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27.5 Inch Electric Mountain Bike E-ST 520 - Grey/Yellow

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Sale price: QAR 9,605.00 QAR 9,605.00

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This electric mountain bike has been designed and developed by us to best suit mountain-bike rides on hilly and rolling terrain.

With the E-ST 520 electric mountain bike, you can tackle any climb. With the help of its built-in motor (70 Nm torque), even the most difficult of hills will be manageable.

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Sale price: QAR 9,605.00 QAR 9,605.00

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Product Features

A photo of the 27.5 Inch Electric Mountain Bike E-ST 520 - Grey/Yellow in use


Head for the summit powered by a 250W motor with 70Nm torque


Ride an average of 2.5 hours at a sporty pace thanks to the 420Wh battery.

Smooth pedalling

The built-in motor automatically assists you when needed. Perfect for MTBing.

Cycling comfort

Enjoy: raised position, 120 mm suspension, wide tyres, hammock Ergofit saddle.

Directional control

Control your trajectory: hydraulic fork and brakes, tyres and a wide handlebar.

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Product Reviews

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768 reviews

27.5 Inch Electric Mountain Bike E-ST 520 - Grey/Yellow
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Superb value for money

Like most people making this kind of investment I spent a lot of time researching this purchase. Got to say I am delighted with the choice I made, I think the build quality at this price point is superb and the smile factor really high. I did 20 miles on it yesterday and still had 3 bars left on the charge. You only need highest power mode for the very steepest climbs and 1 and 2 fine for the rest. You still get a work out but if you aren't that fit or looking for a gradual way back in its just perfect. Its fine on the road and canal paths and more than capable in the forest, cant recommend highly enough, fab!

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Thank you for your feedback Simon.

We really appreciate you taking the time to do this.

Have a great day and happy cycling!


Sports Advisor (Customer Service)

Decathlon Wednesbury

Decathlon UK Limited. Company number: 03140144. VAT number: GB679262296.

Registered office: 9 Maritime Street, London, SE16 7FU.


Very pleased with it especially the staff at Decathlon huyton who were very helpful and courteous

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Great bike for the price

The EST 520 is great. I do feel like I'd much more enjoy the EST 900 but I couldn't return the 520 without a loss. It's great for commuting and going off road. The forks are lacking which was my reason for wanting to swap. If you don't ride down stairs or rocks it's very sound for the price. Battery lasts a decent amount too.

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Good bike, best one I could afford, definitely worth the investment. Helps me get up the hills to work and when about and about in my leisure time, just with they did them in nicer colours

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Good product we'll impressed withve bick

Good product we'll impressed with the bick

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So where can I get a spare battery

Need a spare battery

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A lot of bike for your money

I bought this bike to commute to work on last year, and for the occasional set of trails. I’ve found it pretty easy to live with. The battery charges quite quickly, and gives me more than 50km range, using a mixture of the highest assistance level and the medium assistance level. Charging is straightforward from a normal plug socket (but I did have to buy an adaptor, as you get a European two pin plug in the box.) Repairing punctures is straightforward, getting the tyre off the rim requires some strength, but a good pair of tyre levers helps. I changed the tyres for something a bit more road friendly and efficient, but put the chunky Mtb tyres back on for trails and exploring. Riding where I live (which is hilly) is made a lot easier by the electric motor. Hills become easy and you can do a lot more distance in a day. I probably wouldn’t have become as familiar with my local area as if I hadn’t got this bike - it made exploring fun and easy.

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Very good product and quality!

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I can't tell you how much I like this bike

I brought this bike as an overweight man looking to get some exercise with some assistance and also to be able to travel further than I would on a regular bike. I've not cycled for 10-15 years until I brought it and I can't tell you how good it is - I feel 12 again. For the cost I'm amazed at how easy to use and how easy/comfy to ride and cheap to maintain it is. I'm so glad I have it. I use it 4-5 times a week, and regularly do a 22k commute on it and also fully drain the battery for ~3 hours on day trips. It's wicked, I just don't know why I waited so long.

