Product Colors and Sizes

  • Black Friday product
  • New Deal product
  • Cyber Monday product
  • Clearance product
  • Deal product
  • Best Seller product
  • Ecodesign product
  • New product
  • Staff Pick product
  • In The News product
  • Innovation product
  • product

Rockrider ST520 Mountain Bike 27.5"

Sale price: $250.00 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.

Color: Select a color
Size: Select a size
Size Guide
Sale price: $250.00 Regular price: $499.00

See shipping rate at checkout

Final Sale: No returns or exchanges

See our return rules for heavy items

Free pickup

San Francisco, 735 Market St. Options

Select an available color and size to see options.

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

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

Skip to reviews
3025 Reviews
Write a Review 

Rockrider ST520 Mountain Bike 27.5
Filtered by reviews Loading reviews…

It’s pretty and easy to ride. However, there is little difficulty changing the speed for my bike, and the bell is little bit far from the hand.

Mountain bike

Good bike, very easy to put together (minimal build required) only just started to use it due to better weather, too early to tell if it stands the test of time, but so far so good.

icon-circle-checkmark verified purchase
Awesome bike

Great service and high quality bike - son (12) is very happy with it

icon-circle-checkmark verified purchase

Very good

icon-circle-checkmark verified purchase
Awesome bike

Really like it, no problems as yet, happy

icon-circle-checkmark verified purchase

Bought this bike but the right pedal wouldn’t tighten therefore cross threading the right crank arm now I have to go pay 45 pounds to get the bike check and make sure it’s say to ride aswell as rethredding the right crank arm. Very poor

icon-circle-checkmark verified purchase

Very good love it, I’m no professionals cyclist but all good so far

icon-circle-checkmark verified purchase
New 520 MTB

This bike is great value and more than I expected in terms of quality.

icon-circle-checkmark verified purchase

Chain broke after a week of us seat lose not the best for money no shop opened by where we live to sort out

icon-circle-checkmark verified purchase
Great value for money

Although I haven't had the bike for long, I've been very impressed so far. The spec offers great value for money and (touch wood) have had no problem keeping up with the kids on trails.

icon-circle-checkmark verified purchase
Great bike

Well...people bitch about cheap bikes....But sometimes you don't get what you pay for! I looked for a mtb that did not cost to much but was worth buying and came across this bike. I have to say it is well made....looks great and worth every penny. It looks amazing but the stickers on the forks and wheels are not for me and the reflectors in the wheels so i removed them and now the bike looks less bling! It rides great and feels great. Well worth the money.

icon-circle-checkmark verified purchase
Really good bike

I really enjoyed this bike, but I think that it would be better if it had more colour options

Rock rider

Bike is a good bike for starting into serious biking but pedals bit cheap easy to replace tho

icon-circle-checkmark verified purchase
Great bike for the money

I wanted a bike to cycle the cycle paths of Hertfordshire, the odd trip to Thetford Forest and the odd trip up north. Great fun, perfect for what I want it for.

icon-circle-checkmark verified purchase
I love the bike

The bike is soo great thanks

icon-circle-checkmark verified purchase
Skip to reviews

Size Guide

Size Guide Visual

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


Size Guide Visual

Please Sign In to Post Your Question

In order to notify you about the answer it is required to Sign In.

Sign In