27.5 inch womens mountain bike rockrider st 120 - navy


This 27.5" mountain bike is designed for getting started with MTB touring in dry weather, for rides up to 1.5 hours.

An efficient, easy-to-handle MTB! Riding the ST 120 MTB you will feel the precision and light weight provided by the single chainring (1x9 speeds) and mechanical disc brakes. Change speeds easily!

Color: Navy blue
Size: size guide


Product benefits

Cycling comfort

Enjoy touring: raised position, 80 mm suspension, hammock saddle, FLEX seat post

Directional control

Control your trajectory: cable disc brakes, tyres with side knobs


Pedal efficiently: light aluminium frame, 9 speeds and fast tyres.

Ease of use

Adjust your speed without thinking: 9-speed single-chainring drivetrain.


An ultra-strong MTB: welded saddle, double-wall rims.

Lifetime warranty

ROCKRIDER offers a lifetime warranty on the frame, handlebar and stem.

Technical information

Which is the right size?

Several sizes available:
S: between 1.50m and 1.64m
M: between 1.65 m and 1.74 m
L: between 1.75 m and 1.84 m
XL: between 1.85m and 2.00m
To adapt the MTB to your height and size, try these tips:
1/ Sitting on the saddle, you should be able to touch the ground with the tips of your toes.
2/ To adjust the saddle height, your knee should be slightly flexed with the foot on the pedal in the lowest position.
3/ If you're between two sizes, choose the larger size.


A top tube with a relatively pronounced slope, over a wide range of sizes (S: 1.50m to XL: 2.00m),

The ST 120 mountain bike has a UNISEX frame.

As a WOMAN, if you choose the MEN'S model, we recommend at least purchasing the WOMEN'S SPORT 500 saddle which is fitted to the female form.


Our team of mountain bike enthusiasts created this ST 120 mountain bike at our B'Twin Village in Lille, France.

Recreational mountain bikers told us they wanted comfort, effectiveness and durability. Based on that, we designed and tested the ST 120 mountain bike, involving MTB riders at every stage.


Our designers created a frame that's easy to get onto.
The 100% aluminium CGF frame (Comfort Geometry Frame) is both comfortable and easy to handle. The slope angle has been designed to keep your back straight, while the rear bases were shortened to make the bike very agile in turns.

Front suspension

The 80 mm front suspension helps you get started with overcoming obstacles on slightly uneven trails easily.

Easily adjust the hardness using U-Fit technology (weight adjuster). Simply set the number to your weight (55 kg to 105 kg) using the dial on the fork.


This mountain bike has no rear suspension.

It is a "semi-stiff" mountain bike: perfect for beginners launching themselves into their first mountain bike touring rides. Compared to a full suspension mountain bike (with rear suspension), the advantages are clear: this mountain bike is lighter; you spend less energy on flat ground.


The single chainring is easy and efficient to use:
1 chainring and 9 speeds.
Accelerate on the flats and easily tackle the climbs.
With a single lever on the handlebar, you can change gears while hardly thinking!

-ROCKRIDER FC ATB 100 - 32-tooth single chainring equipped with 2 chain guides (anti-derailment)
-MICROSHIFT RD-M46-L rear derailleur
-MICROSHIFT SL-759 right shifter
-MICROSHIFT H092 9-cog cassette (11-36 teeth)
-Wide, sturdy KMC Z9 chain


With a stem that tilts 10° upwards, the riding position of the ST 120 is raised, accessible, and comfortable. In detail:
- 90mm aluminium stem with an angle of 10° for maximum comfort
- 640mm wide steel handlebar for stability and control
- "Soft touch" lamellar grips for a firm yet soft and pleasant grasp.


The saddle of the ST 120 is welded to prevent any movement of the saddle.

And because your comfort is our priority after your safety, we've added an exclusive wider Ergofit saddle with a hammock shape.

Easily adjust the height of your saddle with the Flex steel seat post (350mm or 400mm long depending on the bike size). Its smaller 27.2mm diameter provides your seat with natural flexibility, 30% more than a standard solution.


The Tektro TKD 68 160 mm double disc brakes provide powerful, progressive braking at the front and rear. The aluminium Tektro brake levers are precise, and easy to hold.
The brakes can be applied using only two fingers.
3 or 4 sets of 10 dry, intermittent stops are enough to break in your pads.
We recommend that you have your brakes checked at least once a year.


The 27.5" wheels of the ST 120 are tolerant and sturdy, with 19 mm double-walled rims with 28 spokes.
Start overcoming obstacles fearlessly, including small rocks, cracks, holes and bumps!
Because your first rides will be on dry ground, the Dry 27.5 x 2.0 tyres are most suitable. Their performance is optimised thanks to the rounded central section, whilst the side lugs provide good grip on turns.

Platform pedals

The Rockrider ST 120 mountain bike comes with resin mountain bike platform pedals for lower weight and increased safety.

If your foot slides on the pedal, there's less risk of injury.


We added a quick release system for easily removing/reattaching the front wheel.
Our advice: a bike rack is an easy way to transport your mountain bike without dirtying your car.


The ST 120 mountain bike comes with a bell, lights, wheel reflectors, and pedals.

The frame is compatible with:
-300 central stand (ref. 8172767) and 500 central stand (ref. 8172769)
-100 bottle cage (ref. 8049106) and 500 bottle cage (ref. 8358133)
-Mountain bike mudguard set (ref. 8385291)
-100 saddle bag (ref. 8347394) and 500 saddle bag (ref. 8354448)
-500 pannier rack (ref. 8364376)
-100 frame child seat (ref. 8486913 and 8487125), from size M


Lifetime (frame, stem, handlebar). Availability of spare parts: 2 years.


S - 155-164cm : 15.1 kg
M - 165-174cm : 15.2 kg
L - 175-184cm : 15.3 kg
Weight without pedals.

Product concept & technology

Product Composition

Frame 100% Aluminium


After washing, rub with a dry cloth to remove all traces of moisture. Store your mountain bike in a cool, dry place, away from corrosive products and salty air.

User Directions

Not suitable for XC, All Mountain, Enduro and BMX.


Our engineers always have real riders test all our products in real conditions. These tests round out our lab tests and let us validate all our products before they hit store shelves.


To have more informations about this product, consult the notice



Q:How to assemble your bike?

A: Everything you need to know about making sure your bike is comfortable, secure and ready to ride.

Q:Do you offer a Cycle To Work scheme?

A: Find out everything you need to know about way of getting to work that’s for good you and the environment. Check Here
Products sold and shipped by Partners are not eligible for Cycle to work Schemes

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