2021 Trek E-Caliber 9.9 XTR Review


Technical Specs & Ratings



E-Caliber 9.9 XTR


Class 1


Full Suspension



Hydraulic Disc



252 Wh

252 Wh

36.6 lbs / 16.62 kgs



Frame Details

OCLV Mountain Carbon Frame and Stays



Full Suspension


Fox Factory Air Suspension Integrated Into Trek ISO Strut, 60 mm Travel, Remote Lockout, Rebound Adjust Dial (1-12), 36 mm Stanchion with Kashima Anodized Coating, Boost 148 mm Hub Spacing, 12 mm Thru-Axle with Quick Release

Fox Factory 34 Step-Cast Float EVOL Air Suspension, 120 mm Travel, FIT4 2-Position Damper, 44 mm Offset, Remote Lockout, Rebound Adjust, 34 mm Stanchions with Kashima Anodized Coating, Boost 110 mm Hub Spacing, 15 mm Kabolt Thru Axle with 6 mm Bolt

Bontrager Kovee XXX, Carbon Fiber, ETRTO 622x29c, 50 PSI 3.4 Bar Max Tire Pressure, 24 Hole, Tubeless Ready | Spokes: Stainless Steel, 14 Gauge Bladed, Black with Nipples

Bontrager XR3 Team Issue, 29" x 2.40" (58-622), 50 PSI 3.4 BAR Max Inflation, Nylon


Knock Block Integrated, 62-Degree Radius, Cartridge Bearing, Tapered 1-1/8" to 1-1/2"

Bontrager Kovee Pro, Aluminum Alloy Main with Carbon Arms, 13° Rise, 60 mm or 70 mm Length, 35 mm Clamp Diameter, Blendr Compatible

Bontrager Line Pro, OCLV Carbon, 35 mm Diameter, 15 mm Rise

ESI Chunky, Silicone, Non-Locking, 125 mm Length

Bontrager XXX, OCLV Carbon, 0 mm Offset


Bontrager Montrose Pro, 7x10 mm Carbon Rails, 138 mm Width

NA, Trek Coquitlam Loaned me Bontrager Line Elite MTB Plastic Platform with Metal Pins

Hydraulic Disc

Shimano XTR M9120 Hydraulic Disc with 203 mm Front Rotor and 180 mm Rear Rotor, Shimano ICE-Technology Rotors (Carbon Steel Disc, Aluminum Alloy Core), Quad Piston Calipers with Heat Sinks, Shimano Two-Finger Levers with Free Stroke Adjust and Tool Free Adjustable Reach


More Details

Trail, Mountain

United States, Canada

2 Years Comprehensive, Lifetime Frame

3.2 lbs (1.45 kg)

4.2 lbs (1.9 kg) (2.88lb 1.31kg Bottom Bracket Transmission)

15.5 in (39.37 cm)16.5 in (41.91 cm)18.5 in (46.99 cm)20 in (50.8 cm)

16.5" Seat Tube, 23" Top Tube, 16" Reach, 28.5" Stand Over Height, 31.5" Minimum Saddle Height, 41" Maximum Saddle Height, 30" Width, 76.25" Length, 46.25" Wheelbase

Gloss Alpine Navy Smoke with Trek White and Black Accents, Three More Stock Colors, Optional Project One Custom Colors

Fox Factory Air Suspension Integrated Into Trek ISO Strut, 60mm Travel, Remote Lockout, Rebound Adjust Dial (1-12), 36mm Stanchion with Kashima Anodized Coating, Boost 148mm Hub Spacing, 12mm Thru-Axle with Quick Release

Bottle Cage Bosses on Downtube

Rubber Bumper on Downtube Protects Carbon Frame from Fork Oversteer if Knock Block Headset Chip Breaks, Long Rubberized Slap Guard on Top of Chainstay, Metal Bottom Bracket Chainline Protector, Optional Storage Bay Downtube Cover (Replaces Battery and Motor in Downtube, Weighs 1lb Total)

Locking Removable Downtube-Integrated Battery Pack and Motor with Shaft Drive Interface at Bottom Bracket, 1.4lb 36 Volt 2 Amp Charger with Magnetic Rosenberger Plug, Motor Cadence Support 55 to 125 RPM Motor Support, ABUS Locking Core (Keyed-Alike Code Card), Maximum Total Weight Limit 300 pounds (136 kg)


