REF: 8607197, 8654920, 8654913, 8580822, 8655219


This electric mountain bike (E-MTB) is designed for all terrain rides with a gradient (rolling hills and moderate mountains).

It's perfectly suited for improving and discovering new horizons in mountain biking.

First use

Inflating the originally installed tyres (tubetype)

Having the right tyre pressure is particularly important on an electric bike.
The wheels have a lot of weight on them because of the combination of the motor and bike.

On the original inner tube assembly (Tubetype):

To reduce the risk of punctures and ensure your bike can achieve its maximum range, we recommend you inflate your tyres to a pressure of between 1.0 and 1.8 bar.

If you're looking for more traction and comfort, you can lower the pressure. If you're looking for more battery life and pedalling performance, you can inflate the tyre a bit more.

Take care not to exceed the maximum AND minimum pressures displayed on the sidewall of your tyre.

An under-pressurised tyre can cause pinching of the inner tube and can damage the rims when riding over obstacles, while an over-pressurised tyre can explode the inner tube, the tyre, or deform the rim over the long term.

A well-inflated tyre is essential for your sport. So remember to frequently check your tyre pressure.


Inflating the tyres in a tubeless assembly

TUBELESS is a great way of getting the most out of your tyres. The pressure is lower (by about half a bar) than with tube-type tyres. As it's less inflated, the tyre's "carcass" will be able to come into contact with the floor. And it won't be stopped by the inner tube.

With a tubeless set-up, the aim is to lower the pressure to get the most out of the tyre without the rim touching the floor as you go over obstacles.

Make sure not to inflate your tubeless tyres above 3 bars, as your aluminium rims could get damaged.

A well-inflated tyre is essential for your sport. So remember to frequently check your tyre pressure.

NB: Unlike your rims, your HUTCHINSON Cougar tyres are not Tubeless Ready.

First use
Adjusting your fork

Your SR SUNTOUR XCM fork needs to be set up according to your riding style, the terrain and your preferences, but most importantly according to your weight.

There is only one type of adjustment on your fork: the preload

The preload determines the hardness of your fork. To adjust it, turn the wheel at the left of your fork. Clockwise will tighten the spring and make the fork harder. Counter-clockwise will loosen it and make the fork softer. The wheel on the right is used for locking the suspension, which is useful when accelerating on more rolling terrain.

The fork can be locked to optimise your bike's performance on smoother areas. The wheel is located above the crown of your fork on the right side.

Bedding in your brakes

When your bike leaves the shop with its shiny new brake pads and discs, their braking power is weak. A sharp prolonged braking action (for example, during a descent) with brakes that have never before been used can cause the pads to overheat and to "glaze over".

To ensure that your brakes perform, we recommend that you bed them in. This takes about 10 gentle braking actions per brake. For each braking action, apply a single brake to slow the bike down from about 25 km/h to 5 km/h without fully blocking the wheel. Repeat with the other brake.

If you can see a thin, shiny layer on the top of your brake pads, this probably means that they're glazed. To avoid having to throw them away, you can deglaze them by sanding them lightly with some relatively fine sandpaper (P120). Remember to wear gloves and a mask when sanding your brake pads. Then simply remount your brake pads and bed them in again.

Adjusting the height of your handlebars

Your handlebar is set to the most raised position, which is the most comfortable position for riding.

For improved aerodynamics and more efficient pedalling, you can lower your handlebar so that your body leans forward and adopts a more racing-like position.

Follow the steps in this video to move the headset spacers below the stem and lower the handlebars on your bike.


Aligning your handlebar

Proper handlebar alignment will prevent arm and shoulder pain as well as improving your mountain biking experience. Check out this video to learn how to align your handlebars.


Positioning your brake levers

Properly positioning your brake levers is important for safety and comfort on your bike. Check out this video to learn how to orient your brake levers.


Fitting your gps

Your mountain bike is compatible with a stem sensor mount (or Computer Stem). You can directly attach your sensor/GARMIN or SIGMA GPS.

