Trek's newest version of the Powerfly FS promises to be one of the best thought out EMTB's coming to market. Utilizing Bosch's latest integrated 500wh battery, intuitive EMTB mode and burly componentry better suited to the demands of assisted bikes and their increased speed and trail bashing brutality.
This Powerfly FS 9 is the 130mm travel machine, but there are also hardtails in the range, women specfic builds and the longer travel LT version with 150mm travel. The metallic silver FS 9 in question hits the shelves at €5999.
Frame Design Trek Powerfly FS 9 Details
• Intended use: trail / all mountain
• Wheel size: 27.5 +
• Rear wheel travel: 130mm
• Bosch CX motor
• 500wh integrated battery
• EMTB power mode
• MSRP: €5999
The new Powerfly features many of Trek's staple taglines and acronyms including the Active Braking Pivot, Mino Link and re:AKTIV shock technology. The frame also welcomes the integrated Knock Block headset and StraightShot downtube found on the Slash, integration continues with the Bosch battery being nestled inside the down tube. Integrated doesn't mean fixed, and with the security key, the battery can still be popped out of the frame easily for charging.Build
EMTB's take more beating than a standard mountain bike, so it's nice to see some added bulk on this Powerfly FS 9. Bontrager's specific Powerline 40mm wheelset has been strengthened to adhere to their downhill testing standard. The fork of choice is the beefed up EMTB optimized Fox 34, this means the steerer, crown, and stancions are stronger to cut down on fore-aft flex from the added bike weight. SRAM supply their Guide RE brakes with the bigger, older style Code caliper and the sterling EX1 drivetrain is the only sensible, but pricey choice if you have motor assistance.Geometry
EMTB's are not the same as normal mountain bikes, so it's good to see a lack of desperation from Trek to make their bike 'just like a normal bike.' Chainstays have deliberately been left lengthy at 474mm for climbing ease, the bottom bracket doesn't drag on the floor thus saving crankarms and pedals from continuous ground smashing and the front ends are roomy.
Our European team is currently putting a number of EMTB's through their paces and getting to grips with the nuances of these machines, so we won't go heavily in-depth here. But, the standout feature of the Powerfly for me was the super long chainstay and sensibly positioned saddle above the bottom bracket. With an extra few hundred watts of tireless power, EMTB's have a significantly different climbing characteristic than a solely human powered machine, this makes constant wheelie-ing and front wheel wander an issue on many bikes and the Powerfly is the closest so far to solve this issue. Secondly, the -24mm bottom bracket drop on the 130mm travel bike I rode cleared rocks and roots well, with an EMTB timing pedal strokes is more difficult due to the increased climbing speed and the need to keep the pedals turning to keep the motor spinning and engaged, lower is not better here.
Bosch's EMTB mode is a big winner too, and luckily for any early electric bike investors is available as a software upgrade to any Bosch powered bike. This mode gives you the best of all power levels – spin the cranks gently and it will give minimum assistance, employ some beans and the assist will shoot up to the maximum. This intuitive setting simplifies technical climbing by allowing the power assist to be manipulated on loose surfaces, around tight switchbacks and to boost up steep grades without changing modes.
SRAM's EX1 drivetrain is currently the only reliable choice for EMTB. The eight-speed system has the smoothest shifting action under power, the wide steps between gears mean fewer shifts while the motor fills the power transfer gap that human legs alone would struggle to span. The steel cassette and wider chain should add durability and the single gear change per push cuts down on clanging when trying to change 2/3/4 gears at once.
In general the Powerfly's spec is spot on, except the 60mm stem was dropped instantly, and the 750mm bar was narrow for us. The 2.8 Nobby Nic's from Schwalbe in their Perfomance casing are just asking to be punctured on a heavyweight EMTB, so we would swap these out too. Double Down casing plus-sized tires should be available soon from Maxxis and that would be our shout for something more durable and predictable.
Like all the EMTB's we are testing so far, descending is easy thanks to the huge stability and grip given by the added motor and battery weight. Even this 130mm travel trail bike has much more capability and confidence than an equivalent motorless bike. The Powerfly struck a good balance and we are looking forward to getting one in for deeper testing.
About the Reviewer Stats:
Age: 31 • Height: 6'1” • Ape Index: +4" • Weight: 75kg • Industry affiliations / sponsors: None • Instagram: astonatorPaul Aston is a racer and dirt-jumper at heart. Previously adding to the list of non-qualifiers at World Cup DH events, he attacked enduro before it was fashionable, then realized he was old and achy. From the UK, but often found residing in mainland Europe.