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ST 520 27.5" Mountain Bike – Navy Blue
  • ST 520 27.5" Mountain Bike – Navy Blue
  • ST 520 27.5" Mountain Bike – Navy Blue
  • ST 520 27.5" Mountain Bike – Navy Blue
  • ST 520 27.5" Mountain Bike – Navy Blue
  • ST 520 27.5" Mountain Bike – Navy Blue
  • ST 520 27.5" Mountain Bike – Navy Blue
  • ST 520 27.5" Mountain Bike – Navy Blue
  • ST 520 27.5" Mountain Bike – Navy Blue
  • ST 520 27.5" Mountain Bike – Navy Blue
  • ST 520 27.5" Mountain Bike – Navy Blue
  • ST 520 27.5" Mountain Bike – Navy Blue
  • ST 520 27.5" Mountain Bike – Navy Blue
ST 520 27.5" Mountain Bike – Navy Blue

ROCKRIDER

8351007

ST 520 27.5" Mountain Bike – Navy Blue

$450.00
18 reviews
14 of 18 people recommends this product
  • ST 520 27.5" Mountain Bike – Navy Blue
  • ST 520 27.5" Mountain Bike – Navy Blue
  • ST 520 27.5" Mountain Bike – Navy Blue
  • ST 520 27.5" Mountain Bike – Navy Blue
  • ST 520 27.5" Mountain Bike – Navy Blue
  • ST 520 27.5" Mountain Bike – Navy Blue
  • ST 520 27.5" Mountain Bike – Navy Blue
  • ST 520 27.5" Mountain Bike – Navy Blue
  • ST 520 27.5" Mountain Bike – Navy Blue
  • ST 520 27.5" Mountain Bike – Navy Blue
  • ST 520 27.5" Mountain Bike – Navy Blue
  • ST 520 27.5" Mountain Bike – Navy Blue
ST 520 27.5" Mountain Bike – Navy Blue
Size :
Not available online

Store Availability

Our team has developed this 27.5" mountain bike with mechanical disc brakes for your mountain bike touring in all kinds of weather, for rides of 2-3 hours.

BENEFITS

Cycling comfort

Enjoy the raised position, adjustable stem, 80 mm suspension and hollow saddle

Directional control

Control your path with the double disc brakes and notched tires.

Efficiency

Efficient cycling thanks to the 27.5" wheels, 24 speeds and aluminum frame.

Easy to use

Use the wheel to adjust the fork to your weight. Easily adjust the saddle.

Lifetime warranty

Rockrider provides a lifetime guarantee for the frame, stem, and handlebars.

Instructions


TECHNICAL INFORMATIONS

WHAT OUR TEAM HAS TO SAY

This ST 520 mountain bike has been entirely designed and developed at the B'Twin Village in France (Lille). We've designed, developed, and tested the ST 520 MTB for comfort and efficiency. This combines to give MTBers confidence to overcome any new obstacle.
We have involved real MTBers at every stage of this bike's design process.
And we hope that the Rockrider ST 520 is everything you could hope for to give you excellent MTB rides.

A unisex mountain bike

Men's or women's mountain bike?
This Rockrider ST 520 mountain bike is unisex.

For greater comfort, the women on our mountain bike team recommend replacing the saddle with the Women's 500 Sport saddle, which is adapted to women's bodies.
A range of Rockrider mountain bikes specifically designed to fit female body shapes is also available (specialized saddle, stem, fork, and brake grips).

HOW TO CHOOSE YOUR ST 520 MOUNTAIN BIKE SIZE

Several sizes available:
S: between 1.50 m and 1.64 m
M: between 1.65 m and 1.74 m
L: between 1.75 m and 1.84 m
XL: between 1.85 m and 2.00 m

If you are on the limit 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).

A COMFORTABLE, PLAYFUL FRAME

For a lighter weight and more efficient pedalling, the Rockrider ST 520 frame has been designed with 6061 aluminum (only 1.9 kg in size M). Our designers have designed and developed it so it is comfortable and easy to manoeuvre. Its slope has been designed to keep your back straighter. The lower bottom bracket helps keep you more stable during turns.

FRONT SUSPENSION TO CUSHION UNPREDICTABLE TERRAIN

Directly adjust the stiffness of the suspension to your weight to more easily travel over roots and stones.

