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Mountain Bike Rockrider 520 - Dark Gray
Mountain Bike Rockrider 520 - Dark Gray
Mountain Bike Rockrider 520 - Dark Gray
Mountain Bike Rockrider 520 - Dark Gray
Mountain Bike Rockrider 520 - Dark Gray
Mountain Bike Rockrider 520 - Dark Gray
Mountain Bike Rockrider 520 - Dark Gray
Mountain Bike Rockrider 520 - Dark Gray
Mountain Bike Rockrider 520 - Dark Gray
Mountain Bike Rockrider 520 - Dark Gray
Mountain Bike Rockrider 520 - Dark Gray
Mountain Bike Rockrider 520 - Dark Gray

Mountain Bike Rockrider 520 - Dark Gray

27.5" wheels, double disc brakes, 24 speeds.

4.2 / 5

Regular price


B Twin

Mountain Bike Rockrider 520 - Dark Gray designed for regular, moderate intensity mountain bikers looking for thrills!

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: It has it all!
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.


Double disc brakes. Easy-to-handle geometry. Tires have good grip in turns.

Easy to use

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

Lifetime warranty

B’Twin provides a lifetime warranty on the frame, stem and handlebar.


The ROCKRIDER 520 was designed and created in France, at the B'Twin Village in Lille, by a team of experts and cycling enthusiasts dedicated to designing our mountain bike Sport Touring line.
Production took place in different factories in Europe as close to our Decathlon stores as possible.
More information available on our website:


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.

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.

Drive train

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.


Tektro aluminum brake levers: lightweight and precise.
Front and rear Hayes MX5 mechanical disc brake calipers: powerful, progressive braking, even in rainy and muddy conditions.


B'Twin Sport Oversize aluminum handlebar; 25.9 in. (Size S and M), and 26.7 in. (L and XL).
Exclusive B'Twin aluminum stem, 2.75 in. (Size S), 3.15 in. (sizes M/L), and 3.54 in. (size XL).
Stem can be raised by up to 1.18 in., with 5 settings (+ 0 in., + 0.29 in., + 0.59 in., + 0.89 in., + 1.18 in.).
Semi-integrated A-headset—better sealed and integrated style.
B'Twin Sport handles with grooves, 4.72 in. long: genuine comfort while riding.


Aero Trail Evo wheels with double-walled rims: lightweight, stiff, and durable.
27.5" diameter: the best balance of comfort and performance.
Designed with 28 spokes to reduce weight while still guaranteeing rigidity and strength.


Exclusive B'Twin All Terrain Dry 27.5" x 2.0 tires with a central tread specially designed for fast performance.
Side lugs provide traction in turns. Also includes a chart showing recommended pressure levels depending on the rider's weight (see markings on tire sidewalls).

Saddle / seat post

Exclusive B'Twin Ergofit Evo saddle offers outstanding comfort thanks to its wider "Hammock" cut and good distribution of pressure points regardless of the rider's pelvis width.
B'Twin Sport seat post in aluminum for less weight.
1.07-in. diameter provides the seat with a natural flex that's 5 times greater than a classic seat post.
15.75 in. long, offering a broad adjustment range.


Bike comes with MTB platform pedals with bearings, made from hard resin for lower weight and greater safety (less aggressive in case of pedal that slips).


31.63 lbs in S without pedals.
31.8 lbs in M without pedals.
32 lbs in L without pedals.
32.40 lbs in XL without pedals.


Frame can take a bottle cage, saddle bag, mud guard, stand, pannier rack.


S: 1.50m to 1.65m
M: 1.65m to 1.75m
L: 1.75m to 1.85m
XL: 1.85m to 2.00m

Product Testing

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




31.8 lbs in M w/o pedals


27.5 inches


frame, handlebar and stem


Frame : 100.0% Aluminium 6061


Not suitable for All Mountain, Enduro, BMX

Storage Instructions

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



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