Pedal-assist mountain bikes have been making inroads into the mountain bike world and year-on-year they get closer to feeling like a ‘real’ or ‘normal’ mountain bike. True believers in the e-MTB experience expect that pedal-assist bikes will be in the majority of new bike sales in the coming years. It’s already the case in some countries.

Trek have had the Powerfly hardtail model in their line up already, but they have just released the new Powerfly FS. Globally, Trek have 130mm travel models and 150mm ‘LT’ models – but here in Australia we have the Powerfly FS 5 and 7 to play with. With 130mm travel front and rear, and a Shimano 11-speed group set, the Powerfly FS 7 may be the ticket to opening new doors for some riders, and increasing the boundaries for others.


A few things stand out when looking at the Powerfly FS. Firstly, it’s really big. With plus tyres, a chunky alloy frame, and modern, slack trail geometry, the Powerfly is a big bike. But it’s also a good looking bike, as the battery is integrated into the frame. This was a point that Trek’s engineers worked hard on with Bosch - also integrating a handle onto the battery so it’s easy to remove when it comes time to charge. The position is more than aesthetic, as it allows the weight to sit lower in the frame, which is key for the handling of the bike.

Bosch also provide the Performance CX motor and have partnered with Trek to create a new power setting. Instead of the usual off, Eco, Tour, Sport and Turbo, there’s now an ‘eMTB’ setting to replace the Sport setting that fluctuates the amount of power, depending on how much torque is going through the system. So if you’re just chilling out, it does as well. If you’re giving it some beans to get over a pinch climb, the motor does the same. Trek’s research had shown that riders on e-MTBs tended to use the power settings instead of gears to go faster, and this setting gets you back to using the gear range, and riding the bike much more like a non-pedal-assist mountain bike. As a bonus, it also helps prolong battery life.

The setting provides a maximum torque of up to 75Nm, and will deliver 120-300% times the output of the rider. So at the highest level, it really does get you moving. Of course, the units are speed limited to 25km/h. So the gains in speed are on the flat, accelerating, and (most crucially) when you’re pointing back up hill. E-MTBs are the self-shuttling dream.

Trek have specced the Bosch PowerPack 500 battery, which has 500Wh (Watt hours), the longest running battery Bosch produce. That also means they have a longer charge time of 4.5hrs, although they do get half the charge in 2hrs.

As for the rest of the bike, the geometry and suspension design really mimics the Trek Fuel EX. A lot of your expected features are here, like the MinoLink to adjust geometry, internal cable routing, and the KnockBlock headset, which limits the movement of the fork so the bars can’t swing around and take out the top tube. The frame has great standover height as well, a nod towards the sort of riding the Powerfly is intended for.

Trek have been smart to implement a few other spec changes, like using 32 hole rims that are not only wider, but stand up to impact tests normally reserved for downhill wheels. E-MTBs are heavier, and you do end up riding them hard downhill – so this is a spec change in response to rider habits. The 40mm units from SUN-Ringle let the Schwalbe 27.5 x 2.8” plus tyre bag up nicely.

Setting up the bike is like any other, but it’s really worthwhile making sure you’re sitting comfortably. Bikes like the Powerfly FS are pedal-assist. If you’re not pedalling, there is no assistance. So you need to make sure your position is dialled. I set the bike’s RockShox suspension up with 30% sag, as recommended by Trek’s suspension guru Jose Gonzalez. All the Powerflys (and non e-MTB trail bikes) have a new version of RE:aktiv suspension too. Head to for more details on that.


This test was done at altitude in big mountains, and I was happy to be on a pedal-assist bike. The design-brief behind the Powerfly was to meld the usual mountain bike riding experience with pedal-assist like no e-MTB before it. With a frame based on the Fuel EX with 130mm of travel, a lot of the riding characteristics are the same, if you were to be comparing the bike to a Fuel EX Plus model anyway. The key differences are the wheelbase, which is about 6cm longer, and the majority of that is in the chain stays.

While the test took place in a foreign country, I had ridden the trails before, and rode them again later in the trip on a Fuel EX too, so it was interesting to see how riding on a pedal-assist bike made a difference. In this case, using the eMTB setting was a big step towards a normal ride feel. If you’re putting in, it helps out more. Having ridden e-MTBs where sometimes the assistance is unwanted, like in technical terrain, this was a huge improvement. Personally, it took the e-MTB experience from one I understood, to one I enjoyed.

The eMTB setting on the Bosch motor means the Powerfly reacts as you would expect. It doesn’t surge out of corners or put too much power down on wet roots, instead it reacts more like you do. Given the bike does have plus sized tyres, there is plenty of traction on offer - which helps. And you do tend to ride differently and not pedalling almost acts as a brake once you get used to the assistance. This does mean you have to take a different tact as well, and pedal up climbs as much as possible. Choosing your line, and pedal stroke, is crucial. A long-term shift to shorter cranks must be coming to e-MTBs.

While e-MTBs are big help in getting up high without the same strain, the reason more and more are on the market in 130-150mm models is because it really is about more smiles pointing down. I think the Powerfly really worked best in the low setting on the MinoLink, as even if the position is a little sluggish going up – you have the assistance. The bottom bracket was 6mm lower but knocking the head angle half a degree back to 66.9 was worth it.

There is no denying that e-MTBs like the Powerfly FS are heavy – downhill strength rims, plus tyres, motors, batteries – these things add up. But coupled with strong brakes and the right suspension set up, the bikes really do haul when pointed down hill. The heavier bike tracks so well, and I was happy taking rougher lines with more requirements to jump, and pushing deeper into loose berms as the combination of the plus tyres, weight down low and supple suspension gave me the confidence to do so.

Although Trek really feel the eMTB selection on the Bosch motor is the ‘do everything’ setting, I personally preferred the eco setting on long downhills. I think here in Australia on terrain that is less steep I might feel differently, but with such ready acceleration thanks to gravity on the steep trails in Verbier Bike Park, I preferred less input from the motor, and more from myself.

The brakes and shifting do take a pounding with the extra weight and pedal-assist. 200mm rotors help the Shimano Deore brakes on the Powerfly FS 7, but if I was riding this bike a lot in big hills, which are easier to access on a bike like this, I’d think about something like the Saint brakes. Similarly, as much as you think you back off the load when shifting, the motor does keep load on there as well. I had no shifting dilemmas on the Powefly FS 7 but I don’t think you can expect a long lifespan from the Shimano SLX parts. I’ll be interested to see if Shimano bring out an e-MTB group set like SRAM have with EX-1.


The big question here is, do you want an e-MTB? If there are hurdles for you to deal with before you consider throwing a leg over one – then you are unlikely to have read this far. But, as e-MTBs go, the Trek Powerfly FS 7 hits a lot of the key requirements. It is based on a great trail bike (the Fuel EX) but bettered by having the right spec and design changes made for e-MTBing. Far from being a Fuel EX with a motor attached, minor geometry changes and immense structural and spec changes make it a bike that helps you get up hill and along the flat, then lets you charge downhill. The LT 150mm version available overseas will do that even more.

My time on the Powerfly FS 7 was fun. I rode with lots of other people on e-MTBs from various parts of the world, and the pedal-assist meant that even though we were on steep terrain, at altitude, we could share stories, share the riding buzz, and no-one felt overwhelmed by the environment we were in. It was different to riding a non-powered mountain bike. Not better, not worse. I had a whole lot of fun and didn’t feel too beaten up at the end of the day. And I think a lot of people will appreciate that.

MODEL Powerfly FS 7
RRP $6499