This 27.5" mountain bike is designed for you to enjoy two- to three-hour rides all year round. Discover the efficiency and the playful side of the ST 540 mountain bike, with its 27.5" double-walled rims and hydraulic disc brakes, and the simplicity of its 18-speed double chainring. It gives you a comfortable ride too.
The recommended average tyre pressure is 1.8 bar.
Your handlebar is set in the highest position to help keep your back raised, which is the most comfortable position for riding.
For improved aerodynamics and more effective pedalling, you can lower your handlebars to lower your body. This will cause you to lean forward and adopt a racing position.
Follow the steps in this video to move the headset spacers below the stem and lower the handlebars on your bike.
Your ST 540 bike frame is fitted with a quick-release lever.
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.
The BTWIN U-Fit fork has been designed to make adjusting it as easy as can be. A genuine innovation: weigh yourself and then turn the thumbwheel on the fork until your weight appears in the window. This will make the spring harder or softer, in line with your weight.
The brake pads and discs on a new bike are new themselves and don't work to their full potential.
You can avoid the risk of the inner tubes on your mountain bike getting punctured or pinched by switching to TUBELESS.
To do this you'll need to buy the following:
- A pair of TUBELESS tyres:
DECATHLON: ALL TERRAIN 9 SPEED 27.5X2.10 TUBELESS READY MOUNTAIN BIKE TYRES / ETRTO 54-584 (8386245)
- 21mm rim tape:
ALLTRICKS: NOTUBES YELLOW 21MM RIM TAPE FOR FIVE RIMS
- A pair of Schrader TUBELESS valves:
ALLTRICKS: PAIR OF NO FLATS JOE'S SCHRADER TUBELESS 36MM VALVES (AUTO)
DECATHLON: TUBELESS READY TYRE AND WHEEL SEALANT (8550735)
STEPS TO FOLLOW:
When you take your new bike out for a ride for the first time, a lot of parts move around and fall into place.
It's a sad fact of cycling that everyone gets punctures. - The terrain (thorns, bramble bushes, glass, nails, etc)
There are one or two things you can do to make your fork "softer":
There could be several reasons why your gears (chainrings) are not shifting correctly.
There could be several reasons why your gears (cogs) are not shifting correctly.
The lever is spongy and/or touches the handlebars before you can brake:
A twisted dropout causes the derailleur to become misaligned, preventing it from doing its job correctly. Look at your bike from behind and check to see if the derailleur is straight.
So you've broken your chain.You've got two options: 1. Repair it yourself with the help of this video. You'll need a chain tool and a quick-release link. 2. Drop in at one of our DECATHLON workshops and have it done by one of our technicians.
These videos show you how to repair your bike and replace parts yourself.
Putting on/taking off a rear wheel - Repairing a puncture
- Changing an inner tube - Adjusting the height of the handlebars
- Repairing a chain - Replacing a derailleur dropout
Our YouTube channel has a lot more content. Have a good look around.
PUTTING ON/TAKING OFF A REAR WHEEL
REPAIRING A PUNCTURE
CHANGING AN INNER TUBE
ADJUSTING THE HEIGHT OF THE HANDLEBARS
REPAIRING A CHAIN
CHANGING THE DERAILLEUR DROPOUT
To clean your bike properly, you'll need some bike cleaner, a sponge and a brush. Spray the bike with a hose before applying the cleaning products. Use the sponge and brush to apply the products. Allow the product to act before rinsing the bike. Rinse it from a distance to avoid damaging mechanical parts. Finally, dry the bike with a soft, clean, dry cloth.
To clean and lubricate your drive train, you will need a degreaser spray, a soft bristled brush and a lubricant. The first step involves covering the brake disc with a clean cloth to prevent any lubricant from getting on to it. Then apply the degreaser to the whole of the drive train and scrub the cassette, chain and derailleur jockey wheels with the brush. Leave to act for a few minutes before rinsing the degreaser off from a suitable distance. Allow the drive train to dry before applying the lubricant. Shake the lubricant and apply to the inside of the chain, where it will work best.
Is your drive train cable dirty, rusty or damaged or are your gear changes stiff, random or not as slick as they should be? If so, the cable needs changing.You'll need a pair of pliers, a screwdriver, cable cutters, an Allen key and a new derailleur cables and housings kit. Start by removing the cable from the housing. Remove the hood from the gear shifter, move the indicator to the last gear and cut the cable. This will allow you to remove all of the cable and then the housing. Cut the housing to size and fit the end caps on the end of the cable, which is now ready to fit. Thread the cable through the shifter and push it through the housing. Then put the hood back on the shifter and attach the cable to the derailleur. To adjust the drive train, tighten the cable if the gears do not shift up easily and slacken it if they do not shift down smoothly. Finally, cut the cable and use the pliers to attach the end cap to it.
You need the following to repair a puncture: a pump, a basin of water, a cloth and an inner tube kit. Put a little pressure on the inner tube. To find the puncture, submerge the inner tube in the basin of water. Once you've spotted it, dry the inner tube with a cloth and scrape the area around it with the sandpaper provided in the kit. Scraping the inner tube will allow the glue to adhere better. Apply the glue generously around the hole and wait for three to five minutes. Place the patch over the hole and hold it there for a few minutes. You can then fit your inner tube back into the tyre.
You will need the following: new brake pads, a flat screwdriver and a 3mm Allen key. Remove the wheel first of all. Then use the screwdriver to move the pads apart and put the pistons back into their original position. Take out the pin holding the pads in place and remove them from their housings. Position the counter spring between the new pads. Insert the new pads in the brake caliper and then put the pin back in place to complete the process. Put the wheel back on and check to make sure that the brake pads are properly in place and do not rub against the disc.
You will need a 5mm Allen key. Unscrew the brake caliper, spin the wheel and operate the brake lever. It is important to keep the brake lever engaged before screwing the caliper back in place. Check to see that the disc and the pads are still in contact.
You will need a new derailleur dropout that fits your bike (check the "SPARE PARTS" section) and a 5mm Allen key. Take off the wheel and the damaged derailleur dropout. Position the new dropout on the frame. Remove the old dropout part from the derailleur before fitting the new one with the Allen key. Fit the derailleur on to the new dropout and check the gears.
You will need the following: a chain tool, a new chain and a quick-release link. Put the chain on the cog and on the smallest chainring. Remove the quick-release link using the quick-release chain tool and then remove the chain from the drive train. Put the new chain on the last of the cogs and on the smallest chainring. This makes it easier to determine its optimal length. The chain should pass close to the top pulley of the upper jockey wheel on the derailleur. Once you've determined the length of the chain, use the chain tool to cut it as required. Then fit the quick-release link on the chain and turn the pedal to position the quick-release lever on the top part of the chain. Press it with your hand to check that it is in the right position.
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.