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Trek Rail 9.9 X0 AXS T-Type Gen 4

Trek Rail 9.9 X0 AXS T-Type Gen 4
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Rail 9.9 is our best long-travel electric mountain bike. You get an extra-beefy carbon frame, unbelievably smooth RockShox suspension, SRAM's best wireless electronic drivetrain, and a powerful Bosch smart system Performance Line CX motor with an extra-long range battery and the new Mini Remote. The new System Controller display sits almost flush with the top tube for a sleek look wherever you roll that stays out of the way when you're riding hard.

It's right for you if...
You want to spare no expense on your e-MTB experience. You want the most adjustability, smoothest performance, longest range, and most high-tech electric assist you can get. You love customization and want all the cool features of the Bosch smart system, and you want wireless electronic shifting.

The tech you get
An upgraded OCLV Mountain Carbon frame with longer reach and oversized head tube and seat tube for maximum strength. An extra-long-range 750Wh battery, ultra-adjustable RockShox ZEB Ultimate fork, RockShox Super Deluxe Ultimate Thru Shaft shock, and SRAM's wireless X0 AXS transmission. You get Bosch's smart system Performance Line CX with a new Mini Remote and Bluetooth® System Controller display that's integrated into the top tube, plus AirWiz pressure monitoring.

The final word
Rail 9.9 is all about top-shelf tech. The best enduro fork from RockShox, Bosch's biggest battery, the smooth shifting of X0 AXS, an updated frame, and AirWiz pressure monitoring, plus Bosch's latest tech with smart system.

Why you'll love it

- Carbon Rail Gen 4 has the same enduro-inspired geometry and huge battery as the previous generation, but now it has a pocket in the top tube that makes Gen 4 compatible with Bosch’s integrated System Controller and Mini Remote
- Its clean cockpit is minimalist and sleek, and smart system makes it easy to add a display if you want more data
- Intelligent eMTB and Tour+ modes automatically adjust the assist based on your input to give you just the right amount of power for your ride
- SRAM's direct-mount T-Type wireless transmission delivers next level performance with precise shifts under load and unmatched durability
- Trek's Removable Integrated Battery (RIB) system looks great and is super user-friendly: it fully hides the battery in the frame for protection, makes it easy remove the battery without tools, and lets you mount a water bottle cage


Removable Integrated Battery
RIB is a one-piece battery and cover with a built-in handle that can easily be removed and re-installed in the frame with no tools and no hassle. It’s the most convenient way to remove your battery for transport, security, or just easier charging.

Bosch Performance Line CX motor
Bosch Performance Line CX sets the standard for eMTB performance with up to 85Nm of torque and an intelligent eMTB mode with Extended Boost that automatically adjusts the amount of assist based on the terrain.

Bosch Mini Remote
The compact, ergonomic Mini Remote lets you easily change assist level, activate Walk mode, or turn on optional lights, all without moving your hand off the handlebar. Plus, it's wireless and connects with your System Controller via Bluetooth

Transition to transmission
SRAM Eagle T-Type transmission mounts directly to the frame, skipping that pesky derailleur hanger of yesteryear. This makes for a more robust system that's not only cleaner looking, it's also more precise under load, and easier to set up.

Bosch System Controller
The System Controller gives you a quick overview of your assist mode and battery level without distracting you from the ride. It's integrated into the top tube so it's out of the way but still easy to see with LED indicators. It also connects to the eBike Flow app via Bluetooth for accessing ride stats and performing system updates.

RockShox AirWiz and Quarq TireWiz
TyreWiz monitors your tire pressure while AirWiz monitors your fork and shock pressure. Set your desired pressure in the SRAM AXS app and then just check the lights before each ride—red means you need a pump, green means go ride.

Bosch eBike Flow app
The new eBike Flow app turns your ride into a personalized experience. Use it to customize your motor's assist behavior, track your ride stats, and integrate your data with apps like Strava and Apple Health. There's even handy features like navigation and service reminders.