NB: If you use spacers above your stem, the mount will not display correctly and you'll need to slightly "saw" the spacer with a Stanley knife. If your spacers are under the stem, the computer stem will fit perfectly.


Adjusting the height of your saddle

The correct saddle height will increase your comfort and performance on the bike. 

Stand next to your saddle. Tilt the quick-release lever to unlock it. Pull the saddle up or push it down to bring it level with your pelvis. Tilt the lever again to lock it. To make sure you get it right, take a look at our tutorial video.


Adjusting the tilt of your saddle

Adjusting the tilt of your saddle will improve your comfort and performance on the bike. Check out this video to learn how to adjust the tilt of your saddle.


Changing your pedals

Follow this video to learn how to replace your pedals. 

If you are choosing clipless pedals, practise clipping and unclipping your shoes in order to prepare for possible falls when riding. 


How to convert your wheels to tubeless

To reduce the risk of your inner tube being punctured or pinched, and to improve grip and comfort, you may want to consider making your mountain bike wheels tubeless.

Your wheels are Tubeless Ready, meaning that they already have a watertight rim strip. All you need is a pair of Tubeless Ready tyres, Tubeless valves (PRESTA) and liquid sealant (puncture protection). Remember to wear gloves and goggles to protect yourself in case you get a blowout.

To go tubeless, follow these steps:

1. Remove the wheel
2. Remove the tyre and inner tube from the wheel
3. Check that the rim tape is properly stuck on and that there aren't any bubbles or tears
4. Insert a tubeless valve through the rim hole (from inside the rim)
5. Add between 60 and 90 mL of anti-puncture liquid sealant (depending on the width of the tyre)
6. Fit your new TUBELESS READY tyre.
7. Inflate the wheel quickly to ensure that the tyre sticks to the rim.
Please note, never exceed 3 bars of pressure, or you risk exploding your tyre or damaging your rims.

If it seems too tricky, just visit your nearest Decathlon workshop and ask them to do it for you.


Operating the screen

The Stop/Start Button allows you to turn your screen on and off. Use the up ^ and down ˅ arrows to toggle between the different assistance modes:

Mode 0 - Deactivated
Mode 1 - Economy +60%
Mode 2 - Normal +120%
Mode 3 - Boost +280%

On each of the assistance modes other than Mode 0, a long press on the ^ button will activate the Pedestrian Mode, which helps you push your bike when on foot.

Your mountain bike doesn't have any lights, so the lights button won't do anything. But you should know that a long press on the ˅ button will turn it on or off.

Questions about your battery? 

How long does it take the battery to charge?

It takes three hours to charge the battery fully (from 0% to 100%).

Can you ride when your battery is flat?

It's an electric-assist bike. That means it's entirely possible to ride without this assistance.
However, you may well notice the additional weight of the assistance system.

Can you leave your charger connected to the battery even after it has finished charging?

To avoid any electrical hazards, we advise against leaving your bike/battery plugged into the mains for more than 24 hours.
When the battery is fully charged, the charger stops charging. The LED light on the charger turns green when the battery is charged.

Should you wait until your battery is completely flat before charging it?

No. Lithium-ion batteries have no memory effect. So they can be charged at any time.
We recommend charging your battery regularly to keep it working well.

Does the battery charge while cycling?

No, it doesn't have a dynamo. Some systems let you charge the battery as you ride or brake, but this doesn't generate much power.

What should you do with the battery when it wears out?

When your battery wears out, take it to your local Decathlon store, which will send it to a specialist facility to be recycled.

How should you store your battery?

You must store and charge your battery in a cool (between 10°C and 25°C), dry place, out of direct sunlight.
To avoid deep discharge, which may cause it to malfunction, do not put the battery away when less than 10% charged.
Ideally, charge it to 60% and remember to charge the battery (even if it's not being used) at least once a year to prevent deep discharge and loss of the battery's capacity.

