Trek Rail 9.9 XX1 AXS Gen 4 2023

The 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 customisation 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 750 Wh 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

The 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

1. The new System Controller shows your currently-selected assist level and remaining battery level. It’s neatly integrated into the top tube for maximum protection and a sleek look.
2. 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
3. TyreWiz and AirWiz let you confirm that your tyres, fork and shock are at the right pressure at a glance. No more getting the pump or gauge out just to check
4. Intelligent eMTB and eMTB Lite modes adjust the assist automatically based on your input to give you just the right amount of power for your ride
5. The new frame is extra stout with a 34.9 mm seat tube to accommodate more robust dropper posts and an oversized head tube that works with burly e-MTB-optimised forks for less flex and more precise steering

Geometry