Amazing Bike

I've had this bike for almost a year now, an its been amazing. I use it every day for cycling to work. It handles step hills easily. Plus the ride is self is so comfortable. Would definitely recommend

Great piece of kit!

What a great bike this is. I had been looking at so many ebikes my eyes were beginning to bleed! This is a well specced bike and great value for money. It has managed to take me everywhere I have pointed it at and not grumbled at all. In just 2 weeks I have done over 150 miles of off-road adventuring in and around the Surrey hills. It has coped well with some really gnarly tracks both uphill and descents. My only gripe was that on delivery the box was opened and it wasn’t for my secured in the box, and that assembly required disconnecting the front brake calliper to move the handlebars to the correct side of the fork but even a novice like me managed this. Thanks decathlon a great bike and wouldn’t hesitate to buy again. So pleased with my purchase!

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Hello Beetz

Thank you for your comment. We are happy to be able to satisfy your needs because it's our ambition. We would like to advice you if you have a chance next time to place a Click and Collect order. Like this the mechanics in the local workshop will do a safety check before to provide the bike to you and the bike will be 100% ready to ride.


Fast delivery

Great service fast delivery and bikes as described

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Rockrider E Bike

Love love love this bike! After struggling to keep up with my super fit partner I found myself effortlessly cycling up the steep hill with a big grin on my face and reached the pub 10 minutes before he did! He was so impressed by my new found speed he purchased an e bike the following week

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Electric power

Although I felt the price was high this is a fantastic bike the power delivery is seem less and gives just the right level of assistance in each mode, the brakes are brilliant wheels and tyres just right and as everyone has commented the bike looks great

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Fantastic bike I’m well pleased with it

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Additional Product informations



  • 100% Aluminium 6061

Which is the right size?

Several sizes available:S: between 1.50m and 1.64mM: between 1.65 m and 1.74 mL: between 1.75 m and 1.84 mXL: between 1.85 m and 2.00 mIf 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).

Is electric mtb a sport?

You have to pedal to go forward!The electric assistance boosts your pedalling by 320%, helping you ride over obstacles. You'll get to enjoy longer MTB rides.The motor stops providing electrical assistance when you stop pedalling.The walking mode offsets the mountain bike's weight when you need to walk your bike.

A word from the team

Our team of mountain bike enthusiasts created this E-ST 520 electric mountain bike entirely at our B'Twin Village in Lille, France.We designed and tested the E-ST 520 MTB by involving MTB riders at every stage of the project.

Sturdy, playful frame

The frame of the Rockrider E-ST 520 electric MTB is made of 6061 aluminium with hydroformed tubes. Why? The battery sits snugly on the frame to improve the robustness of this electric mountain bike.The forged aluminium parts make it compatible with the new 27.5"+ tyre format (wider than the 27.5") in the rear, while remaining easy to manoeuvre. We've kept a frame geometry with short bases for easier steering.

Motor with 70nm torque

The BROSE T Aluminium central motor is specially designed for mountain biking:- 70 Nm torque to handle large obstacles and steep gradients- metal housing for maximum durability- belt for an ultra-quiet motor- sealed bearings to hold up to tough environments while mountain biking

Lg or samsung battery cells

Our battery is equipped with battery cells from LG or Samsung, (LGC-MG1 or SDI), which are known for their high level of reliability and safety.Our battery supplier sources its minerals responsibly and sustainably, and is part of the "Responsible Minerals Initiative".

Battery lock

Our Rockrider mountain bike team has designed a battery that locks in place with a simple lever. Child's play!This locking system prevents the battery vibrating when riding on rough terrain.There is also a lock in case you want to stop your battery getting stolen. For example, if you park your bike in the street.

