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B'TWIN Rockrider ST 500 Kids Mountain Bike, Yellow - 20"

until £149.99 -%


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

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* Sales from to Until end of stock
* From and limited stock
£149.99 -%
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
Perfect for regular mountain bikers aged 6 to 9 years old (120–135 cm tall), the B’Twin Rockrider ST500 has 6 speeds which, when combined with its front suspension fork, make it easy for younger riders to overcome rough and hilly terrain. Designed with a grip shifter for easy gear changing, it’s a bike that makes mountain biking safe, simple and fun.
  • Sturdy steel frame
  • Ergonomic saddle
  • 20-inch wheels
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

Ease of use Equipped with a grip shifter to easily change gears (6 speeds
Brake control New Easy break brake levers are sized for children's small hands.
Efficiency Suspension fork. Skinwall tyres for lower weight, with side lugs
Cycling comfort A saddle with a sporty design, sized especially for children.

Technical Information

Frame designed for mountain biking

Our engineers have designed a new sturdy steel frame. The frame's rear chainstays are short, making the bike responsive and easy to handle.

Front suspension to cushion unpredictable terrain

Take on new challenging terrain (roots, stones, gravel, etc.) with ease thanks to the travel of the front suspension fork.

Changing gear

This bike is equipped with a grip shifter to change between the 6 speeds: an easier, safer system as the child's hands stay on the handlebars.
This makes changing gears to match the terrain simple and easy !

Controlled braking

Two V-Brake pads for effective braking.
These brakes are composed of callipers that exert more or less pressure on the rim to slow or stop the rotation of the wheels.

A reinforced, ergonomic saddle

A saddle with a sporty design, designed with care to adapt to the morphology of children. It is equipped with a plastic section on the rear (a bumper) to protect against any impacts.


The new chainset has a 140 mm crank that is designed for a child's leg length. This chainset allows you to start pedalling more easily. The crank is covered to prevent the child from coming into contact with the metal part.
The double chain guard prevents the chain from derailing.

Riding position

When mountain biking, it is important to control your path. To make it easier for children to learn, our engineers installed a handlebar and stem that are combined into a single steering block. This eliminates the needs for adjustments, so they can stay focused on the road!

20" wheels and MTB SkinWall tyres

The tyres are designed for mountain biking. The lateral lugs provide good grip on turns. The tyres are made with SkinWall technology. This process makes it possible to reduce their weight, provide greater flexibility, therefore increasing their performance, grip and comfort.
The recommended tyre pressure is indicated on the side of the tyre (2 to 3.5 bars). 20" inner tube, 1.7" to 2.2" Schrader valve.

Bike equipment

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 holder; - bike bags; - stabilisers

Dimensions of the bike ready to use

Length: 140cm.Height: 80cm.Width: 54cm.


14.3 kg

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Composition / advice

Frame (for bike)
100.00% Steel
Stock advice Store the bike in a clear, 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 : Wear a cycling helmet while riding.

Our commitments

Guarantee : To ensure riders can easily overcome rough terrain, we've equipped this 20-inch MTB with a suspensio

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