Battery Level (5 Dots), Assist Level (Green BreezeMode, Blue RiverMode, Pink RocketMode), Top LED Error Notice (Orange or Red)

Advanced Pedal Assist (Measures Rear Wheel Speed, Pedal Cadence, and Pedal Torque in Real Time, Green BreezeMode Consistent 100 Watts, Blue RiverMode Up to 300 Watts, Pink RocketMode Up to 450 Watts)

20 mph (32 kph)

Video Reviews

Written Reviews

This review was provided for free, but Trek Coquitlam supplied a temporary demo bike for me to test. My goal is to be transparent and unbiased with you, this video and writeup are not meant to be an endorsement of Trek products. I welcome your corrections, additions, and feedback in the comments below, and the Trek electric bike forums.


  • Trek is one of the “Big Three” North American bicycle manufacturers, along with Giant and Specialized. Trek launched in 1975, making hand-brazed steel frames. Since then, they have grown into a global powerhouse in the cycling industry with distributors in 90 different countries and hundreds of dealers that assemble and support the products.
  • The E-Caliber line consists of five models ranging from 9.6 (Shimano drivetrain, 18.49kg 40.75lb), 9.8 XT (Shimano drivetrain, 16.94kg 37.34lb), 9.8 GX (SRAM drivetrain, 16.99kg 37.45lb), 9.9 XTR (the feature of this review, 15.95kg 35.15lb), and 9.9 XX1 AXS (SRAM wireless shifting, 15.77kg 34.76lb). They are all built around the same carbon fiber frame with the single pivot IsoStrut rear suspension design… just using different drivetrains and alloy wheels vs. carbon. The motor and battery are the same. Compared to the non-electric Trek Supercaliber, the bike offers a longer reach and slacker head tube angle to improve control at sustained speed.
  • You might notice the Bontrager name on some of the components in this review. Bontrager is Trek’s in-house component brand, and is therefore common on many of Trek’s electric bicycles. Basically, Bontrager is the same company as Trek but they focus on accessories like rims, bars, posts, pedals, racks, bags, and lights.


