By Paul Norman

Published: Sunday, 31 July 2022 at 12:00 am

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With the launch of the new Trek Fuel EXe, Trek has two full-suspension electric mountain bikes with similar travel and geometry, but very different rides – so what’s the difference?

Whereas the Trek Rail is a full-assist eMTB, ready to take on almost any trail you can throw at it, the Fuel EXe aims to provide mid-level assist, replicating the more natural feel of a regular mountain bike.

That’s reflected in the motor and battery systems used across Trek’s two electric mountain bikes. Different torque outputs, motor configurations and battery capacities result in two bikes that open up new opportunities for mountain bikers who want to add some assistance to their ride.

The new Fuel EXe is designed to offer progressive assistance on the ups, thanks to 50Nm of torque from the TQ motor, without losing any of the familiarity of a regular trail bike. The compact motor makes it look like a non-assisted bike, too.

The Rail, on the other hand, is Trek’s heavy-hitting electric mountain bike, with a powerful Bosch motor delivering 85Nm of torque, making this a machine ready to eat up all terrain.

Let’s delve deeper into how the Fuel EXe and Rail compare in the Trek line-up, from their frames and motors, to suspension travel, geometry and more.

Frame material

Unlike the Rail, the Fuel EXe comes with just one full-carbon frame option.

In contrast, there are both carbon and alloy Rail frames, with the geometry and features differing between the higher-spec carbon Rail 9 and the alloy Rail 5 and 7.

We’ve concentrated on the carbon Rail 9 here, to provide the closest comparison with the carbon fibre Fuel EXe.

Trek

Motor

Steve Behr / Our Media

The biggest difference between the two bikes – and ultimately how they ride out on the trail – is in the two motors used: the TQ HPR50 on the Fuel EXe and the Bosch Performance Line CX on the Rail.

The Fuel EXe uses a completely new motor from TQ, a brand that’s relatively new to electric bike motors but has extensive experience in robotics, aerospace and other fields.

Called the HPR50, its peak output figures are 300 watts and 50Nm of torque. That’s less torque than the 85Nm offered by the 250-watt Bosch Performance CX Line motor in the Trek Rail, but still more than some lighter-weight eMTBs from other brands, hence Trek’s ‘mid-level assist’ classification.

Trek

The Fuel EXe’s HPR50 motor weighs around 1,850g and also has a very small form factor. It takes up relatively little space around the bottom bracket shell, so the bike’s geometry is close to that of a non-assisted trail bike, while its Q-Factor of 135mm is close to a pedal-powered bike, too.

Trek says the TQ HPR50’s design means it turns more slowly than other ebike motors and there are no belts and gears, so it’s quieter and there’s less to go wrong. There’s fast pick-up when pressing on the pedals, with no lag for a natural ride feel. There are three power modes (along with a walk mode), selected via a small bar-mounted controller.

Trek

All this is designed to offer an eMTB that keeps things simple – from the low weight and compact motor integrated into the frame, to the familiar geometry and a level of assistance that bridges the gap between non-motorised bikes and conventional eMTBs.

Think of it as a trail bike, but one that’s ready to step on the gas when you need it to.

Bosch

In contrast, the Rail ups the ante with a more powerful Bosch Performance Line CX motor, with a maximum torque of 85Nm. It weighs 2.9kg and has five different modes, with up to 340 per cent support, so you’re never going to be left short.

It has a latest-generation Bosch Kiox display mounted on the top tube and is controlled by a thumb-operated remote mounted on the bars, which also has LEDs to display the assistance level.

Trek

It’s part of Bosch’s Smart System, an integrated suite of motors, batteries, controller and phone app enabling you to fine-tune your motor setup.

The Rail’s motor provides all the punch you’ll need, for more power, wilder terrain and, as we’ll come on to, bigger range.

Battery

Trek

As well as a more powerful motor, the Trek Rail also has a larger-capacity and heavier battery.

The 750Wh integrated weighs 4.4kg, offers tool-free removal from the frame and includes a carrying handle. It’s Bosch’s largest-capacity battery and has fast charging, reaching 50 per cent charge in just over two hours.

Trek says you’ll get a range of around three hours on difficult terrain and five hours, or 50 miles, on smoother trails.

In contrast, the Fuel EXe has a lighter internal battery with 360Wh capacity – roughly half that of the Rail’s. It’s also removable, but you’ll need to unscrew two Allen bolts to remove the covering plate next to the bottom bracket.

Trek says the battery weighs 1,834g and sits in a down tube that’s 34 per cent smaller than the Rail’s. If you want more range, you can add a 160Wh bottle cage range-extender battery, which plugs into the top end of the down tube.

Charging time for the Fuel EXe’s main battery is claimed at around two hours and it’s charged up in priority over the range extender if this is also being used.

