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ROCKRIDER ST 100 Women's Mountain Bike, White - 27.5"

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until £179.99 -%


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

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£179.99 -%
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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Have fun as you tackle small obstacles in the great outdoors, whether it's your first mountain bike adventure or you're still getting a handle of the off-road experience with the Rockrider ST 100. Comfort is the priority - check out the CGF frame with raised position, 80mm suspension, women's hammock saddle with Flex seat post and 27.5" wheels (26" in XS) - but speed isn't far behind (there are 21 and the grip shifters make them quick to switch between).
  • Light frame with raised position for comfort and control
  • Precise breaks and lugged tyres
  • 80mm suspension
Not Available Now

We currently have limited capacity to build bikes in our warehouse. Due to this, we are limiting the number of bikes we sell per day. If you are unable to process your order at checkout, please return the following day to make your purchase.


Product benefits

Anatomic design Y Feminine comfort: saddle, adjustable fork, raised position, closely-spaced brake
Durability Reinforced mountain bike: double-walled rims, welded saddle, derailleur guard.
Efficiency Fly along with the light frame, 21 speeds, 27.5" (XS 26") wheels & rolling tyres
Ease of use Change speeds quickly: grip shifters & closely-spaced brakes.
Lifetime warranty ROCKRIDER offers a lifetime warranty on the frame, handlebars and stem.

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 has studied the features of female body shapes and used this to design and test the ST 100, involving young mountain bikers at every stage of the process.
Our aim is to make you want to jump onto your comfortable, easy-to-use mountain bike so that you enjoy every one of your rides.


We have carried out research to give you a mountain bike designed for your body shape. We performed studies with the DECATHLON Sports Lab and user tests with mountain bike fans. After six months, this was the result: a mountain bike whose position was designed for women!
What does this mean?
- An ergonomic saddle for women's hips.
- A fork that adjusts to your weight
- A shorter, adjustable stem
- Less space between the handles and brake levers
- An XS frame (1.45m)


Here is our mountain bike size guide!
XS: between 1.45m and 1.54m
S: between 1.55m and 1.64m
M: between 1.65m and 1.74m
L: between 1.75 m and 1.84 m
Here are our tips on adjusting the mountain bike to your height:
1/ When sitting on the saddle, you should be able to touch the ground with the tips of your toes.
2/ To set the saddle height, your knee should be slightly bent when your foot is in the pedal in its lowest position.
3/ If you are between sizes, opt for the bigger 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.


You can adjust how stiff the suspension is, from 45 to 80kg, on the fork based on your weight so that roots and stones are easier to get past. It's all thanks to the UFIT technology (an exclusive DECATHLON patent). Easy: simply turn the dial!
The 80mm 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 x 7 speed chainwheels, 21 speeds total!
2 easy-to-use grip shifters on the handlebars.
Left (chainwheels): control ascents/descents.
Right (speeds): more precise control over your pedalling.
In detail:
-Triple-chainwheel chainset (22/32/42 teeth)+ anti-grease protection.
-Microshift FD-M20 front derailleur
-Microshift RD-M25 rear derailleur
-Microshift MS25 grip shifters with speed indicators
-Shimano TZ500 7 cog cassette, 14 to 28 teeth
-Large, solid KMC Z51 chain


The 60mm-long aluminium stem, which is specially designed for women's bodies with its 10° angle, gives you maximum comfort. The 620mm-wide steel handlebar provides stability and control. 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 adjusts in one motion

Exclusive "COMFORT" women's saddle designed to suit women's hip shape. It is slightly wider, in the shape of a hammock, and flared in the centre to make it more comfortable to sit on. Want an even more comfortable saddle? Add a saddle cover. There is a simple adjustment lever so that you can change your saddle's height quickly and without tools.


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 2 V-brakes are composed of callipers that exert pressure on the rim to slow or stop the rotation of the wheels. You only need two fingers to brake. Check how the pads are wearing once per year. If the grooves are disappearing, take your bike to your local store's workshop.

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

Take on your first obstacles! The wheels are effective and sturdy: 27.5", double-walled rims, 28 spokes (26", single-walled and 32 spokes in XS). The rim is lined for added durability and shock absorption. The DRY 27.5 x 2.0 tyres offer optimal performance with a rolling central part and knobs on the side to grip the ground on corners.


The Rockrider ST100 mountain bike comes with resin platform mountain bike pedals for added light weight and safety. If your foot slips off the pedal, there's less risk of bruising your shin.


Not all rides start on your doorstep. Need to take off the front wheel? Simply unscrew the built-in clamping lever. And what about the back? A nut allows you to secure your bike to reduce the risk of theft.
You'll need a spanner to remove it. A bike rack is a good idea to stop your car getting covered in muck.


Your ST 100 mountain bike comes with a derailleur guard, chainwheel guard (to protect your clothing from dirt), bell, lights, wheel reflectors and pedals.
Other accessories available:
-Front and rear mudguards (Flash MTB or 700 MTB)
-Stand (500 Adult Base)
-Bottle cage
-Saddle bag
-Rear pannier rack
-Child seat (Polisport Groovy frame mounted)
You can find all of the item codes on our after-sales support website.


We recommend that beginners wear cropped bottoms or cycling shorts with a pad (foam in the shape of a saddle) or a gel saddle cover to reduce soreness. For long rides, it's always a good idea to take a drink with you (e.g. hydration pack or water bottle).
And our last bit of advice is a style tip: in all circumstances, even for a short ride, wearing a helmet and gloves is essential in case you take a tumble!

Easy-to-read stickers

Have you spotted the colourful stickers on this mountain bike? They're not just there to add a touch of pink.
They are resistant to wear and provide markings to help you adjust your bike: fork, tyre pressure, rim diameter, saddle height, etc. When you head out on a tour, it's handy to have instructions on the bike itself!
And for all other info (rinsing, chain maintenance, etc.) visit our support page :)


XS - 140-154cm: 15.3 kg
S - 155-164cm: 15.4 kg
M - 165-174cm: 15.5 kg
L - 175-184cm: 15.6 kg
XL - 185-200cm: 15.8 kg

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How has this product been built

Composition / advice

Frame (for bike)
100.00% Aluminium
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.
instructions To get more information about this product, please read instructions
Legal notice The bike's weight can vary based on the tolerance of the components. The total weight (bike + rider) should not exceed 120kg.

Our commitments

Test Product Our engineers have all of our products tested by young mountain bikers in real conditions. These tests complement the tests we do in the lab and mean that we can approve our products before they go on sale.
Guarantee : Lifetime (frame, stem, handlebars). Availability of spare parts: 2 years.

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ST 100 27.5
Maintenance and repair
Maintenance and repair
Spare parts