Control screen

A discreet LCD control screen. It is located just to the side of your left grip, so you can choose between the 3 assistance modes without letting go of the handlebars: (Deactivated), Economy, Standard, and Boost.You'll also find a host of useful information:-Stopwatch-Current speed-Average speed-Maximum speed-Distance covered-Total distance-Battery level-Remaining battery range (in km)-Active assistance mode-Reset

3 assistance modes

Mode 0 - DeactivatedThe battery is not used.Mode 1 - Economy +60%:Extend your rides while conserving battery life. Ideal when you want a little push on small gradients.Mode 2 - Standard +120%:This is the most versatile mode. Climb any slope without getting too tired and without using too much power.Mode 3 - Boost +320%

Rockshox front suspension

Ride over obstacles (roots, pebbles, stones, etc.) easily thanks to the Rockshox XC30 hydraulic fork with 120 mm of travel.This fork has:- A coil spring for maximum sensitivity and reliability - a lockout and preload adjustment for better control, depending on the terrain

Single chainring drivetrain

The E-ST520 electric bike is equipped with a single chainring and ChainFlow 3D anti-slip technology to prevent the chain from derailing.A single shifter on the right handlebar makes it easy to shift between the 9 speeds.In detail:-Chainflow & Anti-derailment single chainring with 34 teeth-Microshift Advent 9-speed rear derailleur with long cage-Microshift Advent right shifter-Microshift H093 9-speed cassette (11 to 42 teeth)-KMC E9 Sport electric bike specific chain

Wide 27.5" double-walled rims

These wheels were specially designed for this mountain bike:- 23 mm rims (width between brackets), 28 spokes at the front and 32 spokes at the rear, for greater durability and good grip with wide tyres (up to 2.5").- BOOST thru rear axle (12x148) for greater durability- Aluminium hubs with sealed bearings- TUBELESS READY rims: you will need TUBELESS tyres, specific Presta valves, and puncture sealant.

Hutchinson tyres

In order for you to feel safe on any terrain, and for traction suited to your motor, the E-ST520 electric MTB is equipped with Hutchinson Cougar 27.5" tyres with a 2.4" cross-section. Our test riders particularly liked these tyres for their grip on the ground. Mounted on wide rims, these tyres provide great grip, traction, and comfort on any terrain.

Hydraulic disc brakes

Regardless of the conditions you ride in (dry/wet/muddy), the hydraulic Tektro TKD88 disc brakes at the front and rear provide powerful and progressive braking. Oversized 180mm diameter discs provide even more power.

Handlebars, stem, grips

The adjustable stem brings the E-ST 520 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.


Since your mountain bike rides will get longer and longer, it is important to have a suitable seat. Our teams have designed the exclusive Rockrider Ergofit Evo saddle. It fits all hip sizes and has a curved shape that is particularly good for sport trail rides.The 31.6 mm aluminium seat post ensures compatibility with most adjustable and suspended seat posts on the market.

Platform pedals

The bike comes with 520 GRIP MTB platform pedals (ref. 8487130) with a wider pedalling surface and more pronounced dots for better grip on the pedal.However, if you are looking for improved performance when pedalling and better control of the bike when cycling, we recommend replacing them with clipless pedals with platforms or wide aluminium platform pedals.


Your E-ST520 mountain bike is fitted with a bell, lights, wheel reflectors and pedals.The frame is compatible with:- front and rear mudguards- stand- bottle cage (on the horizontal tube)- saddle pouch- rear pannier rack (fixed onto the seat stays or special mounts for wide bikes, 148 mm gap for the rear wheel & 2.8" fat tire)- child seat...

Our advice for your first rides

Tip no.1When mountain biking, there is always the risk of a fall: don't forget to wear a helmet.Tip no. 2A puncture could happen at any time, so always remember to take a repair kit and a 6 mm Allen key for removing your wheels.Tip no.3If you don't want to stop to drink, bring water in a bottle or water bladder to access it while riding.

Legal disclaimer

To ensure components last longer, we recommend a maximum load of 120 kg (rider and MTB included).

Care advice

Leave your battery on the bike when washing using a hose. This will protect the connectors from rusting.

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