The battery is good for between two and five hours of riding, with the range extender upping that by around 40 per cent.

Connectivity

Trek

Trek has a completely new app for the Fuel EXe, which enables you to customise assistance levels and other motor parameters. Called Trek Central, the app also learns from your riding style to hone its estimates of how much range you’ve got left in the battery.

There’s also a display in the top of the top tube that gives you info on battery life, range and other data.

Steve Behr / Our Media

The Rail, in contrast, uses the Bosch eBike Flow app to monitor motor performance and, like the Trek Central app, lets you alter its support dynamics and power output levels to suit your riding style. It can track your ride stats, with automatic recording once you start to ride.

Suspension travel

Steve Behr / Our Media

As an eMTB pitched at trail riding, the Fuel EXe has 140mm of suspension travel at the rear, paired with a 150mm-travel fork. It uses Trek’s Active Braking Pivot (ABP) system, designed to isolate braking from the suspension mechanism.

If you want more travel, there’s also scope for burlier upgrades, because the frame is designed to take a 160mm fork and coil shock. Lightweight eEnduro anyone?

Trek

The Rail, meanwhile, gets an extra 10mm of rear travel at 150mm, and like the Fuel EXe, also includes ABP tech in its rear triangle. There’s 10mm more front travel too, with a 160mm-travel fork fitted across the range, making the Rail primed for aggressive riding.

Like the Fuel EXe, the suspension’s main pivot has been moved forward for more consistent anti-squat values.

Both bikes use the latest-generation RockShox or Fox forks and shocks, dependent on spec level.

Geometry

Steve Behr / Our Media

The Fuel EXe’s familiar and up-to-date geometry is intended to make it an eMTB that still feels nimble and playful on the trails.

There’s a 45-degree head angle to keep things slack and capable up front, with reach figures ranging from 427mm to 507mm.

On that note, the Fuel EXe has slightly shorter reach figures than the Rail, but other geometry figures, including head tube and seat tube angles, are broadly similar.

Both ebikes get Trek’s flippable Mino Link connector at the seatstay/rocker pivot, which enables you to alter the head tube and seat tube angles by around half a degree, and raise or lower the bottom bracket by around 7mm.

Wheel size

Steve Behr / Our Media

Both the Fuel EXe and Rail come stock with 29in wheels, but in both cases the Mino Link, when run in its high setting, gives you the option to swap in a 27.5in wheel at the rear if you want to run a mullet bike configuration.

Specs

Trek

The new Trek Fuel EXe range consists of six models, while there are 11 Rail bikes, of which five have the new 2022 carbon frame, Smart System motor and geometry.

The top-spec 9.9 XX1 AXS model of the Fuel EXe gets a RockShox Lyrik Ultimate fork, which fits the bike’s more trail-focused intentions, whereas the similarly range-topping Rail 9.9 XX1 AXS gets the burlier RockShox ZEB Ultimate Charger 2.1 fork.

In both cases, there’s an AirWiz digital pressure monitor, plus there’s an AirWiz on both bikes’ RockShox Super Deluxe Ultimate shocks.

Trek

Both top-spec models roll on the same Bontrager Line Pro 30 carbon wheels with 2.5in Bontrager SE5 or SE6 Team Issue tyres.

Elsewhere, Trek Fuel EXe prices range from £5,750 / $6,500 / €6,500 up to £13,250 / $14,000 / €15,000.

Trek Rail pricing runs from the alloy bike at £4,300 / $5,650 / €4,700 up to £12,600 / $13,800 / €13,600, with the carbon Rail 9 starting at £8,350 / $9,200 / €9,100.

Which is best for you?

Sterling Lorence / Trek

In launching the Fuel EXe, Trek has created a new category of ‘mid-level assist’ electric mountain bike within its range, aimed at providing a quiet, lightweight and agile ride, akin to a non-assisted trail bike.

The Rail, meanwhile, remains as Trek’s no-holds-barred eMTB for tackling more rugged terrain, with more power and battery capacity on tap.

That’s demonstrated by the 50Nm of torque from the TQ motor, as opposed to the 85Nm provided by the Rail’s powerful Bosch motor.

In terms of weight, the Fuel EXe in a size medium comes in at around 19kg, while the Rail 9 comes in at around 24kg, so you’re saving some 5kg by going for the new Fuel EXe.

Trek

Which bike works best for you will depend on your aims – and the type of riding you do.

If you’re into tougher terrain and want the powerful assist to get you to the top quickly, then the Rail will do that for you and provide the range to keep you going. There’s also an extra 10mm of suspension travel.

If, on the other hand, flowy trails are your thing, and you’re happy putting in a bit more of the effort to get you up climbs, the Fuel EXe’s lower power output, lighter weight and familiar feel when pointing the bike downhill will be more your bag.

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