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Rockrider AM Fifty_S 12-Speed Full Suspension All-Mountain Bike 27.5" - 29"

Sale price: $2,499.00 Regular price:

This version of our AM Fifty_S full-suspension mountain bike opens the door to official routes and technical trails, making it the most versatile bike in the all-mountain range.

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Sale price: $2,499.00 Regular price:

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About this item:

  • The full suspension aluminum bike with perfect travel to conquer your favorite trails
  • Rockshox Recon Silver 140 mm fork, Manitou Radium 140 mm shock
  • 12 speed Sram SX 12spd drivetrain/ Tubeless ready wheels
  • Hutchinson Toro tires: 27.5 x 2.25 in size S and M, and 29 x 2.10 in L and XL
  • Lifetime Warranty: frame, stem, and handlebars guaranteed for life
Model: 8787134

Product Videos

Product Features

A photo of the Rockrider AM Fifty_S 12-Speed Full Suspension All-Mountain Bike 27.5" - 29" in use
A photo of the Rockrider AM Fifty_S 12-Speed Full Suspension All-Mountain Bike 27.5" - 29" in use

Rockrider AM Fifty_S 12-Speed Full Suspension All-Mountain Bike 27.5" - 29" | This AM Fifty_S mountain bike has been designed for use on landscaped terrain and technical trails.

This version of our AM Fifty_S full-suspension mountain bike opens the door to official routes and technical trails, making it the most versatile bike in the all-mountain range.

Directional control

Steering control: 67° head angle, low bottom bracket, dropper seat post

Shock absorption

Rockshox Recon Silver 140 mm fork, Manitou Radium 140 mm shock

Braking power

SRAM Level brakes with dual-piston calipers and 180 mm / 160 mm discs.


Hutchinson Toro tires: 27.5 x 2.25 in size S and M, and 29 x 2.10 in L and XL

Questions & Answers

Product Customer Reviews

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256 Reviews
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Rockrider AM Fifty_S 12-Speed Full Suspension All-Mountain Bike 27.5
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Very good, well-equipped mountain bike

I bought this bike in size M equipped with a 27.5" wheel to replace my RR 9.1 26". The evolution of the geometry and the size of the wheels greatly contribute to the behavior of the bike, particularly in terms of dimensions. I also enjoy the descents a lot. Personally I bought it as a basic version for the upgrade later with a better fork and shock absorber. The small torque wrench provided is well thought out. Only small downsides: - no adjustment instructions for the shock absorber fitted as standard. - the screws that hold the shock absorber are rusty after 18 months of use, which is average for the perceived quality (I store my bike dry in my garage)



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The bike has a very strange set-up, it is heavy

It has a strange geometry, the front wheel loses its grip easily, the brakes are very "meh" after a few laps, if you press the brake hard for a few seconds, it brakes but does not offer a feeling of security, I hope that after I start grinding the pads again, it will recover . The tires that came with the bike were very heavy and besides that you said you were riding on cinder blocks on any terrain and they were very noisy. The fork does not work anywhere near as well as a rockshocks tora tk 29 on the spring I am extremely disappointed with the way it actually works it makes strange noises and works hard and the rebound is very noisy you say it doesn't have enough oil or something incorrectly mounted. The sheet is very small and is not at all suitable for a flat bike on the small sprocket, you cannot go over 17 km per hour no matter how hard you try with a cadence of over 100 and you have no chance of exceeding this speed. When climbing, it is absolutely horrible, regardless of whether you pedal on the saddle or in the drop, you feel the strange geometry instantly. The tubeless redy rim base on the rear wheel was mounted badly and I had to replace it to be able to fit tubeless tires. I went to the Decathlon Berceni store and there you don't have service in the true sense of the word, unfortunately the people there don't know and more importantly they don't have the tools to service brakes or forks or center a wheel. Honestly, I am very disappointed with the choices made by decathlon. When you opened the first military store, I was part of the team that actually set up the store and I was part of that team for almost 2 years in the bicycle and service district. And I had all the tools and all the necessary knowledge to do everything related to servicing a bike regardless of its range or complexity. The chosen direction is not correct, it is 100% wrong.

