Trek Rail 9.9 Gen 4
Rail 9.9 is our best long-travel electric mountain bike. You get an extra-beefy carbon frame, unbelievably smooth RockShox suspension, super-precise Shimano/SRAM drivetrains, and a powerful Bosch Performance Line CX motor with an extra-long range battery and smart system, plus the new Mini Remote and System Controller display that sits flush with the top tube and pairs with the eBike Flow app to give you activity tracking, navigation, and Bluetooth connectivity.
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.
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 1x12 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 super-refined shifting of XTR, 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
- 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
- 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
- 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