RockRider 520 Review from Decathlon, B’Twin

I bought this bicycle around 3 months ago. It was an upgrade from my old RockRider 340. I wanted a better bicycle with better brakes, and why not, to jump stairs and do some tricks.

However, the Rockrider 520 is just a entry level mountain bike unless you are pretty light weight, around 50-60 kg, then you can do these tricks with it, jump stairs.

There are a lot of videos on YouTube with kids doing these kind of tricks.

If you are more heavy, around 80-90kg, you need an enduro bike to do these tricks.

What the Rockrider 520 can do is to pass bumps and road pits without any issues. The bike is a pretty good hardtail for the price, around 400 dollars.


Rockrider 520 comes equiped with a pretty basic saddle, one of the cheapest from Decathlon (it should be replaced or adjusted to the right angle, otherwise it will cause pain).

Very cheap pedals, 3-4$ plastic pedals that should be replaced.

A no-name front derailleur (called Micro Shift, pretty unknown brand). The front derailleur works though, even though on some bikes it doesn’t and needs proper adjustement. This is if you are unlucky to get a bicycle with a bad front derailleur.

The transmission is from SRAM, the front rings, the rear cassette and rear derailleur which is SRAM X3. SRAM X3 does a great job, shifts the gears great.

SRAM X3 is an entry level MTB rear derailleur but as I said, it does a great job on this bicycle.

The frame is made of aluminum, we have aluminum seatpost, aluminum handlebar.

The fork is called UFIT, 80mm, it looks like it’s made of steel. It has a weight adjustment. Can’t say it does a good job. It looks cheap and so far, it feels worse than the old 100mm Suntour fork from the previous version of Rockrider 520.

We have Hayes mechanical disc brakes with Tektro aluminum levers. This setup does a good job even though the bicycle might come with the brakes not being adjusted and the disc will rub on the brake pads when the wheel spins.
The brake system is solid, nothing to complain about it.

We have SRAM shifters, made of plastic, pretty decent but not that great overall, they look and feel entry level.

Standard B’Twin MTB tires, 27.5 * 2. The same tires from Rockrider 340. Pretty bad tires overall. You will get a lot of punctures with these tires. I would replace the rear tire right away with something better. I got Michelin Wild Grip’r 27.5 * 2.2 on the rear and so far it does a great job. Even though the standard RR 520 tire makes the bike to go a bit faster since it’s thiner.

Design, how good this bicycle looks?

The frame looks solid, has an aggressive look. The bike doesn’t look cheap. In fact, because of the matte paint, it looks like it is made of carbon.

It comes in 4 versions, 4 colors. I got the black one. It has some blue markings, stickers. And the B’Twin text with dark gray which looks great.

I really like how it looks, even though I would really love to see a version with glossy paint, maybe green or dark blue. It might look amazing, but I guess this is how B’Twin likes to brand their bicycles, making them look like they are made of carbon.

The stem looks nice and so is the front fork with the some kind of rear design that looks unusual compared to other forks.

The rear looks like from a classic MTB, nothing to complain.

Major issues with the bicycle

Clicking, ticking. After 3 months, I’ve noticed some clicking sound coming from the bottom bracket. It probably needs replacement. And this after just 3 months of riding the bicycle in very good conditions. As I said, no tricks, no jumping stairs or anything.

The front hub makes some ticking noise. I’ve open the hub inner parts, put more grease there. It has 9 small balls bearings there on each side. Usually the cones are too tight and need to be adjusted. With some tools (you need a cone key, ask Decathlon for one when you get the bicycle) and with care, anyone can do this, even a non technical person.

But this is annoying because the bicycle should be properly adjusted when you buy it.

As I mentioned, the disc brakes might rub when the wheel spins, will need adjustment.

On high speed, for some unknown reason, the disk brakes might produce some annoying sound because they move or just rub the brake pads. But this at really high speed, over 40km/h.

The saddle might create some unwanted sounds, but it can be replaced with something better and more comfortable.

Also, the front derailleur might not work properly. It can be adjusted or replaced if it’s broken. Also because of it, the chain might rub the derailleur and you won’t be able to use the fastest speeds from the cassette.

The good parts

The frame is solid, the bicycle looks great overall.
It can be upgraded if you want to make this as your hobby, fix and work on it, improve it, upgrade it. You can get better grips, put lights, get better tires, saddle, pedals.

The handlebar, frame, rear derailleur, saddlepost, rims are solid, good quality overall.

I ride the bicycle just around the city. There are tons of road pits and because of that the MTB is the only way. And the bicycle feels great. It’s a bit slow but it is what it is. Can’t use a road bike or a race one.

The max speed can go to 40-45km/h. Depending on your weight.

If you are light, this bicycle can be great for you. Probably you won’t have much issues with it.


For 400$, this bicycle is not bad but it’s not great either. If you don’t might having trouble with it, the kind of issues I’ve mentioned in this article, then it can be great for you.

If you have more money to spend on a bicycle, get something more expensive, better equipped and better adjusted. If this is your budget and you don’t mind having to upgrade, the Rockrider 520 is a good choise for you.

Overall, I like it, can’t say that it’s a bad bicycle but it’s too bad Decathlon is not adjusting them properly when they sell them.
It’s a great upgrade from Rockrider 340.

If you have any questions, please leave in the comments.