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AM 50 S


barely 400 km and broken bike

I bought Rockrider Am 50 S almost two years ago and I have barely used it, some short outings of a maximum of 20 km, now I have been riding on the roads of Tremp and Pobla de Segur for three weeks with a total of about 400 km accumulated doing outings of 20 At 30 km and suddenly I find the rear shock absorber loose with a screw hanging and the two frame supports bent. Impossible to reposition. I still can't explain what could have happened. The bike is now in the Barcelona workshops for review. What bothered me the most is that the guy at the Lleida workshop told me that this had happened to me due to poor maintenance, blaming me. The bike has not a single fall and is new, all the parts are original and look new. Now I don't trust this bike anymore. The luck is that I spend it on the flat and not going down paths.

Lack of documentation

Lack of documentation

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I recommend

I recommend it with a clear conscience, the L frame is perfect for a person 178 cm tall. The bike is comfortable and handles confidently. Bought on sale, which puts it in the light that this is the best possible new full-suspension bike at this price.

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"Zero inspection" is a mockery - the bike is inoperable

The model may have potential, but it is difficult to evaluate the bike itself positively when you get a defective one from the very beginning. The worst thing is that most of it concerns elements that are supposedly checked before the bike is handed over to the customer. But in order: 1. Sram SX definitely does not cope - gear changes take place with a delay - even several seconds. And I don't mean aggressive driving over bumps, but an ordinary forest road 2. several gears do not engage at all - after the next click, the chain jumps by 2 sprockets - AND THIS SHOULD BE CATCHED BY A SERVICE PERSON 3. In my case, the 2 smallest gears - they do not engage in general - AND THIS SHOULD BE CATCHED BY A SERVICE PERSON 4. The brake pads are rubbing against the discs - they are not aligned. Yes, I can adjust it on my own - BUT IT SHOULD BE CATCHED BY A SERVICE PERSON. New purchase - and as soon as "good morning" I have to return it to the queue and wait a dozen or so days for you to kindly correct what you botched during the sale??? I also wonder who will compensate me for the time and money I lost in bringing my bike to the service center. Very weak. I have been riding for a long time, but I have never experienced such poplin at zero inspection.

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handy bike, playful, very…

easy to handle, playful bike, very good value for money

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The money changer is two pennies

After I paid that much, it also comes with the changer out of order and after I adjust it, it goes out of order again, otherwise everything is good but the changer is a disaster

The pedals were not…

The pedals were not tight at all, the derailleur was not adjusted, the last 2 gears did not shift, I had to loosen the derailleur cable for the gears to shift properly.

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Great bike!

Perfect solution for 30/80 driving (asphalt - mountains/forest). I bought it in size L with 29 cm wheels. The bike doesn't put up any resistance, you don't have to fight it, it climbs well and can handle the mountains.

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Great value for money

Great value for money

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The transmission adjustment is not great and almost impossible to fine-tune, I then changed the chainring to 34 teeth. The rear brake whistles constantly when used (really loud), and in general is pleasant but lacks power during heavy braking (I weigh 60kg). The bike performs very well technically and only requires a good pair of tires to push the limits. I was afraid for the fork but with the original brake I can't reach the limits of its rigidity, the rear suspension does the job but the preload dial doesn't really change the feeling. In short, it's an incredible bike for beginners and a good base for experienced riders. You can easily make him lose 1kg for a few extra euros.

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finally a bike for my size 1m87 for 95 kg I can finally go into the forest to cross, descend on uneven terrain accelerated put pressure for starts on my pedals and my crankset without risking breaking a pedal, a crankset or the suspensions the two suspensions at the top front of 140 really comfortable even for the central quality price nothing to complain about the tubeless also is essential Great Decathlon product a mountain bike at the top city, forest, full assembly, quays of the Seine and near the road on bitumen on all types of terrain and even very uneven ones, thanks to the defense cycle manager Christophe for my speed adjustments, it goes well since October my purchase the speeds shifted poorly despite several visits to the repair workshop, but the adjustments do not were not optimal thanks to the team and Christophe

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Size Guide

Size Guide Visual

Additional Product Information


Bike frame: 100.0% Aluminium

Which is the right size?

