27.5 Inch Mountain Bike Rockrider ST 540

This 27.5″ mountain bike has been designed and developed to best suit mountain-bike rides lasting two to three hours, all year round, in any conditions.Discover the effectiveness and playful side of the ST 540 with 27.5″ double-walled rims, hydraulic disc brakes, and the simplicity of its 18-speed double chain wheels. All whilst staying comfortable.

Which is the right size?

Several sizes available:
S: between 1.50m and 1.64m
M: between 1.65 m and 1.74 m
L: between 1.75 m and 1.84 m
XL: between 1.85 m and 2.00 m

If you are between 2 sizes:
Choose the smaller size for easier steering (easier to handle) and comfort (straighter back).
Choose the larger size for easier pedalling with a more stretched-out position (position more suited to performance).

UNISEX FRAME

With a heavily sloped top tube and a wide range of sizes (from S: 1.50m to XL:2.00m).

The ST 540 mountain bike frame is UNISEX.

The ST 540 mountain bike is available with the same frame in a WOMEN’S version: fitted seat, narrower handlebar, shorter stem, fork with a more flexible spring, and brake levers that are closer together.

As a WOMAN, if you choose the MEN’S model, we recommend at least purchasing the WOMEN’S SPORT 500 saddle which is fitted to the female form.

A WORD FROM THE TEAM

The ST 540 mountain bike was fully designed and developed by our passionate MTB team at the B’Twin Village in France (Lille).

A comfortable, efficient mountain bike: more progressive, powerful hydraulic disc brakes, 100mm travel in the fork to easily ride over obstacles, and simple and effective double chainring,…
MTBers have been involved at every stage of this bike’s development process.

A COMFORTABLE, PLAYFUL FRAME

For less weight and more efficient pedalling, the Rockrider ST 540 MTB frame is made from 6061 aluminium (only 2.1 kg in size M).
Our designers created this bike to be comfortable and easy to manoeuvre. Its slope has been designed to keep your back straighter. The lower bottom bracket helps keep you more stable during turns.

100 MM FRONT SUSPENSION

Ride over obstacles with the hydraulic fork. Its 100 mm travel allows you to calmly overcome more obstacles (roots, pebbles, stones, mud).
Its built-in lockout system helps to prevent bobbing and loss of speed on faster terrain.

REAR SUSPENSION: None

This mountain bike has no rear suspension.

This is a “semi-rigid” mountain bike. Compared to a full suspension mountain bike (with rear suspension), the advantages are clear: this mountain bike is lighter; less energy is lost on flatter ground. If however your primary concern is comfort and manoeuvrability, the ST 540 is available in a full suspension version with suspension at the rear.

DOUBLE CHAINRING DERAILLEUR AND DRIVETRAIN

2 9-speed chainwheels for 18 easy-to-use speeds.
The thru-axle bottom bracket is very stiff and long-lasting.

In detail:
-SHIMANO Altus 22 and 36 tooth double chainring
-MICROSHIFT FD-M462 front derailleur
-SHIMANO Altus rear derailleur
-SHIMANO Acera shifters with speed indicators
-MICROSHIFT H092 9-cog 11 to 36 tooth cassette
-KMC X9 chain

HANDLEBARS, STEM, GRIPS

The adjustable stem brings the ST 540 controls to your hands. The all-aluminium Rockrider stem is 70 mm (size S), 80 mm (size M/L), or 90 mm (size XL) and can be raised to 5 adjustment intervals: + 0mm, + 7.5mm, + 15mm, + 22.5mm, + 30mm.

In detail: – 720mm oversize Rockrider Sport aluminium handlebar
– Rockrider Sport “soft touch” ergonomic grips for good grip and a comfortable feel.

Saddle

Our teams designed and created an exclusive ROCKRIDER ERGOFIT saddle. Designed for all hip widths, its hammock shape is very comfortable for long, athletic rides. The Flex 27.2mm diameter aluminium seatpost also contributes to its increased level of comfort.

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

HYDRAULIC DISC BRAKES

No matter what conditions you ride in (dry/wet), the Rockrider by Tektro 160mm double hydraulic disc brakes will come through for you, even in the mud.
Hydraulic braking adds more power and progressive braking and requires less powerful use of the brake levers.
The aluminium brake levers are easy to grip and precise.

27.5″ WHEELS WITH DOUBLE-WALLED RIMS AND ALL-CONDITION TYRES

The aluminium wheels are effective and sturdy: 27.5″ diameter and double-walled rims. Their diameter is the perfect balance of comfort and performance. With their 28 spokes, they are lightweight, stiff, and durable.
The wide, ROCKRIDER ALL CONDITIONS (60 TPI) 27.5″ x 2.1 tyres have side knobs designed for riding on all types of terrain (dry, wet, etc.).
Tubeless Ready 23 mm rims: SCHRADER valves, TUBELESS rim tape, TUBELESS tyres, and puncture-proof liquid to be added.

Platform pedals

The ST 540 comes with Rockrider Flat platform pedals with a wider pedalling surface and more pronounced dots for better grip on the pedal.

EASILY TRANSPORT AND STORE YOUR MOUNTAIN BIKE

We added a quick release system for easily removing/reattaching the front wheel.
Our advice: a bike rack is an easy way to transport your mountain bike without dirtying your car.

Accessories

Your ST 540 mountain bike is fitted with a bell, lights, wheel reflectors and pedals.

The frame is compatible with:
-500 chainstay stand (ref. 8302792)
-100 bottle cage (ref. 8049106) and 500 bottle cage (ref. 8358133)
-Mountain bike mudguard set (ref. 8385291)
-100 saddle bag (ref. 8347394) and 500 saddle bag (ref. 8354448)
-500 pannier rack (ref. 8364376)
-100 frame child seat (ref. 8486913 and 8487125), whatever the size

COMFORT & SAFETY

Your bike’s fittings (chain, derailleur, brakes, etc.) will adjust over time. Take advantage of a free servicing within 6 months after purchase. Our technicians will carry out a 13-point inspection of your bike. Just come to your nearest Decathlon workshop with your Decathlon card and/or receipt.