Frame size number15.5"15.5"17.5"17.5"19.5"19.5"21.5"21.5"
Frame size letter Small Small Medium Medium Large Large X-Large X-Large
Geometry position High Low High Low High Low High Low
Wheel size 29" 29" 29" 29" 29" 29" 29" 29"
A — Seat tube 41 41 42 42 45 45 50 50
B — Seat tube angle 71.2° 70.8° 71.2° 70.8° 71.2° 70.8° 71.2° 70.8°
Effective seat tube angle 77.1° 76.7° 77.1° 76.7° 77.1° 76.7° 77.1° 76.7°
C — Head tube length 10.5 10.5 11 11 12.5 12.5 14 14
D — Head angle 64.6° 64.2° 64.6° 64.2° 64.6° 64.2° 64.6° 64.2°
E — Effective top tube 57.9 58 60 60.1 63.8 63.9 67.1 67.3
F — Bottom bracket height 34.6 34.1 34.6 34.1 34.6 34.1 34.6 34.1
G — Bottom bracket drop 2.7 3.3 2.7 3.3 2.7 3.3 2.7 3.3
H — Chainstay length 44.7 44.8 44.7 44.8 44.7 44.8 44.7 44.8
I — Offset 4.3 4.3 4.3 4.3 4.3 4.3 4.3 4.3
J — Trail 13 13.3 13 13.3 13 13.3 13 13.3
K — Wheelbase 121.3 121.4 123.6 123.6 127.7 127.8 131.3 131.4
L — Standover 76.1 75.6 77.3 76.8 77 76.5 76.8 76.3
M — Frame reach 43.6 43.2 45.6 45.2 49.1 48.7 52.1 51.7
N — Frame stack 62.5 62.8 62.9 63.3 64.3 64.6 65.6 66
SizeRider HeightInseam
Small 155 - 165 cm 74 - 78 cm
5'1" - 5'5" 29" - 31"
Medium 165 - 176 cm 79 - 83 cm
5'5" - 5'9" 31" - 33"
Large 177 - 188 cm 84 - 89 cm
5'10" - 6'2" 33" - 35"
X-Large 188 - 195 cm 89 - 91 cm
6'2" - 6'5" 35" - 36"


Frame OCLV Mountain Carbon main frame, 1.8'' lower head tube, Bosch System Controller compatible, Removable Integrated Battery (RIB), Knock Block 2.0, guided internal routing, 34.9mm seat tube, magnesium rocker link, Motor Armor, Mino Link, ABP, Boost148, 12mm thru axle, 150mm travel
Fork RockShox ZEB Ultimate, AirWiz, DebonAir spring, Charger 3 RC2 damper, 1.8'' oversized tapered steerer, eMTB optimized crown, 44mm offset, Boost110, 15mm Maxle Stealth, 160mm travel
Rear Shock RockShox Super Deluxe Thru Shaft, AirWiz, 230mm x 57.5mm
Wheels Front: Bontrager Line Pro 30, OCLV Mountain Carbon, Tubeless Ready, 6-bolt, Boost110, 15mm thru axle
Bontrager Line Pro 30, OCLV Mountain Carbon, Tubeless Ready, Rapid Drive 108, 6-bolt, SRAM XD driver, Boost148, 12mm thru axle
Tires Size: S, M, L, XL Bontrager SE5 Team Issue, Tubeless Ready, Core Strength sidewalls, aramid bead, 120 tpi, 29x2.50''
Size: S, M, L, XL Bontrager SE6 Team Issue, Tubeless Ready, Core Strength sidewalls, aramid bead, 120 tpi, 29x2.50''
Crankset SRAM X0 Eagle, 34T, T-Type,160mm length
Shifters SRAM AXS POD Ultimate
Rear Derailleur SRAM X0 Eagle AXS, T-Type
Cassette/Freewheel SRAM Eagle XS-1295, T-Type, 10-52, 12 speed
Chain SRAM X0 Eagle, T-Type, 12 speed
Brakes SRAM Code Silver 4-piston hydraulic disc
Tape/Grips Bontrager XR Trail Elite, nylon lock-on
Stem Bontrager RSL Integrated handlebar/stem, OCLV Carbon, 27.5mm handlebar rise, 820mm width, 0 degree stem rise, 45mm stem length
Seatpost Size: S RockShox Reverb AXS, 100mm travel, wireless, 34.9mm, 340mm length, Size: M RockShox Reverb AXS, 150mm travel, wireless, 34.9mm, 440mm length, Size: L, XL RockShox Reverb AXS, 170mm travel, wireless, 34.9mm, 480mm length
Saddle Bontrager Arvada, austenite rails, 138mm width
Pedals VP-536 nylon platform
Motor Bosch Performance Line CX, smart system, magnesium motor body, 85 Nm
Battery Size: S Bosch PowerTube 625Wh, smart system
Size: S, M, L, XL SRAM eTap battery pack (with charger)
Size: M, L, XL Bosch PowerTube 750Wh, smart system
Controller/Display Size: S, M, L, XL Bosch System Controller BRC3100, smart system, Size: S, M, L, XL Bosch Mini Remote BRC3300, smart system, 22.2mm
Charger Bosch standard 4A, 110V, smart system

* Subject to change without notice.