2024 Trek Rail 9.9 CXR Gen 4 Electric Mountain Bike

£12,950.00

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The 2024 Trek Rail 9.9 CXR Gen 4 Electric Mountain Bike is a race-ready long-travel e-bike that's ready to accelerate to the full right off the starting line. It features Trek's best carbon frame, smooth RockShox suspension and top-tier Shimano XTR drivetrain. But the real show stealer on this powerhouse is the limited-edition Bosch Performance Line CXR motor that accelerates faster and offers sustained power for ripping through rock gardens without pedalling. It's equipped 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.

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, ultra-responsive Shimano XTR 1x12 drivetrain and burly but light carbon wheels. 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.

This bike is perfect for

Mountain bikers who 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 customisation and want all of the cool features of Bosch's smart system.

Key Features
  • The 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
  • 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
  • The 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 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 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

Electric Bike Updates and Diagnostics

As electric bikes have become more sophisticated it’s important to stay on top of updates. Just like your home computer or smart phone regular updates are now released for most electric bike systems. If you buy a bike from Cycles UK we will do electric bike updates and diagnostics you need free of charge.

Electric Bike Updates

Electric bike updates can help to improve battery life, tweak how the motor works and fix bugs and problems. Most systems will require you to plug your bike into some specialist software at an authorised dealer. At Cycles UK we are authorised dealers for top electric bike brands including Specialized, Trek, Orbea, Whyte, Cannondale and Raleigh. As a result our stores have the software and hardware to run updates on all the major electric bike systems including Bosch, Shimano and Ebikemotion.

Free Electric Bike Updates and Diagnostics

We now provide free updates and diagnostics for life on any electric bike purchased from Cycles UK.

Electric Bike Motors Explained

Electric bikes have really come into their own in the last couple of years. Thanks to advances in electric bike motors and batteries. A couple of bike manufacturers, most notably Specialized, are making their own electric bike motors. The vast majority of bike companies are using the same motors. So, you will find exactly the same electric motor being used on bikes from different brands and at different price points. In this guide, we’ll take you through the main types of electric bike motors. Look at the differences between the most commonly used brands.

Electric Bike Hub Motors vs Mid-Drive Motors

Electric bikes tend to either come with a hub motor or a mid-drive motor. Mid-drive motors sit where the cranks and bottom bracket are on a bike and drive the cranks and chain around. Hub drive motors sit in the middle of the wheel and drive the wheel directly. Hub drive electric bikes are cheaper but less efficient, and less smooth, to ride.


Read our guide to electric bike motors

Trek Electric Bike Range Guide

The Trek electric bike range has been pretty enormous at times. This has mainly been due to a single model of bike being available in multiple battery and colour variations so you quickly ended up with dozens of variants. Thankfully Trek have scaled this back a little recently, and their electric bike range is now easier to understand.

Until recently nearly all Trek electric bikes came with Bosch motors. For the 2023 season they are continuing with Bosch but also introducing motors from new brands like TQ and Hydrive on selected models.

Read our full Trek electric bike range guide

Price Match at Cycles uk

We understand that price is important, so we regularly price-check our competitors to make sure we have the best offers available. We recognise that we will not always be the cheapest, so if you see the same product cheaper from any of our competitors then please get in touch via the form below and we will do our best to match any reasonable advertised price.

Trek made their first bikes in 1976 in a barn in Wisconsin. Now they’re one of the biggest bike brands in the world. Trek bikes cover everything from professional-level road and mountain bike race bikes to commuters, hybrids and kids bikes. There is a strong heritage of racing at Trek and many Trek bikes have a strong race influence. They take a very scientific approach to researching bike and human performance and then make the fastest and most efficient bikes they can.

It doesn’t stop their attention and passion for cycling flows through everything they do. Since the 1990s, Trek has supported Places for Bikes. Places for Bikes is an advocacy organisation in the USA that gets more people on bikes more often! Places for Bikes ethos falls in line with the companies mission statement to:

Build only products we love. Provide incredible hospitality to our customers, and change the world by getting more people on bikes.

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, 34.9 mm seat tube, magnesium rocker link, Motor Armour, Mino Link, ABP, Boost148, 12 mm thru-axle, 150 mm travel

Fork - RockShox ZEB Ultimate, AirWiz, DebonAir spring, Charger 3 RC2 damper, 1.8" oversized tapered steerer, eMTB optimised crown, 44 mm offset, Boost110, 15 mm Maxle Stealth, 160 mm travel

Shock - RockShox Super Deluxe Thru Shaft, AirWiz, 230 mm x 57.5 mm

Wheel front - Bontrager Line Pro 30, OCLV Mountain Carbon, Tubeless-Ready, 6-bolt, Boost110, 15 mm thru-axle

Wheel rear - Bontrager Line Pro 30, OCLV Mountain Carbon, Tubeless Ready, Rapid Drive 108, 6-bolt, Shimano MicroSpline freehub, Boost148, 12 mm thru axle

Skewer rear - Bontrager Switch thru-axle, removable lever

Tyre - Bontrager SE5 Team Issue, Tubeless Ready, Core Strength sidewalls, aramid bead, 120 tpi, 29x2.50". Bontrager SE6 Team Issue, Tubeless Ready, Core Strength sidewalls, aramid bead, 120 tpi, 29x2.50"

Tyre part - Bontrager TLR sealant, 180 ml/6 oz

Quarq TyreWiz tyre pressure monitors

Shifter - Shimano XTR M9100, 12-speed

Rear derailleur - Shimano XTR M9100, Shadow Plus, long cage, 51-T max cog

Crank - E*thirteen E*spec Race carbon, 165 mm length

Chainring - E*thirteen E*spec, 34T alloy, 55 mm chainline

Cassette - Shimano XTR M9101, 10-51, 12-speed

Chain - Shimano Dura-Ace/XTR M9100, 12-speed

Pedal - VP-536 nylon platform

Saddle - Bontrager Arvada, austenite rails, 138 mm width

Seatpost - Bontrager Line Elite Dropper

Handlebar - Bontrager Line Pro, OCLV Carbon, 35 mm, 27.5 mm rise, 780 mm width

Grips - Bontrager XR Trail Elite, nylon lock-on

Stem - Bontrager Line Pro, 35 mm, Knock Block, Blendr-compatible, 0-degree, 45 mm length

Brake - Shimano XTR M9120 4-piston hydraulic disc

Brake rotor - Shimano RT86, 6-bolt, 203 mm

Battery - Size: S Bosch PowerTube 625Wh, smart system. Size: M, L, XL Bosch PowerTube 750Wh, smart system

Charger - Bosch standard 4A, 230V, smart system

Controller - Bosch System Controller BRC3100, smart system

Motor - Bosch Performance Line CX Race Edition, smart system, magnesium motor body, 85 Nm, 20 mph or 32 km/h max assist (25 km/h max assist in EU and APAC)

Weight - Medium size - 23.05 kg / 50.82 lb

Weight limit - This bike has a maximum total weight limit (combined weight of bicycle, rider and cargo) of 136 kg (300 lb).

Colours DEEP SMOKE, LAVA
Sizes L, M, S, XL
Brand Trek
Model Year 2024
Barcodes 768682485569, 768682485644, 768682485668, 768682485705, 768682485781, 768682485866, 768682485989, 768682486047
SKUs / Part Numbers 5304841, 5304842, 5304843, 5304844, 5304845, 5304846, 5304847, 5304848

Please note: Manufacturers can sometimes change the specification of the products from time to time.

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