The 80 mm front suspension is designed for slightly uneven trails and helps you overcome your obstacles with no worries. It is based on a mechanical spring and is reliable. And it's easy to look after.

REAR SUSPENSION: NONE

This mountain bike has no rear suspension. This is a "semi-rigid" mountain bike.
Compared to a full suspension mountain bike (with rear suspension), the advantages are clear: lighter weight, you will spend less energy on flat ground. However, if you want more comfort, the ST 520 MTB also exists in a "full suspension" version with a rear shock absorber.

DERAILLEUR & DRIVE TRAIN: HOW TO CHANGE SPEEDS

3 8-speed chainwheels or a wide range of 24 speeds.
2 quick shifters on the handlebars.
Left (chainwheels): control ascents/descents.
Right (speeds): more precise control over your pedalling.

In detail:

- Triple chainwheels: 22, 32 and 42 teeth
- Shimano Altus or Microshift FD-M22 front derailleur
- SRAM X3 rear derailleur
- SRAM X4 shifters, with speed indicators
- SRAM PG820 8-cog cassette, 11 to 32 teeth

HANDLEBARS, STEM, GRIPS: TAKE CONTROL OF THE HANDLEBARS

With its adjustable stem, the ST 520 controls are close at hand. The all-aluminum B'Twin stem is 70 mm (size S), 80 mm (size M/L), or 90 mm (size XL) and can be raised using 5 adjustment intervals: + 0 mm, + 7.5 mm, + 15 mm, + 22.5 mm, + 30 mm.

In detail:

- 680 mm oversized aluminum handlebars
- Soft touch B'Twin sport grips for good grip and a comfortable feel.

SEAT / SEAT POST: Comfortable and sporty seat

Our teams conceived and designed an exclusive saddle for this bike. Suitable for different hip sizes, its "hammock" shape is particularly good for sport touring. The Flex 27.2 mm diameter aluminum seatpost also contributes to its increased level of comfort.

Quick and easy tool-free adjustment of your saddle height using the adjustment lever on the seat post clamp.

MECHANICAL DISC BRAKES: GET A GRIP ON YOUR BRAKING


The HAYES M-X5 mechanical double disc brakes give you gradual, powerful braking at the front and back. While the aluminum Tektro brake levers are light, precise, and easy to hold. Just two fingers are all you need to brake.
Try to get your brakes adjusted at least once a year.

27.5" DOUBLE-WALLED WHEELS & TIRES FOR DRY GROUND

Take on obstacles! The aluminum wheels are effective and sturdy: 27.5" double-walled rims. Their diameter is the perfect balance between comfort and performance. With their 28 spokes, they are lightweight, stiff, and durable. The exclusive 27.5" x 2.0 B'TWIN ALL TERRAIN DRY tires are designed for dry terrain. Their side lugs provide good traction during turns. Recommendations for pressure based on the cyclist's weight are marked on the sidewalls.

PLATFORM PEDALS

The ST 520 is supplied with platform MTB pedals mounted on bearings, made from resin for light weight and safety. If your foot slides on the pedal, there's less risk of injury.

Easily transport and store your mountain bike

Not all rides start on your doorstep. This is why we've made it easy to remove and attach the front and rear wheels. They are equipped with a quick-release system.
A bike carrier will make your life easier if you want to avoid dirtying your car.

ACCESSORIES

Your ST 520 mountain bike is supplied with a bell, lights, wheel reflectors, and pedals.

The frame is compatible with:
- front and rear mudguards,
- stand,
- bottle cage,
- saddle bag,
- rear pannier rack,
- child seat (add an additional pannier rack for sizes S and M to avoid touching the rear wheel)
etc.

OUR ADVICE FOR YOUR FIRST FEW RIDES

Tip No.1
When mountain biking, there is always the risk of a fall: don't forget to wear a helmet.

Tip No.2
Even if the saddle is comfortable, cycling shorts with a pad (saddle-shaped foam) are a real plus for preventing glute pain.

Tip No.3
If you don't want to stop to drink, bring water along in a bottle or water bladder you can access while riding.

Tip No.4
Punctures are always possible, remember to bring a repair kit.

