B'Twin Rockrider ST 900 Kids 20" Mountain Bike

B'Twin Rockrider ST 900 Kids MTB

A few ST 900 Kids pics

Complete MTB specification

Designed for mountain bikers aged 6 to 9 years old (120-135 cm tall), the B'Twin Rockrider ST900 has 6 speeds which, when combined with its front suspension fork, make it easy for younger riders to overcome rough and hilly terrain.

Featuring a grip shifter for easy gear changing, it's a bike that makes mountain biking safe, simple and fun. Lightweight aluminium frame. Ergonomic saddle.

20-inch wheels.

Frame designed for mountain biking: Our engineers have designed a new aluminium frame.

Durable, lightweight and responsive: designed for tackling any obstacles when out mountain biking.

Controlled braking: Effective braking thanks to the cable-activated disc brake at the front and a V-brake at the rear. The disc brake acts on the wheel axle to deliver powerful braking under any conditions (dry, wet, muddy, etc). The V-brake is composed of 2 levers equipped with pads that exercise more or less pressure on the rim to slow or stop the rotation of the wheels.

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!.

Why have we created a brake lever specifically for children?: Because children have smaller hands than adults, it's not always easy for them to reach the brake lever. This is why our engineers designed a brake lever that is closer to the handlebars and thus easier to hold.

A reinforced, ergonomic saddle: 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: We equipped this mountain bike with a short aluminium stem (60 mm handlebar) and an oversized 520 mm handle for more controlled steering. This gives you greater accuracy and more responsiveness in the turns.

Aluminium chainset: The new aluminium chainset has a 140 mm crank that is designed for a child's leg length. This lightweight chainset allows you to start pedalling more easily. The double chain guard prevents the chain from derailing.

20" wheels and MTB SkinWall tyres: The tyres are designed for mountain biking. The lateral lugs provide good grip on turns. The tyres use 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 displayed on the tyre sidewall (between 2 and 3.5 bar). 20-inch 1.7"-2.2" wide inner tube with Schrader valve.

Bike accessories: This MTB is equipped with a bell, lighting, wheel reflectors and platform pedals.

Dimensions of the bike ready to use: Length: 140cm.

Height: 80cm.

Width: 54cm.

What if I order online?: For smoother shipping, our bikes come with their pedals removed and the handlebar unscrewed (instructions and tools are supplied).

Frame dimensions: Top tube length: 433.4 mm.

Seat tube length: 285 mm.

Chainstay length: 360 mm.

Seat post length: 300 mm.

Head angle: 69 degrees .

Weight: 11.7 kg.
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B'Twin Bikes

B'Twin are a popular choice of bike in the UK, partly due to their widespread distribution by Decathlon, and partly due to the value they offer. Their bikes are divided into several slightly overlapping ranges, with Triban best known for road and gravel bikes, and Rockrider gaining a reputation for high performing MTBs to suit every budget. Elops largely consist of a range of city bikes, whereas Riverside focus on hybrids. All in all, B'Twin bikes are well worth checking out given the size of their ranges; there's a model to suit most budgets.

Rockrider Mountain Bikes

Rockrider are Decathlon's off-road offerings, comprising of a series of kids bikes and adult hardtails, full suspension steeds and even a handful of high end E-MTBs.

This brand was launched in 2018, when Decathlon decided to split their B'Twin bikes into different genres. In terms of prices, there's something for everyone, with adult's MTBs starting at just over £200 and rising up to high end lightweight race bikes at nearly the £4000 mark.

If you want to ride off-road, and would prefer to buy from Decathlon, then the Rockrider mountain bike range is for you.