Where can you buy a replacement battery?

You can buy a new battery from your local Decathlon workshop.
Contact your nearest workshop to check on availability and order times.

What is the lifetime of your battery?

The warranty on your battery is for 2 years or 500 cycles (1 cycle = 1 full charge + 1 full discharges, or two 50% charges + two 50% discharges). After those 500 cycles, we guarantee that the battery life will remain greater than 80% of that of a new battery. 


The right equipment in case of a hiccup

You need to have the right equipment with you when you're out and about on your mountain bike so that you can take care of a puncture, a broken chain or any other type of setback. Here's a selection of products that can get you out of a tight spot or two.

Have a problem?


Your battery won't charge

Make sure the charger you are using is an original one provided by Decathlon.
Connect the charger to the battery and to a mains socket.
Charger light is red: the battery is charging.
Charger light is green: the battery has finished charging.
Flashing charger light: the battery or charger has a problem.
A completely drained battery will take 6 hours to charge fully.

The charger's and the battery's connectors should be clean. There should be no dirt preventing contact between the battery and its charger.

Visit your Decathlon workshop to have them repaired.

One or more leds on your battery is/are flashing

THE LAST LED (furthest from the battery button) IS FLASHING.
Your battery is almost flat and needs to be charged. Plug your battery into the charger.

Your battery's voltage is low and it has not been charged for a long time. Plug it in as soon as possible to prevent full discharge and altered battery capacity.

Your battery has suffered an abnormal event which has caused it to malfunction. This malfunction may be temporary or permanent. Please visit a Decathlon workshop to have your battery and bike diagnosed.

LED battery
The screen is showing an error code

The screen may display an error code.

All defect codes are catalogued in the electrical user guides. Each code has an action to take to solve the problem.

If the problem continues or you are unable to perform the action, please visit one of our Decathlon workshops for a repair.

Low or reduced range

1. Make sure you are following the recommendations for using and storing your bike.
Your electric bike's range depends on a number of factors:
> THE LOAD ON THE BIKE: The range will be reduced if the bike is carrying too much weight.
> THE TYPE OF ROUTE: The range is reduced on climbs.
> THE TYRE PRESSURE: The battery will last longer with tyres that are correctly inflated.
> THE OUTDOOR TEMPERATURE: The range is reduced in colder weather (up to -50%).
> THE BOOST MODE USED: It is advisable to reduce the power assistance mode when the battery charge is low.

2. An old battery can have reduced performance.
The distance you can travel will therefore be reduced. Visit your Decathlon workshop to give your battery a check-up.


Your wheel is buckling after several rides

When you take your new bike out for a ride for the first time, a lot of parts can shift and fall into place.

One such part is the spokes, which can sometimes be heard creaking. This is caused by the residual twist from assembly.

Your wheels should not be buckled in any way at all. If they are, let your local Decathlon workshop know when you take your bike for its free service (six months after purchase) so that they can adjust it for you.

Your gears are not shifting properly

IMPORTANT: Before anything else, remember to remove the battery from the bike before repairing or maintaining the drive train.

There are several things you can do to ensure your rear gears shift properly:

1/ Check the position of the cable and housing:
1a. Housing ends that are out of position can obstruct the derailleur cable when it is being pulled and prevent the gears from shifting smoothly. If a housing end is out of position, push it back into place.

1b. If the derailleur is not moving even after you have engaged and disengaged the grip shifter, it probably means that the cable and its housing have seized up. You will need to have the cable and housing replaced.

You can bring your mountain bike into a Decathlon workshop to have the cable and housing replaced, or do it yourself by following this video. The only difference from the video is that there is a single housing that goes from the shifter to the derailleur, passing under the diagonal tube on the frame.

2. Check that the derailleur dropout isn't bent:
A bent hanger causes the derailleur to be out of alignment and therefore unable to function correctly. Stand behind your bike and check the alignment of the derailleur.

