Table of Contents

Trek Rail 9.9 XX1 AXS Gen 3 Review (2023)

Rail 9.9 XX1 AXS Gen 3 review

Table of Contents

Trek’s Rail range is the company’s series of bikes with the longest amount of travel, as well as also being the most versatile.


They were produced to take on the gnarly downhill routes, take a beating and come out the other side purring, ready for some climbing and technical twisty trails.


It’s a very competitive area of the e-MTB manufacturing world, because let’s face it, who doesn’t want to create and ride the complete package?


The second-highest spec bike in the Rail range is the Rail 9.9 XX1 AXS Gen 3, but it doesn’t come cheap.


There are a lot of other companies vying to snag customers in this sector, so is it worth taking the plunge on the Trek? Or are there better value for money bikes out there?


We’ve given the bike a thrashing to get the answers to your questions.


So, join us as we get stuck into the Rail 9.9 XX1 AXS Gen 3!

Our Verdict


This bike is so-nearly complete perfection.


It’s fitted with the best motor out their on the market, an enormous battery and is dripping in other high spec features – from the brakes, to the wheels, to the drivetrain and everything in between.


It will take you on rides which last all day long, and managed to retain a natural ride feel. It has many advanced and customisable features to nail your ride experience, and give you that truly bespoke feel with the bike.


It has one or two niggles, with a rattly battery being perhaps the main one, but Trek should be able to resolve that with a few tweaks. The price is eyewatering, too, but honestly, we can see why it costs as much as it does.


It’s a real beauty of a bike.



Trek Rail 9.9 XX1 AXS Gen 3

Rail 9.9 XX1 AXS Gen 3

Price: $13,499.99


The Rail 9.9 XX1 AXS Gen 3 has a robust OCLV carbon frame; one that’s designed to take on a lot of pressure from the big impacts. The bike isn’t the lightest, with a total weight of 22.54kg, but it does provide a really sturdy base to take on a lot of punishment.


It comes with a longer reach than previous incarnations and larger headtube and seat tube, to give the bike maximum strength and to help the rider feel cemented to the bike. The bike also has very low centre of gravity, which helps again with feeling tight to the trail and giving you that planted feeling.


One huge plus with this bike is the number of adjustable elements, which allow you to really nail your positioning. You can change up your geometry at pace through its Mino Link feature, allowing you to adjust your setup to the needs of the trail.


It means that if you ride on various types of terrain on the same day, you can switch up quickly and get into a better position to take on a steep descent or big climb.


The Rail 9.9 XX1 AXS Gen 3 comes with a monster Bosch PowerTube 750Wh battery. That’s a serious piece of kit to give you heck of a lot of range and will help keep you going all day long. Despite the chunky battery, the bike’s overall weight remains respectable, which is some achievement by the folk at Trek.


So, you might not have any concerns about the range of the battery, but unfortunately, we certainly had concerns about the noises coming from the battery. We found the battery rattled about quite a bit in the frame, which is a big worry given how much you can fork out for this bike. It seems like the connections aren’t that stable, which is very disconcerting.


We’re very impressed with the bike’s range, though; we never ran out of juice and did some all-day missions on this beast. Tighten up those connections and we might just have the perfect e-MTB battery.

Rail 9.9 XX1 AXS Gen 3 battery


The Rail 9.9 XX1 AXS Gen 3 is fitted with the punchy Bosch Performance Line CX, smart system motor. It’s another heavy-duty piece of electrical assistance, kicking out 85Nm of torque.


Between the battery and the motor it’s a really very good electrical set-up; in fact, we think the Bosch Performance Line CX is the best high performance e-MTB motor on the market at the moment.


It is a complete monster, which will help boost you up any climb you put in its way. Although providing a chunky boost, it doesn’t feel overly jerky or unnatural, it works in harmony with your pedal strokes and dies off when you ease off. It’s exactly what you want from an e-MTB motor.

Rail 9.9 XX1 AXS Gen 3 motor



There are various settings with the motor, some which are more suited to a lighter rider (less of a punch) and others more suited to a heavier rider (with more punch). The Tour+ function is perfect for a lighter rider, otherwise they may feel dragged about a bit by the huge amount of power the motor has.

There is a lot to admire about the motor, but it does make a bit of noise. This is a very minor criticism, though.

Motor Display

The Rail 9.9 XX1 AXS Gen 3 comes with an easy-to-use LED controller, to switch between the motor’s modes of assist, but it’s not in an ideal place.


For us it sits up a little too pronounced above the handlebars, which really does set it up for problems in the event of a crash or big impact. The Bosch Kiox 300, however, is a really nifty piece of kit and isn’t in the danger zone.


That’s hidden away nicely, but offers all sorts of options to choose from to really nail your ride performance. The amount of battery you have left is displayed as a percentage, which is spot on for us.


But you can also get trip distance info, current speed info, riding time data, your power output in watts, the range estimate you have left, cadence and much more. It’s a beauty of a device and fitting for that top notch motor.

