power delivery, which complement the Rail’s technical prowess well.

For riders on the lookout for a big travel, ride-everything e-MTB that delivers outstanding traction and high-speed control, the Trek Rail is a seriously capable option to put on your list.

2021 trek rail 9 emtb bosch
2021 trek rail 9 emtb
Rocks quiver at the sight of the Rail.

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