If the dropout is twisted or broken, take your bike to a DECATHLON workshop to have it replaced.

REMEMBER: You can have all the settings on your bike checked for free in the first six months following the date of purchase.

NB: If you regularly ride your MTB in wet or muddy conditions, or if you regularly wash your bike with lots of water, then your cables and cable housing will need to be replaced more frequently. Washing your bike using a high pressure hose is highly discouraged as it can push dirt and dust into the cable housing.

Lost key

If you have lost both keys to your bike, please visit a Decathlon workshop to have the lock on the bike changed. You'll be given two new keys to go with the lock.

Locking your ST900
Your chain is coming off (to be completed)

is the screed lockout activated
adjusting the chain guide 

Maintaining your mountain bike

Servicing your bike will keep all of its parts working for as long as possible and ensure you have the most fun when riding. Aside from the aesthetic aspect of having a clean bike, failing to service it can lead to problems, and problems lead to accidents: jammed cables, rust, leaks, premature wear, etc.

Good maintenance is good for your performances, while your bike's parts will also last longer, which means a lower environmental impact.

As soon as you start using the bike, some components will move slightly.
This is why we offer a free tune-up of your mountain bike within six months of purchase.

How to clean your electric mountain bike

To clean your bike properly, you'll need some bike cleaner, a sponge and a brush.

Rinse off the bike with a hose and apply the bike cleaner. Next, use the sponge and brush to work the cleaner in. It's essential to give the bike cleaner some time to act before rinsing the bike off.
When hosing the bike off, make sure you do so from a few steps away so as not to damage the mechanical components.
Lastly, dry your bike using a soft, clean cloth.

To wash your electric mountain bike, it is important to leave the battery on the bike. This will protect the leads from water!
Do not use a pressure washer as water could get into the ball bearings and permanently damage the electrical components.

Correctly storing your electric mountain bike

It is essential to properly store your mountain bike to improve its lifespan, particularly if it is an electrical assistance bike.

After your ride, we recommend:
> Clean off any mud and sand to prevent your bike from rusting.
> Dry and lubricate your drive train (being sure not to get any on the brakes) to protect it from rust and corrosion.
> Store your mountain bike in a cool dry place.

For winter storage, we have a few other tips to add:
> Put the derailleur on the small cog to release the tension on the cables.
> Ideally, charge the battery to 60%.
> You can coat your bike in a thin layer of Vaseline oil, focusing on the spokes and hub, the rims, the handlebar, and the stem. Use a clean cloth, slightly soaked in oil; this will protect the components from dust.
> Hang your mountain bike by the frame to limit pressure on the tyres and prevent possible fissures.

IMPORTANT: Cool does not mean cold! Avoid overly hot or cold temperatures at all costs. Do not store your mountain bike in the sun and be careful of winter freeze.
The garage can be a good solution, as long as it stays dry and does not freeze in winter; otherwise, store it inside your house.

Improving battery lifespan

To improve the lifespan of your battery as much as possible, we recommend:

- Reducing your use of it (a mountain bike is not a scooter!)
- Charging the battery with the original charger, and ensuring that the charger is in good condition
- Storing your MTB with a charge level around 60% (Do not leave the battery plugged in beyond 100% and do not store it totally discharged)
- Storing your MTB in the shade or in cool rooms.

When transporting it, also consider removing the battery from your mountain bike and storing it inside your vehicle.

Changing the brake pads

On disc brakes, you need to change the pads regularly. Depending on how heavily you use your brakes, the wear on the pads will be affected. 

If you feel a loss of "bite", a loss of performance, or a squeak in your brakes, your pads may be worn out. To be sure, check the thickness of the pad. If there is less than one or two millimetres left, replace it.

You can replace your brake pads yourself by following this video, or you can bring your EAMTB to a Decathlon workshop so that one of our technicians can replace them. 

Rockrider e-ST900 Electric Mountain Bike
Servicing your fork

The fork is one of the mountain bike components that works the hardest, so it needs thorough maintenance to keep you safe and comfortable on technical trails. We therefore recommend giving it a regular check-up.