Rail 9.9 XX1 AXS Gen 3 motor display


Rail 9.9 XX1 AXS Gen 3 shock
Rail 9.9 XX1 AXS Gen 3 front fork

The Rail 9.9 XX1 AXS Gen 3 comes with 160mm travel at the front and 150mm travel at the rear. The bike comes with RockShox ZEB Ultimate, AirWiz, DebonAir spring forks and RockShox Super Deluxe Thru Shaft, Air Wiz, rear shocks.


It’s an advanced suspension, and one which you can make plenty of adjustments to, to really get it spot on and ensure that you feel super comfortable on the trail. When you’re out riding on the trails, the suspension really purrs – it just feels unbelievably well-balanced and it feels at ease, even in some really bouncy territory.


You can put this Trek 9.9 through a heck of a lot, and you will still come out the other side with a smile on your face. Despite having less travel than some burlier bikes, we never encountered bottoming out, which is a real achievement from Trek.


It handles beautifully and the suspension certainly contributes to that.


Rail 9.9 XX1 AXS Gen 3 wheel
Rail 9.9 XX1 AXS Gen 3 tyres

The Rail 9.9 XX1 AXS Gen 3 has 29in wheels at both the front and the rear. A double 29in setup doesn’t always lend itself to being the most supple, handling-wise, but the other excellent features on the bike means it actually really does handle nicely.


The bike comes with Bontrager Line Pro 30, OCLV Mountain Carbon wheels. These are lightweight but incredibly sturdy. They can take a real beating out on the trail and give you good surface area on the ground, so you can really push the bike to its limits in the corners.


They’re complemented by the Bontrager SE6 Team Issue tyres, too, which have girthy teeth, and provide tonnes of traction. You can push this bike hard and both the tyres and wheels deliver.


With all that flying about on the trails you need a good solid pair of brakes and the Rail 9.9XX1 AXS Gen 3 comes with SRAM Code RSC hydraulic disc brakes, which do exactly what you need.


These are a seriously high-spec pair of brakes and they provide the bite you need to stop dead when called upon. This Trek 9.9 bike is well-balanced and the brakes are another feature which give you the confidence to ride hard and pull up when needed.

Rail 9.9 XX1 AXS Gen 3 brakes


Rail 9.9 XX1 AXS Gen 3 drivetrain

The Rail 9.9 XX1 AXS Gen 3 comes with an SRAM Eagle XG-1299, 12 speed cassette and SRAM XX1 Eagle AXS rear derailleur. Another high-spec setup, which delivers everything you want for the rest of this high-spec bike.


They take a hammering with the fast speeds you’re doing on this e-MTB, but are durable and can take it admirably.

Price: $13,499.99

What can we say, it’s clearly a lot of money, but we don’t think Trek has held back in any area here. The whole bike is fitted with high-spec bells and whistles; you get fantastic electrical components, suspension, frame, wheels, brakes, drivetrain and everything in between.


It’s a dream of a bike, but that doesn’t come cheap.

Trek Rail 9.9 XX1 AXS Gen 3 Facts & Figures

Size Configurations

S153 – 167 cm
5'0″ – 5'6″
72 – 79 cm
28″ – 31″
M161 – 175 cm
5'3″ – 5'9″
76 – 82 cm
30″ – 32″
L174 – 188 cm
5'9″ – 6'2″
82 – 88 cm
32″ – 35″
XL186 – 196 cm
6'1″ – 6'5″
87 – 92 cm
34″ – 36″
Frame size letterMMLLXLXL
Geometry positionLowHighLowHighLowHigh
Wheel size29″29″29″29″29″29″
Seat tube424245455050
Seat tube angle70.8°71.2°70.8°71.2°70.8°71.2°
Effective seat tube angle76.7°77.1°76.7°77.1°76.7°77.1°
Head tube length111112.512.51414
Head angle64.2°64.6°64.2°64.6°64.2°64.6°
Effective top tube60.16063.963.867.367.1
Bottom bracket height34.134.634.134.634.134.6
Bottom bracket drop3.
Chainstay length44.844.744.844.744.844.7
Frame reach45.245.648.749.151.752.1
Frame stack63.362.964.664.36665

