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BTWIN Rockrider ST 920 Kids Alloy Mountain Bike - 24"

was £399.99 -%


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
£399.99 -%
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
Check availability in store
We've designed this mountain bike for children aged 9 to 12 years (135 to 150 cm) who want to perfect their MTB skills. Equipped with the same aluminium frame as the 24" ST 900, this mountain bike has an air suspension fork to adjust to the child's weight and hydraulic disc brakes for effective downhill braking
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 and you might not be able to process your order at checkout. The count resets at 11pm every day so that would be the best time to try, although we do have a peak of attempts at this time so we can't guarantee a slot for everyone.

Product benefits

Ease of use ALU frame and chainset for less weight.
Quick release for removing the wheels.
Brake control Front/rear hydraulic disc brakes: POWERFUL AND PROGRESSIVE BRAKING
Efficiency Air suspension fork, Skinwall tyres for less weight, 9 speeds
Cycling comfort Sports saddle combined with an aluminium seat post for greater comfort

Technical Information

A frame that is suitable for mountain biking.

Our engineers have designed a new aluminium frame. Durable, lightweight and responsive: designed for tackling any obstacles when out mountain biking.

Don't be scared of riding downhill!

Powerful, progressive braking thanks to the front and rear hydraulic disc brakes.
The disc brake acts on the wheel axle to deliver powerful braking under any conditions (dry, wet, muddy, etc.).

Single chainring drivetrain

This bike is equipped with speed controls that are controlled using the thumb and index finger, allowing effortless changes between the 9 speeds. The 36-tooth single chainring and 11-36 cassette make it easy to shift gears and deal with any kind of hill. With just one control to manage, you can focus on your trajectory.

Front air suspension for cushioning on uneven terrain

This 24" ST 920 bike comes with an air fork that adapts to the child's weight.
Take on new challenging terrain (roots, stones, gravel, etc.) with ease thanks to the travel of the front suspension fork.

Comfort when riding

A saddle with a sporty design, designed with care to adapt to the morphology of children. Combined with an aluminium seat post (sturdy and flexible) for even greater comfort.

Riding position

To hone your steering, we have equipped this mountain bike with a short aluminium stem (70mm) and a 540 mm oversize handlebar. This makes you more precise and responsive on turns.

Aluminium chainset

The new aluminium chainset has a 152 mm crank that is suited to the child's leg length. This light chainset allows you to start pedalling more easily.
The double guard over the chain stops it jumping.

Double-wall rims

The double-walled aluminium rims are light and durable.
For transporting the bike, we've made it easy to attach/detach the front and rear wheels. They are equipped with a quick-release system.
24-inch 1.7 to 2.2 cross-section inner tube with Schrader valve. Pressure indicated on the tyre sidewall (between 2 and 3.5 bar).

Bike accessories

This MTB is equipped with a bell, lighting, wheel reflectors and platform pedals.
The frame is also compatible with other B'Twin accessories:
- front and rear mudguards
- stand
- bottle cage
- bag

Dimensions of the bike ready to use

Length: 160cm.
Height: 100cm.
Width: 60cm.

Frame dimensions

Top tube length: 479.3 mm
Seat tube length: 345 mm
Chainstay length: 415 mm
Seat post length: 370 mm
Head angle: 68.2°


12 kg

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Composition / advice

100.00% Aluminium
Stock advice Store the bike in a clean, dry place. Clean and grease the chain regularly. Our tips for before each ride: inflate the tyres to the pressure indicated on the sidewall.
Restricted use : Wearing a helmet is required.

Our commitments

Guarantee : Lifetime (frame, stem, handlebars). Find out more about the bike guarantee.


Q : How to assemble your bike?
Everything you need to know about making sure your bike is comfortable, secure and ready to ride.
Q : How do you adjust your brakes?
Having properly functioning brakes is vital when out on the road. Check out how to get them working to your liking.
Q : How to replace a brake lever on a bike?
Having properly functioning brakes is vital when out on the road. Here’s a video to show you how to make sure your new brake level is working nicely.
Q : How to replace a disc brake?
Having issues with your disc brake? Then this video is for you.
Q : How to adjust your bike handlebar?
A suitable handlebar height is essential to your cycling safety and comfort. Find out how to adjust it to your liking with our video.
Q : Do you offer a Cycle To Work scheme?
Find out everything you need to know about way of getting to work that’s good you and the environment.Check Here

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Our services

Mountain Bike Rockrider ST 920
Maintenance and repair
Maintenance and repair
Spare parts