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Rockrider ST 900 Kids' 24-Inch 9-12 Years Mountain Bike - Red

Sale price: Dhs. 1,750.00 Regular price:
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Sale price: Dhs. 1,750.00 Regular price:
Model: 8405170

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A photo of the Rockrider ST 900 Kids' 24-Inch 9-12 Years Mountain Bike - Red in use

Rockrider ST 900 Kids' 24-Inch 9-12 Years Mountain Bike - Red : We've designed this mountain bike for children aged 9 to 12 years (135 to 150cm) wishing to perfect their MTB techniques.

We've equipped this 24-inch mountain bike with an aluminium frame to make it lighter so children can take on any obstacle. The suspension fork and disc brakes mean they'll be able to go anywhere.

Ease of use

ALU frame and chainset for less weight.Quick release for removing the wheels.

Brake control

Front/rear mechanical disc brakes: powerful braking in all conditions


Suspension fork. Skinwall tyres for less weight, with side knobs.

Cycling comfort

Sports saddle combined with an aluminium seat post for greater comfort

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Product Reviews

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297 reviews

Rockrider ST 900 Kids' 24-Inch 9-12 Years Mountain Bike - Red
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My little boy advanced his riding skills so quickly on this bike, it was just perfect for him. He is a tall 7 year old and this was his first bike with gears, they were so easy to use he took to it straight away.

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This bike is the business!

Bought this bike for my 9 year olds birthday. Wanted a lighter weight bike for him. It is extremely well made. It helps that it is checked over by the Decathlon staff which is a bonus. The great thing about this bike is the disc brakes. These will give my son extra confidence when riding.

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Great bike for my 9 years old

Great value as always, disc brake and nice quality bike.

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He loves it

Bought for christmas and my son (6yrs) absolutely loves his new bike, top of his christmas presents! Set up by the team at Decathlon Gateshead, it's been stored until Christmas Eve, and he launched himself at it on the big day. Within an hour of being awake, he was outside. First bike with gears, gripshift makes this so easy for him, the size is perfect and he was off zooming up and down the street with ease. The next day, we went out further, confident and riding well, the bike handles the riding. Next, we'll be hitting the trails.

Rockrider, 24in Wheels,

Great bike for the price, sadly I think the chain is too short, will pop in in Jan to sort it.

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Click and collect

We where met with very friendly staff and given great service. My grandson will enjoy his Christmas present

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Rockrider ST

Bought as a Christmas present for my son, delivered fast with minimal assembly, it’s a great quality bike. expect to pay twice as much from a high street bike shop ! Spot on Decathlon

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It’s good, but not great.

First off, I went to pick the bike up. I turned up at the store to find it had already been built. I was not made aware of this as I wanted to build it with my son himself, plus, it would have been much easier to transport and wrap for Christmas. Decathlon, you need to give people the choice. So that aside, it’s not a bad bike. Looks nice, although the frame design is a little dated and the head angle could do with being a bit slacker. It mentions in the advert that it has oversize handlebars. They’re really not oversize at all, they are 2cm wide than my sons current 20 inch wheel bike. This bike could do with around 580mm bars at the minimum. Grips are OK but quite smooth so will be terrible when wet. Tyres are a hard compound, so they’ll likely last a while, but grip wise they’ll not be great. They could also do with being 2.1 wide rather than 1.95 which looks quite skinny on a bike of this size. Brakes are budget, but do a decent enough job of stopping. I don’t see them lasting too long though due to the quality. It shifts quite nicely to be fair, and has actual thumb shifters rather then those horrible twist shifters you see on most kids bike, so it’s a thumbs up for that. This bike would benefit from a smaller chainring though to give more climbing power. Weight? Well, they advertise 12kg, it’s more like 12.5 on the scales I used. Still light though and I’ll lose half a kg just upgrading the heavy tyres. Suspension is where I was most disappointed to begin with. OK, I expect cheap spring forks, but I expect them to actually work. They were very stiff, almost like they were getting stuck on the stanchion covers. I ended up having to service the forks (completely take them apart) and lube the stanchion covers along with all moving parts. Now that has been done they are a lot smoother, but should have been like that in the first place. Upgrade the tyres and bars, service the forks and you’ll be fine.

Brilliant bike

Brilliant bike for my son we went on a 10 mile bike ride tonight I must point out yes the stores first day back open was today and as expected it was busy outside and inside what I'm concerned for is the staff especially in the warrington store where I was I could here a few of them talking saying they had not stopped for a break I hope this gets sorted asap as the staff in that store are very good at there job and helpful having them disposals masks on for me was not ideal in the heat but that's upto you good luck good store.

Very very heavy

The frame is made of steel. It is a very heavy bike. Not ideal for any sort of hill and given that its marketed as a mountain bike....

Thank you for taking the time to review the ST 900 24" MTB.
I can confirm that the frame is made of aluminium and the total bike weighs 12kg.
In the spring of 2021, we will be launching another model called the ST 920 24" MTB which comes with hydraulic disc brakes, lighter air forks and finishing kit.
Your comments are taken on board and will be forwarded on to the team at Rockrider.
Peter, Cycling Manager, DECATHLON
Great kids bike

Wait till he see it !

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Перфектен велосипед

Много добър велосипед с възможности над средния клас.

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Dětské kolo

Kvalitní lehký rám, bez přesmykače- jednoduché na ovládání. Konečně jsem našel kolo bez řazení revoshift. Dále kotoučové brzdy- sice mechanické, ale plně dostačující. Potěší i přední a zadní světlo.

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S tímto výrobkem jsem velice spokojená

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Dcera je z kola nadšená.

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Additional Product informations



  • 100% Aluminium

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.

Controlled braking

Brake effectively thanks to the mechanical disc brakes at the front and rear.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 8 speeds. The single 36-tooth chainring and 11-34 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 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. Suntour fork with 50 mm of travel.

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 chain guard prevents the chain from derailing.

Double-walled rims and skinwall tyres

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.The tyres use SkinWall technology. This process allows you to reduce their weight, therefore increasing performance, grip and comfort.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 mmSeat tube length: 345 mmChainstay length: 415 mmSeat post length: 370 mmHead angle: 68.2°

Item may differ from photograph

For the drive train parts (cassette and derailleur), the photos and videos provided on the product description show a Shimano Altus derailleur and a Microshift cassette. However, because of procurement issues, an equivalent, Microshift derailleur and cassette may be present on the bike.

Care instructions

In order not to damage your bike, we do not recommend the use of a high pressure cleaner. Rinsing with clear water and a sponge is preferable.

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