ROCKRIDER ST 100 U-fit MTB Red

The recommended average tyre pressure is 1.8 bar.If you're looking for more comfort and grip AND/OR if you weigh under 70kg, you can reduce the pressure by 10% but without dropping below 1.6 bar (the minimum recommended pressure). On abrasive terrain, however, this will increase the risk of punctures.You should check the pressure of your tyres regularly.

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.

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.

There's no need to bed in your V-brakes and pads. You should know, however, that when the pads come into contact with the black trim on your rims for the first time it will make quite a noise. Don't worry, though. As you use your bike and apply the brakes more and more, a fine film of rubber will form over the rims and the noise will gradually disappear.

When you take your new bike out for a ride for the first time, a lot of parts move around and fall into place. You'll hear the spokes on your wheels creak because of the residual torsion in them. Your bike is fitted with double-walled rims, which help make the wheels more solid. That means they should not buckle in any way at all. If they do, then call in at one of our DECATHLON workshops to have them repaired free of charge: 1. As part of a free check-up in the first six months following the date of purchase. 2. As part of our €1 damage insurance plan (valid for two years). Message for parents: young riders like to do tricks on their bikes (wheeling, skids, jumping off kerbs, etc). If done too often, however, they can cause play in the rear hub and buckle the wheels. If your child performs these tricks on a regular basis, speak to them and let them know the problems they can cause.

It's a sad fact of cycling that everyone gets punctures. - The terrain (thorns, bramble bushes, glass, nails, etc)- and use of the bike (catching tyres on obstacles such as stones, steps, kerbs and potholes)are the most common causes of punctures and pinched tyres respectively.If you keep suffering punctures, there can be several factors at play:- The wheel has not been assembled properly in the factory and a spoke keeps piercing the inner tube.- A substandard tyre or inner tube.- A badly repaired puncture or a foreign body (thorn, piece of glass, shard of metal, etc) stuck on the rim or in the tyre.It's important to find out what is causing the puncture and to remove any foreign bodies before repairing it.I don't know how to put a tyre on or take one off so how am I going to repair or change an inner tube?1. The simplest thing to do is not to touch your wheel and use a can of puncture repair foam as a temporary solution: Screw the end of the tube on to the valve of the punctured tyre (with the valve pointing down) and press down to inject the foam. The tyre will regain its shape and hardness, allowing you to get home. 2. If you've taken out our 1-euro damage insurance plan, you can have your tyre fixed at one of our DECATHLON workshops. 3. If you want to repair or change the inner tube yourself, then check out the tutorial videos below.  

There are one or two things you can do to make your fork "softer":1. Adjust the stiffness: check the section "ADJUSTING THE STIFFNESS OF YOUR FORK"2. Do some basic maintenance: using a simple oil can. Squirt some oil on the pivots of the fork and move it around to work the oil into the blades.3. Have the bike fully serviced in a workshop.

There could be several reasons why your gears (chainrings) are not shifting correctly.1. Check the position of the housing ends.Housing ends that are out of position can obstruct the derailleur cable when it is being pulled and prevent the gears (chainrings) from shifting smoothly. If a housing end is out of position, push it back into place.2. The cable and housings may have jammed up.If the smallest gears (chainrings) do not move down, if the derailleur doesn't move even when the gear shifter is operated, then the cable and the housings have jammed up. They need to be replaced. 3. Take your mountain bike to a DECATHLON workshop or replace them yourself with the help of this video.NB: If you regularly use your mountain bike in wet or muddy conditions or if you wash it a lot, then you will need to replace the housings and cables more often. We strongly advise you not to use a pressure hose to wash your mountain bike as it will force dirt into the housings.

There could be several reasons why your gears (cogs) are not shifting correctly.1. Check the position of the housing ends.Housing ends that are out of position can obstruct the derailleur cable when it is being pulled and prevent the rear gears (cogs) from shifting smoothly. If a housing end is out of position, push it back into place.2. The cable and housings may have jammed up.If the smallest gears (cogs) do not move down, if the derailleur doesn't move even when the gear shifter is operated, then the cable and the housings have jammed up. They need to be replaced. Take your mountain bike to a DECATHLON workshop or replace them yourself with the help of this video.3. Take your mountain bike to a DECATHLON workshop to have the derailleur adjusted. 4. You should also check that the derailleur dropout is not twisted. If it is, check the section "YOUR DERAILLEUR DROPOUT IS BROKEN".   NB: If you regularly use your mountain bike in wet or muddy conditions or if you wash it a lot, then you will need to replace the housings and cables more often.We strongly advise you not to use a pressure hose to wash your mountain bike as it will force dirt into the housings. 

The lever is spongy and/or touches the handlebars before you can brake: Loosen the thumbwheel and the locknut to adjust the cable tension so that the brake lever is firm but not too hard. Once you've got the setting right, tighten the locknut against the brake lever.Drop in at a DECATHLON workshop and get one of our technicians to do it.

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.

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: a chain tool, a new chain and a quick-release link. Put the chain on the cog and on the smallest chainwheel.  Remove the quick-release link using a 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 chainwheel. 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 on the right position.

We recommend you use the 500 Adult chainstay stand.

We recommend you use the 700 mountain bike front mudguard.

We recommend you use the 700 mountain bike rear mudguard.

Use the Flash mountain bike front mudguard: it's easier and quicker to fit.

Use the Flash mountain bike rear mudguard: it's easier and quicker to fit.

We recommend female riders change the saddle for an ergonomic 500 women's sport saddle, which is better suited to their body shapes.   

You need to drink water when you're cycling: we recommend the 550ml bottle.  You'll also need a bottle cage to keep your water close to you.   

Use the 500 bottle cage to keep your water bottle handy.

For your family outings choose the Polisport GROOVY child bike seat - rack mount.

We recommend you use the 500 foot pump.

There’s always a risk of picking up a puncture when you’re out and about on your bike, which is why you need some puncture repair spray. The spray fills the inside of the tyre with foam, allowing you to get back home. 

The 500 saddle cover offers extra comfort.

This 0.5l saddle bag is easy to fit and is ideal for carrying all your kit: multi tools, puncture repair spray, etc. 

For people who need to stay in touch. The 500 smartphone holder lets you fit your phone to the handlebar.

We recommend the 300 bike rack for carrying your ST 100 mountain bike, whether you're cycling at home or on holiday.