Trek Powerfly 5 Review

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When it comes to hardtail electric mountain bikes there’s an awful lot of choice (if they’re in stock) from the big name manufacturers. When one of my friends called me last week to say he’d brought a Trek, I was eager to try it out. In this Trek Powerfly 5 review I will take a closer look at the specifications and share with you my opinions after spending a couple of hours with it on Bodmin moor.

trek powerfly 5 review


Trek’s mountain bike heritage goes all the way back to 1983 when they released the 850 – fast forward 28 years and they have a comprehensive range of high-end e-MTB’s ranging in price from just over £2500 all the way to up to an eye-watering £11500.

At £3750 the Trek Powerfly 5 sits at the upper end of their hardtail range and benefits from the latest Bosch Performance Line CX motor with 625Wh battery. The Powerfly 5 also boasts Rockshox forks and SRAM Eagle SX 12-speed drivetrain.

trek powerfly 5
The 2021 Trek Powerfly 5 Image courtesy of Trek Bikes (GB)

My friend had been talking about upgrading his Cube Acid hardtail e-MTB for some time and we’d previously discussed the merits of the Trek. He recently took the plunge and purchased the bike reviewed here.

First impressions

The first thing that struck me about the Trek Powerfly 5 was how stunning the paintwork finish is – it’s an absolutely gorgeous bike in the ‘slate/volt’ colour scheme. Mind you, you’d expect nothing short of this on an e-bike costing more than a decent second hand car!

trek powerfly 5 pictured on bodmin mor

Although the 17″ frame was a bit on the short side for me, with the seat post properly adjusted it actually felt quite comfortable. My friend paid an extra £200 to have the optional Bontrager dropper seat post fitted, which is a must if you’re going to be tackling the trails.

Riding some rock-strewn single track the Trek feels sure-footed. For an older rider like me, the Powerfly 5 inspires confidence (maybe a bit too much) and is great fun to ride. Where this e-bike really comes into its own is when the trail turns upwards – it’s not the first Bosch CX I’ve experienced but this motor never fails to impress me with its 85Nm of torque. Riding up steep tracks is helped even further by the trail-busting SRAM Eagle 11-50 12-speed rear cassette, meaning you never run out of gears.

trek powerfly 5 electric mountain bike

Although my ride was fairly brief I was thoroughly impressed with the off-road abilities of the Trek, it’s a great all-round package suitable for beginners, intermediate or the older more experienced cyclist who’s returning to mountain biking after a long break.

Below I will go into more details on the components.

Electric components

The high-end mountain bike world is dominated by either the Bosch CX, Shimano Steps E8000 / EP8 and Brose motors. It’s good that manufacturers recognised the demand for greater battery range and the Trek Powerfly 5 comes with the Bosch 625Wh powertube battery which is neatly integrated in to the frame.

Bosch Performance Line CX

bosch performance line cx motor as fitted to the kona electric ute

The Bosch Performance Line CX motor benefits from several upgrades over the previous model, most notably the 85Nm torque output offering the rider up to 340% assistance.

There’s the new Extended Boost mode which makes negotiating rocks and exposed roots on the trail much easier, particularly uphill. This means the bike can be manoeuvred with greater agility on technical sections.

bosch performance line cx motor

Revised e-MTB mode – This ensures the rider is well-prepared for whatever situation the trail has in store. New sensor and motor control functions give mountain bikers a much wider range of dynamic and natural support.

The Bosch motor is smooth and whine from the motor is quiet and not intrusive. Performance is as good as you will find on a road-legal e-MTB and it adds a whole new dimension of fun when riding off-road.

625Wh Powertube battery

bosch powertube 625 battery

I first rode an e-bike with the 625Wh battery at the end of 2019 and having the extra capacity will ensure riders can spend more time enjoying the trails. Range will really depend on lots of different variables but 50 miles should be achievable when riding off road – check out the Bosch range calculator for a rough estimate of battery range from the 625Wh battery.

Bike components

Quality components are a must on electric mountain bikes at this price point and the Trek Powerfly 5 doesn’t disappoint. I have gone into more details on the specification below.


trek powerfly 5 with sram 12 speed gearing

The gearing is comprised of SRAM Eagle single-click 12-speed shifter with an NX Eagle rear derailleur and 11-50 cassette – as the Bosch uses an ISIS type crank interface, a SRAM X1 crankset is fitted. The drivetrain is finished off with a high quality SRAM SX Eagle chain.


Braking is provided by the excellent Shimano MT-420 4-pot calipers with 203mm brake rotors – as expected these brakes work really well and will provide more than enough stopping power for most riders. I found them to be excellent, and you only need to use one finger for braking.


If found the 120mm Rockshox Recon RL suspension forks worked very well indeed. Although they are at the lower-end of Rockshox forks they feature trickle down technology from more expensive forks and feature Motion Control™ damping which features low speed compression adjustment to lockout.

Wheels and tyres

The wheelset is a disc-specific Bontrager Kovee Comp 23 with Boost 110, 15 mm thru axle at the front and a Boost 148, 12 mm thru axle at the rear. Tyres are Bontrager XR3 Comp, wire bead, 30 tpi, 29×2.30″ which seemed to handle the damp moorland trails very well. If you wish to upgrade to a tubeless set-up these wheels are tubeless ready. The hub is a standard 9/10 speed Shimano freehub.

Frame and finishing kit

For the frame Trek use their Alpha Platinum Aluminium which is their premium lightweight aluminium designed for maximum strength and minimum weight. As I’ve mentioned above the finish is exquisite and looks incredibly hard wearing.  The frame also benefits from internal routing for lights (should you choose to fit them) and a direct kickstand mount.

All of the finishing kit is all by Trek’s in-house brand Brontrager which is excellent quality. This bike also had the optional Bontrager Line Dropper seat post fitted which costs an additional £199.99.


If I was in the market for a capable hardtail electric mountain bike I’d be very tempted by the Trek Powerfly 5. It’s great fun to ride and feels very capable on rough single track – the handling inspires confidence and that Bosch motor is the icing on the cake!

There are cheaper options available and if you’re new to electric mountain biking you may not want to spend quite so much on your first purchase.

trek powerfly 5 white

Having said that, if I had the money to spend on a nice hardtail e-MTB the Trek would certainly be on my shortlist. Other plus points are the excellent brakes, SRAM 1 x 12 gearing and the 625Wh battery.

My friend has brought this e-bike with the intention of keeping it for a good few years and I’ll post any relevant updates here.

Thanks for reading and if you have any questions or comments please leave them below.


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Trek Powerfly 5 2021


Value for Money




Battery Range



  • Excellent 4th Gen Bosch CX Motor
  • 625Wh battery
  • Top quality components


  • A bit on the pricey side


Passionate E-Bike advocate and enthusiast. 5 years experience converting bikes for customers primarily using Bafang and Tongsheng electric bike motors.

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