Reviews

3.7/5 18 reviews
14 of 18 people recommends this product
Lives Up To The Expectation
Owen (United Kingdom) Used for 8 to 12 months
Owned this bike for a while now, and other than some unusual sounds coming from the chains, (Maybe something done wrong on my behalf, as it was seemless for the first 6 months) it is a fantastic bike. The gears can be sometimes be a bit iffy, but it deserves the high rating. Would recommend for newcomers that are new to the activity.
Great for the price
James (United Kingdom) Used for 2 week or less
Bought this for my wife for fire roads and leisure riding. Pretty well built for the money and spec is reasonable. Forks actually feel pretty plush. Not sure it would last too long on proper trails but nothing at this price point could.
Fantastic Bike
Malcolm (United Kingdom) Used for 3 to 8 weeks Verified purchase What is a "Verified purchase"?

Where review is marked as "Verified purchase" confirmed by Decathlon, this means that we could verify that the client who filed this opinion has purchased the product from us.

We can confirm purchases for the reviews expressed on a request by e-mail after purchase or when the customer has this review from his personal space.

If a review is not marked as "Verified purchase," this does not mean that the author's review has no experience with the product. They may have given their review directly on the site without unique identification, or the product has been offered or paid by someone else.

The label "Verified purchase" let's help you judge the reliability of a review.
I bought 2 of these bikes, one for me and the other for a friend who was looking to start cycling again. It was near impossible to get hold of the ST520 because of the current Coronavirus situation with little stock or no delivery slots available. I was concerned at the colour being high-viz yellow but have quickly grown to like it.

The building of the bikes took about 15 mins each and just needed the handlebars and pedals to be fitted and some minor adjustments to the brake and gear levers to suit.

The bikes have B'Twin on the downtube and not Rockrider as in the photos but I have been reassured by Decathlon that the bikes meet the current spec. I think it may be some old stock that is being used up due to the current situation. It would have been nice to have been advised of this at the time of purchase.

I haven't cycled in 30 years but I have found the Rockrider ST520 ticks all the the boxes for me and is a delight to ride. It was a bit of a gamble because I bought online with no test ride in store. The good reviews convinced me to go for this bike.

I am mainly using the bike on some gravel tracks and canal towpaths and the bike is great for these.

I have now ridden just over 50 miles on the bike and don't have any problems. It took a few miles to get used to using the gears but they are very easy to use. I changed the weight setting on the front forks to a lower weight than I am and found they absorbed many more bumps and made the ride more comfortable.

I have had to change the saddle to something more comfortable! I just couldn't cope with something that was like some medieval torture device. An old style saddle with springs made it a delight to sit on and absorb the bumps from the rear wheel.