Full Specs

FrameNEW OCLV Mountain Carbon main frame, 1.8″ lower head tube, 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
ForkRockShox ZEB Ultimate, AirWiz, DebonAir spring, Charger 2.1 RC2 damper, e-MTB optimised crown, tapered steerer, 44 mm offset, Boost110, 15 mm Maxle Stealth, 160 mm travel
ShockRockShox Super Deluxe Thru Shaft, AirWiz, 230 mm x 57.5 mm
Wheel frontBontrager Line Pro 30, OCLV Mountain Carbon, Tubeless-Ready, 6-bolt, Boost110, 15 mm thru-axle
Wheel rearBontrager Line Pro 30, OCLV Mountain Carbon, Tubeless Ready, Rapid Drive 108, 6-bolt, SRAM XD driver, Boost148, 12 mm thru-axle
Skewer rearBontrager Switch thru axle, removable lever
*TyreSize: M, L, XL
Bontrager SE5 Team Issue, Tubeless Ready, Core Strength sidewalls, aramid bead, 120 tpi, 29×2.50″
Size: M, L, XL
Bontrager SE6 Team Issue, Tubeless Ready, Core Strength sidewalls, aramid bead, 120 tpi, 29×2.50″
*Tyre partSize: M, L, XL
Bontrager TLR sealant, 180 ml/6 oz
Size: M, L, XL
Quarq TyreWiz tyre pressure monitors
Max tyre sizeFrame: 29×2.60″ Fork: See manufacturer
ShifterSRAM Eagle AXS, wireless, 12 speed
Rear derailleurSRAM XX1 Eagle AXS
Crank armE*thirteen E*spec Race carbon, 34T, 165 mm length
ChainringSRAM X-SYNC 2, 34T, alloy
CassetteSRAM Eagle XG-1299, 10-52, 12-speed
ChainSRAM XX1 Eagle, 12-speed
PedalVP-536 nylon platform
Max. chainring size34T
SaddleBontrager Arvada, austenite rails, 138 mm width
*SeatpostSize: M
RockShox Reverb AXS, 150 mm travel, wireless, 34.9 mm, 440 mm length
Size: L, XL
RockShox Reverb AXS, 170 mm travel, wireless, 34.9 mm, 480 mm length
Handlebar/stem (integrated)Bontrager Line Pro, OCLV Carbon, 35 mm, 27.5 mm rise, 780 mm width
GripsBontrager XR Trail Elite, nylon lock-on
StemBontrager Line Pro, 35 mm, Knock Block, Blendr-compatible, 0-degree, 45 mm length
HeadsetKnock Block Integrated, 58-degree radius, cartridge bearing, 1-1/8” top, 1.8” bottom
BrakeSRAM Code RSC hydraulic disc
*Brake rotorSize: M, L, XL
SRAM CenterLine, 6-bolt, round-edge, 180mm
Size: M, L, XL
SRAM CenterLine, 6-bolt, round edge, 200 mm
*BatterySize: M, L, XL
Bosch PowerTube 750Wh, smart system
Size: M, L, XL
SRAM eTap battery pack (with charger)
ChargerBosch standard 4A, 230V, smart system
MotorBosch Performance Line CX, smart system, magnesium motor body, 85 Nm
ComputerBosch Kiox 300, smart system
WeightM – 22.54 kg/49.7 lb (with TLR sealant, no tubes)
Weight limitThis bike has a maximum total weight limit (combined weight of bicycle, rider and cargo) of 136 kg (300 lb).

*Please note – spec applies to all sizes unless listed separately

How Does it Compare?

There’s a heck of a lot we admire on the Rail 9.9 XX1 AXS Gen 3, so it’s going to be a tough slice of competition to beat it. So, let’s have a gander at what else you could go for.

Norco Sight VLT C1

The Norco Sight VLT C1 is another one to keep an eye on.


It comes in at $10,000 – a heck of a lot cheaper than our Rail 9.9 XX1 AXS Gen 3, and despite that, the Norco Sight offers an appealing battery setup. You can choose between a 900Wh, 720Wh or a 540Wh battery, which is a great amount of choice to have at your disposal.


Unfortunately, it comes with the Shimano Steps EP8 motor, which we think is inferior to the Bosch on the Trek – particularly in terms of ride quality, natural power delivery, and motor display.


The Norco comes with a solid SRAM Code RSC brakes setup and the same SRAM drivetrain as our Trek – so no real difference there compared to the Trek Rail 9.9 we just reviewed. You also get 160mm travel at the front and 150mm travel at the rear, with Fox Factory Float 36 forks and Fox Factory Float X2 rear shocks – a solid pairing, too.


It’s a beauty to ride and can take a real hammering on the trails – it thrives when moving at real pace in a straight line or down a wild descent. It struggles a little more on the twisty sections, though, and doesn’t have the same adjustable options that the Trek has.


Although it costs a lot more, go for the Rail 9.9 XX1 GXS Gen 3.

Final Thoughts

What a bike the Trek Rail 9.9 AXS Gen 3 is. It’s a beauty in so many departments, and honestly, we think it’s so close to being perfection. This Trek Rail 9.9 has a chunky battery, which will last on almost any given ride you throw at it.


It’s fitted with the best Bosch motor out on the market, which will get you up some of the toughest climbs going and it has the display of dreams. The suspension is incredibly advanced and customisable, as is the geometry, so it handles a dream, is versatile and also has a brake, wheel and drivetrain setup capable of taking on anything.


We’re frustrated that Trek didn’t complete the perfect job by making sure that the battery doesn’t rattle about – it’s a real pain and could cause lasting damage to the battery, which could be an expensive fix. The price is also very high, but we know why – you’re getting some of the best components out there.


All in all, we love this one, now get stuck into the bike yourselves.

“If you enjoyed this review then make sure to check out our reviews of other Trek e-MTBs, including the Fuel EXe 9.8 GX AXS, Fuel EXe 9.9 XTR, Fuel EXe 9.8 XT, Fuel EXe 9.7 and Fuel EXe 9.5.