More of a DH shuttle bike that backcountry explorer

Product Overview

BMC trailfox AMP SX


  • Solid build kit with no obvious weakness


  • The 500Wh battery is the limiting factor
  • Only available in three sizes


BMC Trailfox AMP SX: first ride review


Price as reviewed:


BMC Trailfox AMP SX gets the treatment to make it more gravity focused. A 170mm Fox 36 fork slackens the head angle and gives you 20mm more travel up front.

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BMC Trailfox AMP SX need to know

  • DH casing 2.5in Vittoria Mota tyres are mounted on wide 27.5in DT Swiss e-bike wheels.
  • Shimano STEPs E-8000 drive system is powered by a 500Wh internal battery.
  • £7,499
BMC Trailfox AMP SX

SX makeover proves its value on the downhills

E-bikes are evolving at a blistering rate, but it doesn’t always take a wholesale change to the power supply to uprate an e-bike to the next level.

Take the latest addition to the BMC Trailfox AMP family, for example. By upping fork travel to 170mm and adding powerful Magura MT7 brakes, the SX version of the Trailfox AMP has its party mode cranked up to 11.

BMC Trailfox AMP SX

STEPS motor runs on a 500Wh battery

OK, so the Shimano STEPs E-8000 drive system doesn’t have party mode, just Eco, Trail and Boost, but with all of the changes to the specification and the knock on effect the taller fork has on the bike’s geometry, the focus of the Trailfox AMP SX has definitely shifted toward gravity fuelled riding.

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Just take a look at the cockpit, the ultra wide 800mm Rental Fat Bar and stubby 40mm Apex stem are indicative of the new flat-out focus.

BMC Trailfox AMP SX

Eco, Trail and Boost modes are accessed from a bar-mounted remote

This shift in attitude is probably best reflected in BMC’s choice of rubber though. The Trailfox AMP SX is still rolling on 27.5in wheels, but these are now shod with 2.5in Vittoria Mota DH tyres instead of the lighter casing 2.8in Maxxis tyres found on the other models in the range.

Granted, the Mota tyres add to the overall weight, but the stiffer casings allow you to run slightly lower tyre pressures for increase grip, without having to worry about punctures or the durability of the tyre sidewalls, which tend to wear out pretty fast on e-bikes.

BMC Trailfox AMP SX

On-trend stubby 40mm Apex stem

The 2.5in tyres also drop the BB height a hair for increased stability, not that the Trailfox needs it. In fact, with less pop coming from the smaller volume, stiffer casing tyres, setting up the Factory level Fox DPX2 shock to have faster rebound and less compression damping helps make the bike feel more lively.

Unfortunately, the softer compound, moto-stye tread also increase the rate at which you burn through the juice of the 500Wh battery housed inside the Twin Hollowcore downtube on the monocoque carbon front end.

So you really need to be conservative with your power use, reserving Boost mode for those moments when you need an extra jolt of energy to rocket up the steepest climbs. As such, gradual fire road ascents followed by steep, rowdy descents are this bikes calling card. Making the Trailfox AMP SX more of a DH shuttle bike that backcountry explorer.


For a bike with a Shimano E-8000 pedal assist motor you may be surprised to discover that it’s actually gravity that’s needed to really make the Trailfox AMP SX spring to life. On more mellow trails the SX feels clumsy and awkward, and you really notice the added weight of the burly build making it harder to accelerate and manoeuvre the bike. Get it on anything where gravity is acting in your favour though and the SX build make a lot of sense and much like a DH bike, speed really is your friend here.


Frame:Carbon/aluminium, 150mm travel
Shock:Fox Float DPX2 Factory Evol
Fork:Fox Float 36 Factory FIT4 E-MTB, 170mm travel
Motor:Shimano STEPs E-8000
Battery:Shimano STEP E-8030 500Wh
Display:Shimano STEPs E-8000
Wheels:DT Swiss H1900, Vittoria Mota DH 27.5x2.5in tyres
Drivetrain:Shimano E-8000 34t chainset, Shimano XT r-mech and SLX shifter
Brakes:Magura MT7 200mm
Components:Rental Fat Bar 800mm, Apex 40mm stem, Fox Transfer Performance Elite 150mm post, WTB Silverado Comp
Sizes:S, M, L
Size tested:L
Head angle:65°
Seat angle:74°
BB drop:17mm
Chain stay:445mm
Front centre:791mm
Top tube:645mm