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Trek Rail 9.9 XX1 AXS Gen 4

Trek Rail 9.9 XX1 AXS Gen 4
  • Color: Deep Smoke
Deep Smoke
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This item can be purchased online and picked up at your convenience at our store. It is not able to be shipped.


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 XX1 AXS drivetrain. 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. RockShox's best enduro fork, Bosch's biggest battery, the smooth shifting of XX1 AXS, an updated frame, and AirWiz pressure monitoring, plus Bosch's latest tech with smart system.

Why you'll love it
- The new System Controller shows your currently-selected assist level and remaining battery level. Its neatly integrated into the top tube for maximum protection and a sleek look.
- Bosch's new smart system gives you all the same power and responsiveness with a new discrete Mini Remote that's streamlined with just the controls you need at your fingertips to toggle through assist levels or change to walk mode
- TyreWiz and AirWiz let you confirm your tires, fork, and shock are at the right pressure at a glance. No more getting the pump or gauge out just to check
- Intelligent eMTB and eMTB Lite modes automatically adjust the assist based on your input to give you just the right amount of power for your ride
- The new frame is extra stout with a 34.9mm seat tube to accommodate more robust dropper posts, and an oversized head tube that works with burly e-MTB-optimized forks for less flex and more precise steering


All measurements provided in cm unless otherwise noted.
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
5'1" - 5'5"
74 - 78 cm
29" - 31"
Medium 165 - 176 cm
5'5" - 5'9"
79 - 83 cm
31" - 33"
Large 177 - 188 cm
5'10" - 6'2"
84 - 89 cm
33" - 35"
X-Large 188 - 195 cm
6'2" - 6'5"
89 - 91 cm
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 Ultimate RT, 230mm x 57.5mm
Wheels Front: Bontrager Line Pro 30, OCLV Mountain Carbon, Tubeless Ready, 6-bolt, Boost110, 15mm thru axle
Rear: Bontrager Line Pro 30, OCLV Mountain Carbon, Tubeless Ready, Rapid Drive 108, 6-bolt, SRAM XD driver, Boost148, 12mm thru axle
Rims Bontrager Line Pro 30, OCLV Mountain Carbon, Tubeless Ready
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 E*thirteen E*spec Race carbon, 34T, 165mm length
Chainrings SRAM X-SYNC 2, 34T, alloy
Shifters SRAM Eagle AXS, wireless, 12 speed
Rear Derailleur SRAM XX1 Eagle AXS
Cassette/Freewheel SRAM Eagle XG-1299, 10-52, 12 speed
Chain SRAM XX1 Eagle, 12 speed
Brakes SRAM Code RSC 4-piston hydraulic disc
Rotors Size: S, M, L, XL SRAM 6-bolt, 200mm
Size: S, M, L, XL SRAM HS2, 6-bolt, 220mm
Handlebars Bontrager Line Pro, OCLV Carbon, 35mm, 27.5mm rise, 780mm width
Tape/Grips Bontrager XR Trail Elite, nylon lock-on
Stem Bontrager Line Pro, 35mm, Knock Block, Blendr compatible, 0 degree, 45mm 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 Wellgo VPE-536
Motor Bosch Performance Line CX, smart system, magnesium motor body, 85 Nm, 20 mph or 32 km/h max assist (25 km/h max assist in EU and APAC)
Battery Size: S Bosch PowerTube 625Wh, smart system
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, SRAM AXS aux power cable
Charger Bosch standard 4A, 110V, smart system

* Subject to change without notice.

Part Numbers

Option UPC MPN Store SKU
Deep Smoke / Medium 768682704349 5285864 RAI28343464
Deep Smoke / Large 768682704264 5285865 RAI284334364