There are several things you'll need to do to keep your fork going for as long as possible:

> After each ride, clean any dirt off the dampers and dust seals. This will minimise the risk of dirt getting into the blade. You can also add PTFE lubricant to stop the seals drying out. Wipe off any excess as you don't want it to pick up dust.

> After 50 hours of riding, you can also disassemble your fork, clean it thoroughly, and grease it again. This maintenance is more complex, since it requires you to disassemble the fork. We recommend dropping off your MTB at one of our Decathlon workshops to prevent any risks of damaging your fork.

Checking chain wear

A worn chain will struggle to change gears and will wear out the cassette and chainring prematurely.

You can check how worn your chain is by using a wear indicator. Simply place the indicator's notch between two links and let the other end drop onto the chain. If it fits neatly between two links, the chain is worn and it's important to change it soon, before it damages the cassette and chainring.

We recommend changing your chain when it's 50% worn. Above 75%, you should change the chain, cassette AND chainring, which is why it's best to regularly change your chain: this stops you having to replace your entire drivetrain.

If you use your EAMTB for mobility, use all the different cogs on the cassette, or a lighter assistance mode. It is very common for users to need to replace their entire cassette because the small cog is worn out prematurely due to an assistance mode that is too often in turbo mode, or because the small cog is too worn compared to the others).

REMEMBER: electrical assistance mountain bikes require a reinforced chain.

Rockrider e-ST900 Electric Mountain Bike

Compatible accessories

Bike bottle cage 500

Fit the 500 bottle cage to your E-ST 520 mountain bike's top tube

Rockrider e-ST900 Electric Mountain Bike
Thule easyfold bike rack 

Your bike is compatible with the THULE Europower bike rack available at Decathlon stores.

This bike rack can hold up to two electric bikes.

Bike rack

Your E-ST 520 mountain bike does not come with lights. However, you can fit it with a 6V light provided that it's listed as being "compatible with the Brose T aluminium motor" or 6W at the front and 0.6W at the back.

Our engineers recommend Lezyne, whose products are great value for money.

Remember to check the compatibility!

Warning : In most cases, lights manufacturers supply their lights/cables without connectors. You often therefore have to cut the cable to the right length, strip it, solder it or attach it using a terminal block, and then protect it with electrical tape or a heat-shrink sleeve.

There is a risk involved in handling the bike's electrical components. If you are in any way unsure about what you are doing, then take your bike to a DECATHLON workshop.

Spare parts

Need to replace a part on your bike? You'll find all our spare parts for the E-ST 500 MOUNTAIN BIKE (2022) right here.

ROCKRIDER E-ST 500 (2022)
Men's e-st 500 Check out our spare parts
Spare parts
Women's e-st 500 Check out our spare parts

Get your mountain bike as good as new!

Have your decorative stickers gotten damaged? Or has one of your components been replaced by a standard part with no decoration?
Find the original stickers for your mountain bike at a Decathlon workshop!

Our technicians can print the stickers for your mountain bike on site and place them directly on your bike.

Instructions and certificate of compliance

Rockrider e-ST900 Electric Mountain Bike
instructions diagram

Need mechanical instructions for your E-ST 500 mountain bike?


Need the certificate of compliance for your E-ST 500 mountain bike?


Need electrical instructions for your E-ST 500 mountain bike?


Need instructions for your drive train? 

ROCKRIDER E-ST 500 (2022)

Haven't been able to fix your problem or find what you need?

Please contact one of our technicians who will be happy to help

Rockrider e-ST900 Electric Mountain Bike

Our commitments

ROCKRIDER provides a lifetime warranty on the frame, handlebar and stem of your mountain bike (under normal conditions of use).

All other parts have a two-year warranty.

When you start riding your bike, some components will move slightly. This is why we offer a free tune-up of your mountain bike within six months of purchase. 

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