Mountain Bike S 27.5" ST 520

WHAT OUR TEAM HAS TO SAY

Our passionate MTB team has fully designed and developed the ST 520 S mountain bike at the B'Twin Village in France (Lille). We've designed, developed and tested the ST 520 S for comfort and efficiency. This combines to give MTBers confidence to overcome any new obstacle.

We have involved real MTBers at every stage of this bike's design process.

And we hope the that Rockrider ST 520 S is everything you could hope for to give you excellent MTB rides.

A UNISEX MOUNTAIN BIKE

Men's or women's mountain bike?

This Rockrider ST 520 S is unisex.



For greater comfort, the women on our mountain bike team recommend replacing the saddle with the Women's 500 Sport saddle, which is adapted to women's bodies.

A range of Rockrider mountain bikes specifically designed to fit female morphology is also available (specialized saddle, stem, fork and brake grips).

HOW DO I CHOOSE MY MTB SIZE?

Several sizes available:



S: between 4'11" and 5'5"

M: between 5'5" and 5'9"

L: between 5'9" and 6'

XL: between 6'1" and 6'7"



If you are at the limit between 2 sizes:

Choose the smaller size for easier steering (easier to handle) and comfort (straighter back).

Choose the larger size for easier pedaling with a more stretched-out position (position more suited to performance).

A LIGHT, COMFORTABLE FRAME

We've used 6061 aluminum for this Rockrider Sport frame for greater lightness. The result: only 6.4 lbs in size M (without shock). Its 120 mm rear shocks rest on a monopivot system (more sensitive to small impacts on terrain, while remaining firm during large impacts) and on sealed bearings for a great lifespan.

THE FRONT 120 MM SUSPENSION

The hydraulic 120 mm fork means you can easily ride over any obstacles (roots, rocks, stones, mud).



Directly adjust the stiffness of the suspension to your weight, from 120 to 230 lbs, to more easily travel over roots and stones. This is all thanks to the UFIT concept (exclusive to Decathlon).

Easy: simply turn the adjustment dial!

Built into the right damper, its quick-release system helps prevent bobbing on smooth sections.

THE REAR SUSPENSION: GREATER COMFORT

That is why our designers fitted the ST 520 S with a U-FIT hydraulic spring shock that is lightweight and specifically designed for this frame. You can easily adjust it based on your weight using the Schrader valve, which creates a very good balance between sensitivity and performance.

TRIPLE CHAINWHEEL DRIVETRAIN AND DERAILLEUR

3 8-speed chainwheels, or a wide range of 24 speeds!

2 quick shifters on the handlebar.

Left (chainwheels): control ascents/descents.

Right (speeds): more precise control over your pedaling.



In detail:



- Triple chainwheels 22, 32 and 42 teeth

- SHIMANO TX800 front derailleur

- SRAM X3 rear derailleur

- SRAM X4 shifters, with speed indicators

- SRAM PG820 8 cog cassette, 11 to 32 teeth

HANDLEBARS, STEM, GRIPS

The controls of the ST 520 S fall straight under your hands thanks to the adjustable stem. The all-aluminum B'Twin stem is 70 mm (size S), 80 mm (size M/L), or 90 mm (size XL) and can be raised using 5 adjustment intervals: + 0 mm, + 7.5 mm, + 15 mm, + 22.5 mm, + 30 mm.



In detail:

- Aluminum B'TWIN SPORT "oversize" handlebars are 660 mm (size S and M) or 680 mm (for L and XL) wide

- B'TWIN SPORT "soft touch" grips for a good grip and comfortable feel

COMFORTABLE, SPORTY SADDLE/SEAT POST

Our teams conceived and designed an exclusive saddle for this bike. Suitable for all hip sizes, its "hammock" shape is particularly good for sport touring.

With a 29.8 mm diameter and 400 mm long, the aluminum B'TWIN SPORT seat post combines low weight and a wide range of adjustments for a more raised riding position.

Quick and easy tool-free adjustment of your saddle height using the adjustment lever on the seat post clamp.

MECHANICAL DISC BRAKES: GET A GRIP ON YOUR BRAKING

The Hayes M-X5 160 mm mechanical double disc brakes provide powerful, progressive braking to the front and rear. While the aluminum Tektro brake levers are light, precise, and easy to hold. Just 2 fingers are all you need to brake.

Try to get your brakes adjusted at least once a year.

27.5" DOUBLE-WALLED RIMS and ALL TERRAIN TIRES

Take on obstacles! The aluminum Aero Trail Evo wheels are robust and effective: 27.5" double-walled rims. Their diameter is the perfect balance between comfort and performance. With their 28 spokes, they are lightweight, stiff, and durable.The exclusive B'Twin All Terrain Light 27.5" x 2.0 (rear) and 27.5" x 2.1 (front) tires have a system of lugs specially designed for all terrain use, to travel with you on any type of surface during your mountain bike touring.

PLATFORM PEDALS

The ST 520 is supplied with platform MTB pedals mounted on bearings, made from resin for light weight and safety. If your foot slides on the pedal, there's less risk of injury.

EASILY TRANSPORT AND STORE YOUR MOUNTAIN BIKE

Not all rides start on your doorstep. Need to remove the front wheel?

It's easy thanks to the integrated clamping lever. And the rear wheel?

There is a nut at the back to secure the bike and limit the risk of theft. A flat wrench is needed to remove the rear wheel.

A bike carrier will make your life easier if you want to avoid dirtying your car.

ACCESSORIES

Your ST 520 mountain bike is supplied with a bell, lights, wheel reflectors and pedals.



The frame is compatible with:

- front and rear mudguards,

- stand,

- bottle cage (500 ml bottle),

- saddle bag,

...

OUR ADVICE FOR YOUR FIRST FEW RIDES

Tip No.1

When mountain biking, there is always the risk of a fall: don't forget to wear a helmet.



Tip No.2

Even if the saddle is comfortable, cycling shorts with a pad (saddle-shaped foam) are a real plus for preventing glute pain.



Tip No.3

If you don't want to stop to drink, bring water in a bottle or water bladder to access it while riding.

Tip No.4

Punctures are always possible, remember to bring a repair kit.