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Rockrider ST520 Mountain Bike 27.5"
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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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
Product Videos
Product Features

Cycling comfort
Raised position. Ergonomic saddle. Height-adjustable stem. Soft-touch grips.
Efficiency
CGF Evo aluminum frame. 24-speed SRAM X3. Light, 27.5” Aero Trail Evo wheels.
Precision
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
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Product Customer 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.
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.
Great service and high quality bike - son (12) is very happy with it
Very good
Really like it, no problems as yet, happy
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
Very good love it, I’m no professionals cyclist but all good so far
This bike is great value and more than I expected in terms of quality.
Chain broke after a week of us seat lose not the best for money no shop opened by where we live to sort out
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.
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.
I really enjoyed this bike, but I think that it would be better if it had more colour options
Bike is a good bike for starting into serious biking but pedals bit cheap easy to replace tho
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.
The bike is soo great thanks
Size Guide

Additional Product Information
Composition
Bike frame : 100.0% Aluminum
Design
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.
Frame
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.
Drivetrain
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.
Origin
Imported
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
-
Research and development
delivers high-quality cost-effective products
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State-of-the-art production processes
minimize manufacturing costs
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Optimized supply chain
reduces retail prices
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Minimal retail footprint
lowers overhead and indirect costs

Rockrider ST520 Mountain Bike 27.5"
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Heavy products return policy
If you return a product you will receive a refund for the purchase price plus any applicable sales taxes, less any non-refundable charges.
Decathlon will cover all shipping costs associated with your return except for items excluded from our return policy such as bikes, basketball hoops, snowboards, surfboards, tents, and other larger / heavier items.
Return costs for heavy products:
Weight Thresholds | Shipping within California | Shipping outside of California |
---|---|---|
> 9 lbs | $20.00 | $25.00 |
> 30 lbs | $50.00 | $65.00 |
> 100 lbs | $100.00 | $125.00 |
> 200 lbs | $200.00 | $230.00 |
If you return a product at any of our store locations, we will gladly help you find the best alternative product or refund you on the spot.