Overall I am delighted with this bike and so glad that I persisted in trying to get hold of one given the current situation.
Poor customer service
Conor (United Kingdom) Used for 3 to 8 weeks
Had only owned this bike for 2 weeks before the chain snapped on me while out on a ride. I'm far from a vigorous rider. And stick to flat road surfaces. So confused why the chain would snap. Regardless I called customer service to see if covered under warranty as a chain shouldnt snap after only 60miles of flat riding. Before I could finish asking the question the person on the phone stated it wasn't his problem and I had to deal with it myself. Utterly unacceptable and unnecessary !! No solutions were provided at all and no help what so ever.
Rockrider ST520 review
Andy (United Kingdom) Used for 3 to 8 weeks
Packaging quality is poor, bike was loose in oversized box with no padding, box arrived open. The bike itself had the handle bars fitted incorrectly, the front and rear brake pads were contacting the discs and the tyres are poor quality and not suitable for mountain biking. Overall the bike, as delivered, was dangerous to ride. After rectifying all issues and replacing the tyres with a thicker lighter MTB tyre I can honestly say this bike is a joy to ride. At this price no new bike on the market compares.
Decent bike
Darren (United Kingdom) Used for 3 to 8 weeks
I do like the st520,, had a problem with the left gear changer for the crank gears on 1st day (before riding it) because the mechanism inside snapped/broke upon changing them whilst setting bike up,, decathlon sent me a new one out as well as some spare inner tubes and now works fine even though I was I bit gutted at 1st,, so I hope the pay better attention to the tension of setting components before letting someone safely ride on of their bikes. Apart from this hickup,, I am actually really happy with the bike the ride is quite a smooth one and us an enjoyable ride and for the price I've had bikes that don't ride as smooth for the same price,, suspension is good now I've set it to the correct adjustment, makes the ride feelefeel better,, wheels and tyres roll quite well for a mountain bike (my road bikes are faster but of course there going to be) so that's a bonus since you can't have ya cake and eat it too,, quite happy with the mechanical brakes levers and rotors (but then again I've always had rektro brakes on all my GT bikes). Handle bars feel great now I've adjusted all the components on them for comfort and grips are good to be quite honest, the seat is slot comfier than say the st100 so that helps when riding every day,, love the chunky headset on the stem looks and feels the part feels quit robust and trustworthy. And the pedals are good,, prefer metal ones but the btwin platform pedals seem okay as it goes, and the bike feels quite smooth when accelerating at not much effort,, they seem to have incorporated this in a good way for an entry bike. All in all I do like this bike the st100 that my partner has is okay too,, but I use bikes all the time hence why I went for the dearer option
I.e. ez fire gears, mechanical disc brakes,, smaller brake levers,, adjustable suspension, comfier seat,, chunkier head set (which is one of my fave parts on this bike,, looks and feels the part,, feel like I could go do some bike trails with it,, (iknow it isnt advised to on an entry bike but I reckon ya could get away with some lighter ones), and the frame feels and looks great no too heavy quite clean looking frame looks slot dearer than it is,, so for the price alone I can't really doubt this bike but I hope time doesn't tell but then again unless your just gonna ride it to the park for a picnic on a Sunday and that's it every bike rider knows that regular service and correctmcorrect will make your bike last alot longer. Can't fault the bike appearance is great feels great,, still an entry level bike but I reckon it's one of the better end of them.
The front derailleur is this bike's fatal flaw
Claudio (United Kingdom) Used for More than 1 year
- In April 2019 I bought a Rockrider 520.
- In June 2019 I returned the bike to the shop where I purchased it, since the front shifter/dérailleur went out of position and got stuck on the rear wheel while I was riding the bike, blocking the wheel suddenly and making me risk a fall. The issue appeared when the bike was less than two months old, after less than ten rides, for a total mileage of less than 50 miles, and no hard use.
- Later on the same month the bike was returned to me, and a brief test proved that the issue was still there. It had NOT been repaired.
- The bike was finally replaced in late June 2019. The replacement bike did not show the issue, but I did not use it much since March 2020.
- On VE-Day75 ( 08/05/2020), I parked the bike on a rack at RAF Memorial in Englefield Green. I picked up the bike and I could hear there was a problem with the gear shift. As I changed gear, the front derailleur moved out of place and got stuck on the rear wheel while I was riding, causing the rear wheel to lock. I did not crash only because I was riding extremely slow, since I did not trust the bike.

So, one year on, this bike shows the same issue. And it looks like many other reviews are about similar problems with the front derailleur. I would most definitely like to see Decathlon fixing my bike, but I would like even more for the company to RECALL the bike, since this is clearly a design flaw. Bike like this can only damage the value of a brand.
delighted
toni (United Kingdom) Used for 3 to 8 weeks Verified purchase What is a "Verified purchase"?

Where review is marked as "Verified purchase" confirmed by Decathlon, this means that we could verify that the client who filed this opinion has purchased the product from us.

We can confirm purchases for the reviews expressed on a request by e-mail after purchase or when the customer has this review from his personal space.

If a review is not marked as "Verified purchase," this does not mean that the author's review has no experience with the product. They may have given their review directly on the site without unique identification, or the product has been offered or paid by someone else.

The label "Verified purchase" let's help you judge the reliability of a review.
my son is over the moon with his choice.
Average quality product
Fleseriu (United Kingdom) Used for More than 2 years
First, I have this bike since 2nd of January 2018, and it took the abuse pretty well, even tho I did some pretty big jumps with it. She passed one year and the things changed, I spent in 1 year more de 3 times of the bike's price on upgrade parts, because they are really cheap. The derailleur, the tires, and the brakes are the biggest thing you need to change if you have in mind to really abuse this bike. So I recommand it if you are going to use it as a trekking bike, or really gravel roads and only if, I reapeat, only if you are a really good rider, you can buy this bike for more than gravel roads.
Awful bike and service by staff
Sarah (United Kingdom) Used for 2 week or less
Brought this bike a month again. Within the first day I had a puncture whilst riding over stones (WHICH THE BIKE IS MEANT FOR) then both reflectors on the rear tire flew off. I spoke to staff and that said it’s my own fault. I don’t see much point in having a mountain bike if the crappy tires puncture whilst riding over stones!! NOT HAPPY
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