B'twin Rockrider 27.5" ST 100 Alloy Hardtail Mountain Bike

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The B'TWIN Rockrider 27.5" ST 100 Mountain Bike features an aluminium hardtail frame with front suspension, 21 speed Microshift groupset (3 x 7), V brakes & 27.5" wheels, weighing 15.3kg and is finished in grey & yellow.

B'Twin Rockrider 27.5" ST 100 HT MTB

  • B'TWIN Men's Alloy Hardtail MTB Frame with Front Suspension
  • 27.5" Wheels (V Brakes)
  • 21 Speed (Microshift Groupset - 3 x 7)
  • Available in XS, S, M, L & XL in Grey & Yellow.
  • Weighs 15.3kg

The Rockrider ST 100 - worth the money?

The Rockrider ST 100 Mountain Bike is a low cost hardtail MTB designed for the smallest of budgets. Featuring a 27.5" wheelset, alloy frame and 80mm of unbranded front suspension, it's a rideable hardtail mountain bike for those starting out.

In terms of value for money, it's not a terrible specification, but unfortunately (and somewhat understandably given the low price tag) doesn't include disc brakes, nor even disc mounts should you wish to upgrade at a later date.

The ST 100 has 21 gears from a mainly Microshift groupset (Shimano provide the 7 speed cassette) including a triple chainset to help get you up the steeper ascents and is available in bright yellow or understated grey colour schemes.

Shifting is via old school gripshifter style controls mounted on a pretty narrow 620mm set of steel handlebars - we'd recommend upgrading these for wider alloy models to save weight and gain control.

In short, it's not a bad starter bike for newcomers in terms of value for money, but will weigh a substantial amount (between 15.3kg to 15.8kg - 33.7lbs to 34.4lbs - depending on frame size) and in time you may wish to upgrade to a bike with disc brakes and wider bars. If this is the case then the Rockrider ST 120 costs slightly extra, but is more future proof for upgrades and thus should last you longer.

This 27.5" mountain bike is designed for your first mountain bike rides in dry weather for up to 11/2 hours.

Effective? Strong? Both please! Easily get through your first obstacles: lightweight aluminium frame and 27.5'' tyres on double-walled rims (26" in XS).

Cycling comfort: Enjoy touring: raised position, 80 mm suspension, hammock saddle, FLEX seat post.

Robustness: An ultra-strong MTB: double-walled rims, welded saddle, derailleur guard.

Efficiency: Light frame, 21 speeds, 27.5" wheels (XS 26"), tyres with low rolling resistance.

Directional control: Control your steering: V-Brake pads, tyres with side lugs. The ST 100 mountain bike frame is UNISEX.

The ST 100 mountain bike exists with the same frame in a WOMEN'S version: adapted seat, narrower handlebars, shorter stem, fork with a more flexible spring, and brake levers that are closer to the handlebars. As a WOMAN, if you choose the MEN'S model, we recommend purchasing the WOMEN'S SPORT 500 saddle which is adapted to women's body types.

A LIGHTWEIGHT, COMFORTABLE, FUN FRAME: It isn't always easy to get the right position on a mountain bike.

Our designers have created an entirely new frame that is easy to step over. The 100% aluminium CGF frame (Comfort Geometry Frame) is both comfortable and easy to handle. The slope angle has been designed to keep your back straighter whilst the rear has been shortened to ensure the bike is very agile when turning.

FRONT SUSPENSION: The 80 mm front suspension helps you overcome your first obstacles on slightly uneven trails with no worries. Its mechanical spring is a stamp of reliability. And the fork is particularly easy to maintain.

To adjust the stiffness? It's very easy using a single dial.

REAR SUSPENSION: NONE: This mountain bike has no rear suspension.

It is a "hardtail" mountain bike: perfect for beginners launching themselves into their first mountain bike touring rides.

Compared to a full suspension mountain bike (with rear suspension), the advantages are clear: the mountain bike is lighter; you expend less energy pedaling on flat ground.

DERAILLEUR & DRIVETRAIN: 3 x 7 speed chainwheels, 21 speeds total! 2 easy-to-use grip shifters on the handlebars.

Left (chainrings): control ascents/descents.

Right (speeds): more precise control over your pedalling. In detail:. Triple-chainring chainset (22/32/42 teeth) + anti-grease protection.

Microshift FD-M20 front derailleur. Microshift RD-M25 rear derailleur. Microshift MS25 grip shifters with speed indicators.

Shimano TZ500 7 cog cassette, 14 to 28 teeth.

Large, solid KMC Z51 chain HANDLEBARS, STEM, GRIPS: With a stem that tilts 10 degrees upwards, the riding position of the ST 100 is raised, accessible, and comfortable. In detail:.

90mm (in sizes XS and S) or 110mm (in sizes M, L and XL) aluminium stem with an angle of 10 degrees for maximum comfort. 620mm-wide steel handlebar, for stability and control. "Soft touch" grips for a firm yet soft and pleasant grasp.

SADDLE: The saddle of the ST 100 is welded to prevent any movement of the saddle. And because your comfort is our next priority after safety, we've added an exclusive wider Ergofit saddle with a hammock shape. Easily adjust the height of your saddle with the Flex steel seat post, either 350mm or 400mm long (according to the bike size).

Its reduced diameter of 27.2mm provides your seat with natural flexibility, 30% more than a standard solution.

V-BRAKES WITH PADS: Two V-Brakes for effective braking. These brakes are composed of callipers that exert more or less pressure on the rim to slow or stop the rotation of the wheels.

Thanks to the special design of the ST 100's aluminium brake levers, you only need two fingers to brake.

27.5" WHEELS (26" in XS) & TYRES FOR DRY TERRAIN: The wheels of the ST 100 are tolerant and robust, with 27.5" double-walled 28-spoke rims (26" for the XS size).

Slow down without worrying about obstacles: small rocks, cracks, holes and bumps! Because your first rides will be on dry ground, this mountain bike is equipped with DRY 27.5 x 2.0 tyres.

Their performance has been optimised thanks to a faster central section, while their side lugs offer excellent traction in turns.

PLATFORM PEDALS: The Rockrider ST 100 mountain bike is supplied with hard resin platform mountain bike pedals for added lightness and safety. If your foot slides on the pedal, there's less risk of injury.

TRANSPORT & STORAGE: We added a quick release system for easily removing/reattaching the front wheel. There is a nut at the back to secure the bike and limit the risk of theft. You will need a spanner to remove the rear wheel.

Tip: a bike rack is an easy way to transport your mountain bike without dirtying your car.

ACCESSORIES: Your ST 100 mountain bike comes with a derailleur guard, chainring guard (to prevent your clothes from getting dirty), bell, lights, wheel reflectors, and pedals.

Weight: XS - 140-154cm : 15.3 kg.

S - 155-164cm : 15.4 kg.m - 165-174cm : 15.5 kg.

L - 175-184cm : 15.6 kg.

XL - 185-200cm : 15.8 kg.

.. more details.

Rockrider 27.5" ST 100 Mountain Bike Specification

Bike TypeMountain Bikes
Frame Material
Frame Type
Fork Type
Brakes Type
Number of Gears
Wheel Diameter
Size, , , ,
Designed for
Lowest Price£229.99

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How about some of these Men's Hardtail MTB deals instead?!

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Not convinced this is the right MTB for you? Check out my Mountain Bike page, full of my latest sale bikes - from 26" Alloy Hardtails to 29" Carbon Full Suspension Bikes, and everything inbetween - all searchable by size. Or for those of you who prefer tarmac, view my road bikes listings instead.

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