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  • Rail 9.9 CX Race Gen 4
  • Rail 9.9 CX Race Gen 4
Overview

It's right for you if...

You want seriously fast acceleration and the best long-travel e-MTB you can find. Components matter to you, and you want the most adjustability, smoothest performance, longest range, and most high-tech assist you can get. You love customization and want all of the cool features of Bosch's smart system.

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 ultra-responsive Shimano XTR 1x12 drivetrain. Bosch's new limited-edition Performance Line CXR motor with faster acceleration and extended boost, a new Mini Remote, and Bluetooth® System Controller display that's integrated into the top tube.

The final word

Rail 9.9 CXR is all about power. It combines top-shelf tech with Bosch's ultra-fast accelerating, limited-edition, Performance Line CXR motor for cruising out of corners at top speed, and their biggest battery possible to power you, lap after lap. RockShox's best enduro fork, the super-refined shifting of XTR, an updated frame, and AirWiz pressure monitoring come together to make it the full package for e-MTB racing.

favorite_borderWhy you'll love it

  1. Bosch's limited-edition CXR motor gives you more power out of the gate and keeps it sustained for ripping through rock gardens when you can't pedal
  2. 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
  3. 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
  4. 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
  5. 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

More options

NEW 2023

Rail 9.9 XX1 AXS Gen 4

$13,799.99 - $13,999.99 

NEW 2023

Rail 9.9 XTR Gen 4

$12,549.99 - $12,749.99 

NEW 2023

Rail 9.8 GX AXS Gen 4

$10,299.99 - $10,499.99 

NEW 2023

Rail 9.8 XT Gen 4

$8,999.99 - $9,199.99 

NEW 2023

Rail 9.7 Gen 4

$7,549.99 - $7,749.99 

NEW 2023

Rail 7 Gen 3

$6,649.99 

NEW 2023

Rail 5 Gen 3

$5,649.99 

SALE 2023

Rail 9.9 XX1 AXS Gen 3

$13,499.99  | $13,799.99 

SALE 2023

Rail 9.9 XTR Gen 3

$12,249.99  | $12,549.99 

SALE 2023

Rail 9.8 GX AXS Gen 3

$9,999.99  | $10,299.99 

SALE 2023

Rail 9.8 XT Gen 3

$8,699.99  | $9,199.99 

SALE 2023

Rail 9.8 GX Gen 3

$8,699.99  | $9,199.99 

SALE 2023

Rail 9.7 Gen 2

$7,049.99  | $7,549.99 

SALE 2023

Rail 7 Gen 2

$5,999.99  | $6,649.99 

SALE 2023

Rail 5 Gen 2

$4,999.99  | $5,649.99 

Which generation is right for you? 

Go Rail Gen 4 for minimalist smart system compatibility, Gen 3 for smart system with visible control at the bars, or Gen 2 for a legacy Bosch system that saves your wallet.

Learn more

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Features

Performance Line CX Race motor

The limited-edition Race motor delivers explosive acceleration, full throttle jump out of corners, and the fastest possible ride. The Performance Line CX Race Edition is the perfect choice for e-MTB racers and expert riders who want more power off of the starting line.

Learn more

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.

Watch video

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

Learn more

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.

Learn more

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.

Read more

Shimano XTR

Designed to meet the highest level of competitive mountain bike racing needs, with second to none performance and experience, Shimano XTR M9100 brings lightweight, high-end versatility to XC, enduro, and marathon racing.

Suspension Calculator

This suspension calculator will help you optimize your suspension settings for your riding weight. Simply follow the steps to find your best set up.

Learn more

Complete Tubeless System

Tubeless Ready rims and tires make it easy to ditch the tubes so you get better traction, fewer flats, and less weight. You're ready to roll right out of the box with the included TLR rim strips, valves, and sealant.

Learn more

Carbon Care Wheel Loyalty Program

Every set of Bontrager carbon wheels is backed by the Carbon Care Wheel Loyalty Program. In the unlikely event that you damage your Bontrager carbon wheels within the first two years of ownership, we’ll repair or replace them for free.

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Bosch PowerTube 750

Bosch's biggest battery for your biggest rides. PowerTube 750 delivers 20% more range and a long service life.

Integrated speed sensor

You've got one less detail to sweat with the integrated speed sensor. The chainstay-mounted sensor stays protected while the custom hub-mounted magnet stays secure—no more error codes from mis-aligned sensors.

Oversized 34.9mm dropper post

Bigger is better. The oversized seat tube diameter gives more support and strength for longer travel droppers, and allows for more robust, durable internals that work faster.

Mino Link adjustable geometry

Fine tune head tube angle by 1/2° and BB height by up to 10mm with the simple turn of a nut. Just flip the link to choose between slack or slacker geometry, without negatively affecting suspension performance. A Trek exclusive.

Learn more

Specs Sizing
Geometry Service Reviews
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