Several sizes available: S: 5 ft1 Inch to 5 ft5 InchM: between 5 ft5 Inch and 5 ft9 InchL: between 5 ft9 Inch and 6 ftXL: between 6 ft1 Inch and 6 ft5 InchIf you are on the edge between 2 sizes: Choose the smaller size for easier handling and comfort (straighter back).Choose the larger size for easier pedaling with a more stretched-out position (position more suited to higher performance).

How this mtb was designed

Entirely designed and developed in France at the B'Twin Village (Lille), this mountain bike is the fruit of the work of a team of experts and passionate all-mountain bikers who test the products in the Vosges and the Alps. The Rockrider team designed and tested this AM Fifty_S All-Mountain bike together with their MTB testers. The AM Fifty_S is assembled at our own factory in Lille, just steps away from the bike design team.


The Rockrider All Mountain frame offers 140 mm of travel on the rear wheel.Its geometry has been optimized for steering: 67° head angle, 15 mm bottom bracket under the wheel axle.Made of 6061 and 6013 aluminum.Lifetime warranty on the Switch & Ride frame: compatible with 27.5Inch and 29Inch wheels. 148 mm x 12 mm Boost rear axle.Press Fit 92 bottom bracket.31.6 mm diameter seat post.Compatible with a bottle cage.Weight in size S: 6 lbs.

Front suspension

Rockshox Recon fork with 140 mm travel.Compatible with 27.5 Inch and 29 Inch wheels and tires up to 2.8 Inch wide. It uses the boost standard for maximum control, fun, and comfort.The Recon fork has been designed with a tried-and-tested Motion Control cartridge, with low speed compression adjustment to lockout and external rebound adjustment.Fast Black steel finish on the dampers.Solo Air spring that takes just seconds to adjust, for a smooth, predictable ride.

Rear suspension

Manitou Radium 140 mm rear shock designed specifically for the Rockrider AM Fifty_S mountain bike.Adjustable to reduce bobbing during long climbs on faster terrain.


SRAM SX 12S 30 x 11-50 drivetrainSingle chainring for less weight, more precision, faster gear changes, and more durability.Rack: 30 teeth, easily replaceable (32 or 34-tooth chainring, available) without changing the chain. Cassette: SRAM Eagle in 11-50 (11-13-15-17-19-22-25-28-32-36-42-50). The 50-tooth sprocket guarantees good gear reduction to help you climb the steepest slopes.

Riding position

Control your steering and stay precise.RockRider Comp Flat handlebars, 740 mm wide for greater stability. 60 mm stem for a position that fts more suited to fast terrain Semi-integrated headset with sealed bearings. Lightweight RockRider 900 Inchlock on Inch grips (attached to the handlebar with a screw-on system).


SRAM Level brakes: The dual-piston brake caliper performs perfectly for all-mountain beginners and is a safe bet. 180 mm front disc, 160 mm rear disc.

Saddle and seat post

The RockRider XC/AM saddle has an Ergofit system for greater comfort while pedaling.The height of the dropper seat post can be adjusted using the control on the bike's handlebar: 120 mm of travel in size S/M and 150 mm in L/XL. The ability to lower the saddle in a second with a single press of the thumb is a real advantage in all-mountain biking. Feel at ease (and relaxed!) in your seating position on the bike during technical descents.

Product testing

Ask your local Decathlon store about testing before purchase.

Storage instructions

We recommend storing your mountain bike in a cool, dry place, away from corrosive products and salty air.


Lifetime (frame, stem, handlebar). Details on our website. Availability of spare parts: 2 years.



Ca warning

California Prop65 WARNING: This product can expose you to chemicals including Lead, which is known by the State of California to cause cancer. For more information, go to


Size Guide Visual

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