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ST 520 Women's Mountain Bike - 27.5"

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was £279.99 -%


This price includes a recycling fee for electrical equipment and batteries DecathlonDeeeTaxMentionAfterPrice / Since

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£279.99 -%
This price includes a recycling fee for electrical equipment and batteries DecathlonDeeeTaxMentionAfterPrice / Since

* From To

* Sales from to Until end of stock
* From and limited stock
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Recommended for women seeking their first proper 27.5-inch hardtail mountain bike, the Rockrider ST520 has an exclusive Evo alloy frame to guarantee great performance. Featuring a raised position, comfortable ergonomic saddle, Hayes MX5 disc brakes, full SRAM 24-speed groupset and low rolling resistance, it’s the full package.
  • Double-walled aero 27.5-inch wheels for comfort
  • Low rolling resistance
  • Suitable for rough terrain and all weathers

Technical Information


This mountain bike was fully designed and developed at the B'Twin Village (Lille, France) and is the brainchild of an expert team of mountain bike enthusiasts.
The team observed and studied the differences in women's body shapes to design, develop and test the ST 520, gathering input from women mountain bikers at every stage of the project.
Our goal is to make you want to ride and enjoy every single outing on a comfortable and easy-to-ride mountain bike.


To create a mountain bike designed especially for women, we dove deep into the issue. We carried out studies with the DECATHLON Sports Lab and usage tests with hardcore mountain bikers. After six months, we came up with a mountain bike that's perfect for women!
What does that mean exactly?
- An ergonomic saddle to fit a woman's body.
- An adjustable fork based on your weight.
- A shorter, adjustable stem.
- A shorter distance between the grips and brake levers.


This is our guide for MTB sizes!
S: between 1.50m and 1.64m
M: between 1.65m and 1.74m
L: between 1.75m and 1.84m
To adapt your MTB to your height and size, try these tips:
1/ Sitting on the saddle, your 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.


Because we've noticed that it's not always easy to get the right position on a mountain bike, our designers have created an entirely new frame that's easy to get onto.
The CGF frame (Comfort Geometry Frame) is 100% aluminium for optimal comfort and excellent manoeuvrability. The slope angle has been designed to keep your back straight whilst the low rear ensures the bike is very agile when turning.


Adjust the suspension hardness based on your weight, from 45 to 80 kg to get over roots and stones more easily. This is all thanks to the UFIT concept (exclusive to Decathlon).
Easy: simply turn the adjustment wheel!
The 80 mm front suspension is designed for slightly uneven trails and helps you overcome your first obstacles with no worries.
Its design, based on a mechanical spring, is reliable and easy to maintain.


3 8-speed chainwheels, or a wide range of 24 speeds.
2 quick shifters on the handlebar.
Left (chainwheels): control ascents/descents.
Right (speeds): more precise control over your pedalling.
In detail:
- Triple chainwheels - 22, 32 and 42 teeth
- SHIMANO Altus or MICROSHIFT MS22 front derailleur
- SRAM X3 rear derailleur
- SRAM X4 shifters, with speed indicators
- SRAM PG820 8 cog cassette, 11 to 32 teeth


The 60mm-long aluminium stem, which is specially designed for women's bodies with its 10° angle, gives you maximum comfort. The 660mm wide steel handlebars ensure control and stability. And the soft touch handles, for good grip, are comfortable to hold.
To adjust the bike even more accurately, you can move the spacer (the coloured ring) to adjust the stem's height, or put it back on to raise the position.

An ERGONOMIC SADDLE that can be easily adjusted

An exclusive "COMFORT" saddle designed especially for a woman's body. The wider, hammock-style design is hollowed out in the centre for comfort. Want an even comfier saddle?
Add a saddle cover. Adjust your saddle height quickly and without tools thanks to the easy adjustment lever.

Mechanical disc brakes: GET A GRIP ON YOUR BRAKING

To adapt to girls' small hands, we have reduced the distance between the handlebar and the brake! With this better, more responsive position, you will gain confidence. The TEKTRO aluminium brake levers are easy to grip, lightweight, and precise.
The HAYES M-X5 mechanical double disc brakes give you gradual, powerful braking at the front and back. Just two fingers are all you need to brake.
Try to get your brakes adjusted at least once a year.

27.5" wheels & tyres for dry terrain: READY TO ROLL?

Take on your first obstacles! The Aero Trail Evo aluminium wheels are efficient and robust: 27.5" with double-walled rims. Their diameter offers an excellent balance between performance and comfort. With their 28 spokes, they are lightweight, stiff, and durable.The exclusive 27.5" x 2.0 B'TWIN ALL TERRAIN DRY tyres are designed for dry terrain. Their side lugs provide good traction during turns. The recommended tyre pressure according to the weight of the rider is marked on the tyre sidewall.


The ST 520 is supplied with platform MTB pedals mounted on bearings, made from resin for light weight and safety. If your foot slides on the pedal, there's less risk of injury.


Not all rides start on your doorstep. This is why we've made it easy to remove and attach the front and rear wheels. They are equipped with a quick-release system.A bike carrier will make your life easier if you want to avoid dirtying your car.


Your ST 520 mountain bike is supplied with a bell, lights, wheel reflectors and pedals.
The frame is compatible with:
- front and rear mudguards,
- stand,
- bottle cage,
- saddle bag,
- rear pannier rack,
- child seat (add an additional pannier rack for sizes S and M to avoid touching the rear wheel)


If you're just starting out, we suggest wearing cropped bottoms, shorts or cycling tights with a pad (foam in the shape of the saddle), or using a gel saddle cover to enhance your riding comfort. For longer rides, it's always a good idea to take something to drink (eg, a hydration backpack or bottle).
One last tip for safety: You should always wear a helmet and gloves, even for a short ride, in case you fall!

Stickers for an easy-to-understand MTB

Did you notice the coloured stickers over your mountain bike? Don't worry, it's not to add a touch of pink.
Resistant to wear, they provide hints on how to adjust your bike: adjusting the fork, tyre pressure, rim diameter, saddle height... When you head off on a ride, it's always useful to have the instructions directly on your bike!
For other information (washing, chain maintenance, etc.), read our support file :)


S - 155-164cm: 14.35 kg
M - 165-174cm: 14.45 kg
L - 175-184cm: 14.55 kg

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Composition / advice

100.00% Aluminium 6061
Stock advice 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.
Restricted use : Not suitable for XC, All Mountain, Enduro and BMX.
Legal notice Your bike's weight may vary due to tolerances in the components.
The total weight (bike + rider) should not exceed 120kg.To find out more about usage and maintenance information of the SUNTOUR fork, go to the SUNTOUR website.
You will be able to download the instructions manual for your component from this website.

Our commitments

Test Product Our engineers have extensively tested our products with female MTBers under real conditions. These tests round out our lab tests and let us validate all our products before they hit store shelves.
Guarantee : Lifetime (frame, stem, handlebars). Availability of spare parts: 2 years.

Product benefits

Anatomic design Y Comfort for women: saddle, adjustable fork, raised position, closer brakes
Precision Manage your path: double disc brakes and notched tyres on the sides.
Efficiency Smooth riding: light frame, 24 speeds, 27.5" wheels, low rolling resistance.
Ease of use Y Adjust the fork using a dial from 45 kg. Adjust the saddle with one movement.
Lifetime warranty Y ROCKRIDER offers a lifetime warranty on the frame, handlebars and stem.

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ST 520 Women's Mountain Bike - 27.5
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Maintenance and repair
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