  • Purpose built ebike frame sold in four sizes using ebike specific geometry based on the non-electric Trek Supercaliber. The frame and IsoStrut are made from OCLV Mountain Carbon described as mountain-specific carbon fiber engineered to withstand the extreme demands of off-road racing. Blends light weight, responsiveness, and just enough compliance in the seat stays to eliminate the need for a heavy rear pivot system. The IsoStrut uses a single pivot in front of the bottom bracket to improve pedaling efficiency (reduce bob) and a slide shock integrated into the top tube which is fully adjustable. The narrow seat stays are designed to flex as the rear triangle changes position, while the taller chain stays remain mostly fixed so the chain length does not change (which might otherwise produce kickback).
  • Beyond the frame and rear triangle, many other hardware parts have been upgraded to carbon to save further weight including the rims, crank arms, seat post, spacers, stem clamp arms, handlebar, and saddle rails. The stem clamp is Blendr compatible for attaching cycling computers and lights in a clean beautiful way using Trek / Bontrager accessories.
  • The bike uses lightweight air suspension from Fox front and rear, which are fully adjustable (air pressure for compression, dials for rebound, and remote trigger on left for dual lockout). The front travel is 120mm while the rear is just 60mm, this setup is optimized for reduced weight and control rather than the comfort of a trail bike that might encounter larger hits. For that sort of ebike, consider Trek’s Powerfly FS model (which is their entry point) or the longer travel Rail all-mountain build.
  • The bike may be ridden with or without the drivepack (motor and battery downtube insert) and is designed to freewheel as efficiently as a non-electric bike so there’s no additional pedal or coasting drag. The bike even includes an empty insert that replaces the drivepack for acoustic riding that can be used to store things like food, tools, and repair parts. This hollow cover weighs just under one pound (0.45kg) bringing the total non-electric weight of the bike to 30.1lbs (13.65kg). This is just ## heavier than the non-electric Trek Supercaliber which weighs 20.49lbs (9.29kg).
  • Wider Boost hub spacing front and rear improves the spoke bracing angle which adds strength and provides the stiffness of a smaller diameter wheels (such as 26″ or 27.5″), the benefit of taller 29″ wheels here is a lower attack angle to smooth out bumpy terrain and improve rolling momentum once rolling with high air volume for comfort and a narrower tire contact patch for nimble steering and reduced drag. You can run wider tires on this bike if you want, and use a larger chainring than the stock 32 tooth, without affecting the q-factor and pedaling efficiency.
  • Sturdy thru-axles front and rear, 15mm up front with an empty 6mm hex bolt and 12mm in the rear with a 6mm hex bolt that has a magnetic lever tool inserted (you can unscrew the front and rear bolts with this tool like a quick release system).
  • As one might expect with a more premium cross country build, Trek is using the latest standards such as a wider 35mm handlebar for improved stiffness and wider 31.6mm seat post which can be swapped for a dropper post… the bike even comes with an additional lever to attach at the remote dropout module near the left grip so the cockpit isn’t cluttered!
  • Minimalist display + control panel, fully integrated battery + motor, and internally routed cables make the bike very stealthy, it hardly looks or sounds electric. Note the Control Freak cable management that Trek designed to be easy to work with using a large grommet opening but also lightweight and quiet. It allows any combination of shift, brake, lockout, and dropper post lines to be routed through the frame for clean looks.
  • The Fazua Evation control pad uses touch sensitive up and down buttons to adjust assist… but for those who prefer physical or if the touch-sensitivity isn’t working well in rain, the center on/off button can double as a cycle to navigate through the levels of assist (off, green, blue, red).
  • The drive system supports a Bluetooth LE (Low Energy) connection to bicycle computers and a smartphone app called the Fazua Rider app (available in April 2021). This app provides GPS navigation, trip information, and feedback about motor power, remaining battery capacity, distance to empty, speedometer, cadence, rider power, rider torque, technical overview and battery charge information, support functions, and direct access to Fazua service, the ability to share rides with friends, and summaries and analysis of the data post ride. You will also be able to control some of the assist levels and power curves.
  • Since the bike geometry is setup for cross country riding, the head tube angle isn’t as slack and the crowns of the fork could collide into the downtube in the event of oversteer or a crash. Trek is using the Knock Block headset with a 62-degree limit so this doesn’t happen. Basically, you cannot steer past a certain point. If you really force it and the chip inside the Knock Block breaks, there is a rubberized bumper on the downtube that acts as a second layer of protection for the carbon frame.
  • Big upgrade from Fazua for their Evation drive unit with the Black Pepper software that increases power output to 300 watt to 450 watt peak and pedal cadence support to 55 to 125 RPM! I test rode this motor a year and a half ago on a BULLS ebike and it wasn’t nearly as satisfying as this. The peak torque output of 55 newton meters was very capable during my little climb tests.


  • The biggest gripe I have with this ebike is that the battery cannot be charged while mounted to the frame. You have to insert the key (on the non-drivetrain side of the bike) while balancing the bike (because it does not have a kickstand) and then remove the pack (which did tumble out onto my foot once during testing). Then, you connect it to the modest and lightweight 2 amp charger, which uses a magnetic Rosenberger interface. That’s a lot of steps and potential for the bike tipping or battery dropping EVERY TIME you need a recharge.
  • Unlike some of the competition, Specialized’s SL motor and battery setup, there is no easy way to increase the battery capacity of this ebike and take the battery along without using a backpack. Specialized designed a bottle shaped battery that can mount directly to the frame whereas the Fazua battery must be stored in a pack or their optional battery bag which hangs from the top tube… but may not fit as neatly on this full suspension frame setup.
  • There are no USB charging ports to tap into the ebike battery system if you decide to use the Fazua Rider smartphone app, but that’s not a huge deal considering that the battery capacity is fairly low at 252 watt hours. I was surprised that the app has some up-sell features that you have to pay for… that’s something I’ve never seen from another ebike company, and most of the readouts were provided free from systems like Bosch, Shimano, Yamaha, and Brose.
  • It appears that the bike does not have walk mode, which isn’t a big deal considering how lightweight the bike is, but this is a feature that most other ebikes do offer. It also does not appear to allow for integrated lights, you can get the individually powered rechargeable Bontrager lights from Trek instead.
  • I love the ABUS Plus Code keys, because you can order locks that have matching cylinders! The downside is that these can take quiet a while to order and receive in North America, from what I’ve heard at some shops. I also found that inserting and twisting the key required some patience and extra attention.

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