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Rockrider ST520 Mountain Bike 27.5"

Sale price: $150.00 Regular price: $499.00

Raised position., stem can be raised up to 1.18 in., ergonomic saddle: comfort that also yields greater efficiency. 27.5" wheels, double disc brakes, 24 speeds.

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Sale price: $150.00 Regular price: $499.00

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Final Sale: No returns or exchanges

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San Francisco, 735 Market St. Options

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About this item:

  • Rockrider CGF Evo (Comfort Geometry Frame) 6061 aluminum frame
  • Light, 27.5” Aero Trail Evo wheels
  • 24-speed SRAM X3
  • SRAM S200 triple-chainring chainset
Model: 8629918

Product Videos

Product Features

A photo of the Rockrider ST520 Mountain Bike 27.5" in use
A photo of the Rockrider ST520 Mountain Bike 27.5" in use

Rockrider ST520 Mountain Bike 27.5" | sporty mountain bike rides.

Raised position., stem can be raised up to 1.18 in., ergonomic saddle: comfort that also yields greater efficiency. 27.5" wheels, double disc brakes, 24 speeds.

Cycling comfort

Raised position. Ergonomic saddle. Height-adjustable stem. Soft-touch grips.


CGF Evo aluminum frame. 24-speed SRAM X3. Light, 27.5” Aero Trail Evo wheels.


Dual disc brakes. Easy handling frame geometry. Tires have good grip in turns.

Easy to use

Innovative fork with easy adjustment based on rider's weight.

Questions & Answers

Product Customer Reviews

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Rockrider ST520 Mountain Bike 27.5
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Gifted for my son

He is delighted

Great bike


Good material and very good value for money


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cheap good

A cheap and good bike for commuting to work and occasional rides around the city, the more you ride the more you want better equipment :D I recommend everything works after 3 years

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still problems

very disappointed once again after the wheel problems, premature wear of the chain, the chainrings and the crankset hub, we realize that the water and the mud pass through the seat tube and go down to the hub wears out the frame and the hub I thought engineers thought the best for the design they don't think much of course so disappointed haven't been going to decathlon for a long time

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Bikes for beginners or for those without pretensions

Excellent MTB with a really low cost, ideal for beginners or for those who have no pretensions. As mentioned, it's a very entry-level bike, it's great for taking walks on the road, for light dirt and white roads. It does its thing and does it well, it controls well on the narrow streets and the gearbox is also effective and precise. The front suspension is there but on dirt roads with stones etc it immediately exceeds its limits, I recommend changing the saddle as soon as you can. You feel the weight going uphill a bit, but in any case for what you pay you can't complain, the brakes are good, but they often loosen and you have to tighten them, however they are effective and very gradual. As a defect I clearly feel like saying that the suspensions soon find their limit, the weight is there and you can feel it, and unfortunately the shipping service was quite bad, I received the bike with the box broken, without the hub pin front wheel, for which I had to wait several weeks before it was sent to me, too bad. In summary, therefore, it is a bike that quickly reaches its limits if you twist its neck a lot, but one could not expect otherwise given the cost of only 299 euros. I recommend it to anyone who wants to ride light dirt roads or some dirt descents, I don't recommend it to anyone who buys it and believes they have a MTB that can easily cover the most extreme trails. In general, really very positive opinion.

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Very good product. Light and handy

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A good opinion


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Do the job!

Top notch for the price. City use + country lane and hillsides.

Decathlon is no longer what it used to be!

After a few rides, a friend who bought the same model as me shows me the teeth of the chainring prematurely worn. I watch my transmission and a few outings later, several chain jumps when changing chainrings and here is my lower belly against the handlebars in the middle of a climb and several times .... it hurts !!! Brought back to the store, the transmission was changed and I decided to only use this bike on the road for a few rides. But today, the transmission still falls in curtain: my chain does not want to leave the small chainring ....... And the teeth which already show signs of weakness!!!!! For leisure, this mountain bike is not reliable, so for paths and forests ..... I will not risk it anymore .....

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The frame is guaranteed for life, it is the only element that will hold up over time. For the rest, very fragile elements, pedals, brakes .. Moreover quite heavy, really low-end, quite disappointed over time.

Very cool bike

Very good bike, too bad that the accessories (tires, brakes, etc.) wear out at the speed of light.

even git

I have the bike +/- for 2 years I took care of and respected this bike very much, but the derailleurs in this bike are so terrible that the bike ends up in the service at least once a month, recently the link broke and the indicator in the derailleur switch broke, which informs about the current gear after going down from the first a better small curb can be expected to deregulate or bend the hook. IN ONE WORD MASSACRE I RECOMMEND BUYING ROCKRIDER BIKES

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Excellent Value for money

I've been using the bike intensively for two years now and I've never had any problems. The changes and some components may leave something to be desired for the most demanding cyclists, but for a weekend MTB it is a sensational piece of equipment that I have no complaints about. It was, without a doubt, an excellent investment in leisure and health.

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Additional Product Information


Bike frame : 100.0% Aluminum


The RockRider 520 was designed and created in Suzhou, China, by a team of experts and cycling enthusiasts dedicated to designing our MTB Sport Touring line. Production was also done near Suzhou to be as close to our Decathlon stores as possible.


Rockrider CGF Evo (Comfort Geometry Frame) 6061 aluminum frame for 27.5” wheels.Comfortable seating position thanks to raised steering.Seat is 5 times more flexible than a standard frame thanks to a narrow 1.07-in. seat post.Low bottom bracket: helps keep the mountain bike stable in turns, and makes it easier to place foot on the ground.Open steering angle (69.5°): keeps mountain bike stable while riding.Short rear wheel base: bicycle is easy to turn.LIFETIME WARRANTY on the frame!

Front suspension

B'Twin U-Fit 80 fork, with 3.15 in. of travel and an innovative fork stiffness adjustment based on the rider's weight (121 to 230 lbs.). Durable thanks to the materials and fabrication processes used.Equipped with a mechanical spring and elastomer stoppers for maximum reliability and minimum maintenance.

Rear suspension

No rear suspension.


SRAM S200 triple-chainring chainset (22/32/42 teeth).SRAM X3 8-speed rear derailleur.Microshift MS22 front derailleur.SRAM X4 shifters with speed indicators.SRAM PG820 cassette, 8 cogs, 11 to 32 teeth.

Product testing

We also recommend that beginners wear cycling shorts with a protective pad and/or a gel saddle cover to reduce soreness.

Storage instructions

Store in a cool, dry place, away from corrosive products and salty air.



Superior quality. Unbeatable prices.

For 40 years, Decathlon has delivered the best value in the retail sports industry by offering high-quality, sustainable and cost-effective products.

Decathlon makes the difference
  1. product-research

    Research and development

    delivers high-quality cost-effective products

  2. State-of-the-art production processes

    minimize manufacturing costs

  3. Optimized supply chain

    reduces retail prices

  4. laptop-checkout

    Minimal retail footprint

    lowers overhead and indirect costs


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