An MTB that's efficient and easy to ride! Enjoy the precision and light weight of the ST 120 MTB with its single chainring (1x9 speed) and mechanical disc brakes. Change speeds with ease!
The average recommended air pressure is 1.8 bar.
Your handlebar is factory set at its highest position (upright riding position, which is the most comfortable).
For a more aerodynamic position and greater pedalling efficiency, you can lower your handlebar to stretch out your riding position (a more sport-oriented position with the back more bent forward).
To do this, simply follow the steps described in this video to remove the spacers under the bike stem.
The B'Twin U-Fit fork is designed to make adjustments as easy as possible. Simply turn the dial until you see your weight indicated on the back of the fork. Turning the dial increases or decreases the compression of the spring to adjust it to your weight. That's innovation!
When you first get your bike from the store, the brake pads and discs are brand new and therefore the initial braking performance is very low (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 "freeze up". To avoid this issue (which can render the brakes completely unusable), we recommend first "breaking in" your brakes. This takes about 10 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.
The first time you ride your brand new bike, it's normal that many of its components will move about slightly and settle into their proper places. This is the case of your wheel spokes which you might hear make a "cracking" sound which is naturally due to the residual torsion built up during assembly. Your bike is equipped with sturdy double-walled rims (on the inside of the wheel), so your wheels should be straight and not bent. In the unlikely event a wheel is or becomes slightly bent or twisted, please bring your bike to any Decathlon workshop and they will make the adjustment free of charge, either: 1- As part of the free tune-up available within 6 months of the date of purchase of the bike. 2- Covered by the €1 extended repair warranty, if purchased (good for 2 years). A note for parents: Some technical manoeuvres by young riders (wheelies, skids, jumping a curb, etc.), if repeated too frequently, can also cause some play in the hub of the back wheel and cause the rims to twist. If you notice that your child is doing these types of bike tricks frequency, it's a good idea to make them aware of this issue.
Unfortunately, a flat tyre is something that can happen to any of us. The terrain (thorns, brambles, glass, nails, etc.),
There are a few things you can do to "soften" your fork:
There could be several reasons the chain isn't shifting properly between cogs on the rear cassette:
Your brake lever is too easy to squeeze and/or touches the handlebar before braking action begins: Unscrew the barrel and the locknut until the cable is sufficiently tight and the brake lever is firm but not too hard. Once you've got the tension right, tighten the locknut firmly against the brake lever to secure the setting.
Did your chain break? You have two options: 1- You can repair it yourself using our video tutorial. You'll need a quick-link and a chain tool. 2- Visit a Decathlon workshop to have the operation done by one of our technicians.
The following tutorial videos tell you everything you need to know to repair or replace certain parts on your bike.
- Installing/removing a rear wheel - Repairing a flat tyre
- Changing an inner tube - Adjusting the handlebar height
- Repairing a chain - Replacing the derailleur hanger
You'll find more helpful video content on our YouTube channel. Check it out!
INSTALLING/REMOVING A REAR WHEEL
REPAIRING A FLAT TYRE
REPLACING AN INNER TUBE
ADJUSTING THE HANDLEBAR HEIGHT
REPAIRING YOUR CHAIN
REPLACING YOUR DERAILLEUR HANGER
To clean your bike properly, you'll need some bike cleaner, a sponge, and a brush. Rinse off the bike with a hose (not at high pressure), and then apply the bike cleaner. Next, use the sponge and brush to apply the cleaner effectively. 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 cloth that is dry, clean and soft.
To clean and lubricate your drivetrain, you'll need a degreasing spray, a suitable brush, and bike lubricant. The first step is to protect your brake disc with a clean cloth to prevent any grease or lubricant getting on it. Next, spray the degreasing agent onto the entire drivetrain, scrub the cassette, the chain, and the rollers on the derailleur with the brush. Let it sit for a few minutes before rinsing with a hose from a moderate distance. Wait a little while to let the drivetrain dry before moving on to the greasing step. For greater effectiveness, shake the can of bike lubricant and spray on the inner side of the chain.
Is your drivetrain cable dirty, rusty, damaged, or do you find changing speeds to be difficult or unreliable? If so, you need to replace your drivetrain cable. To do so you'll need a pair of pliers, a screwdriver, a wirecutter, an Allen key, and a new set of derailleur cables and cable housing. First, remove the cable from its housing. Start by removing the shifter cover, and placing the indicator on the highest gear; then cut the cable to be able to remove the entire cable, followed by the housing. Next, measure out how much cable housing you need against your bike, cut it, and put caps on either extremity. Then install it on the bike. Install the cable on the shifter and pull it through the housing. Once done, put the cover back on the shifter and attach the cable to the derailleur. To adjust the drivetrain, tighten the cable if you have a hard time shifting to higher gears, and loosen it if you have a hard time shifting to lower gears. Once adjusted, cut the cable and put a cap on the extremity using a pair of pliers.
To repair a flat tyre, you will need: a bicycle pump, a basin with water, a dry cloth, and an inner tube repair kit. Partially inflate the inner tube. Submerge the inner tube in water to locate the puncture by the source of the bubbles. Once you have located the puncture hole, dry off the inner tube with the cloth and rub the spot to be repaired using the sandpaper included in the inner tube repair kit. This prepares the inner tube for glueing and ensures that the patch sticks to the inner tube as securely as possible. Generously apply glue to the inner tube around the hole and wait 3 to 5 minutes. Then apply the patch to the hole and hold it in place for a few minutes. You can now install the repaired inner tube into your tyre and onto your bike!
To do this, you will need: a chain tool, a new chain, and a quick-link. Place the chain on the largest cog and the smallest chainring. First, remove the existing quick-link using the quick-release tool, then remove the chain from the bike. Place the new chain on the largest cog and the smallest chainring in order to more easily define the optimal chain length. Pull the chain down, pass it under the upper pulley of the derailleur. Once you've defined the correct length, use the chain tool to cut the chain. Lastly, install the quick-link onto the chain, turn the pedal so as to position the quick-link on the upper part of the chain, and use your hand to apply pressure and ensure it is firmly locked in place.
Please contact one of our technicians who will be happy to help
ROCKRIDER guarantees the frame, handlebar and stem of your mountain bike for life (in normal conditions of use).
The guarantee for other parts is two years.
As soon as your child starts using the bike, some components will move slightly. It's for that reason that we offer a free check of your mountain bike six months after purchase.