Rockrider E-ST 520 Electric Mountain Bike Review

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Decathlon do it again with the Rockrider E-ST 520 electric mountain bike

Decathlon seem to be constantly pushing the boundaries of value with their latest e-bike range, and just when I thought it couldn’t get any better they go and release the Brose-powered Rockrider E-ST 520 electric mountain bike. In this review, I will take a closer look at the specification of a bike that bridges the gap between the E-ST900 and E-ST500.


I’ve just finished looking over the spec of this latest e-bike from Decathlon, and it looks like another winner! At the moment there are no, half-decent mid-drive e-MTB’s available in this price bracket. For potential buyers who don’t want to spend over £1500 on an electric bike, the new Rockrider E-ST 520 neatly fills the void between the £1000-£1500 price bracket.

rockrider e-st 520 electric mountain bike

So what does the new Rockrider offer for the price? Well, as it turns out – quite a lot for your money. For starters there’s the excellent Brose-T mid-drive motor with 70Nm of torque and a 36v 11.6Ah battery. As far as components go, there is Microshift’s Advent 1 x 9 groupset with an 11-42 cassette, hydraulic disc brakes and even Rockshox suspension forks.

The frame and finishing kit looks more or less identical to the more expensive E-ST900. I’m really excited about this bike as it is finally bringing a decent-spec mid-drive e-MTB within the reach of more potential buyers.

Electric Components

The new Rockrider E-ST 520 uses the same Brose-T motor as its pricier counterpart, but with one difference. On the E-ST900 the Brose motor has modified firmware which allows the motor to produce up to 90Nm of torque. This version seems to have standard firmware, which still means a very respectable 70Nm. Out on the trails, the extra torque of the more expensive bike would only really be useful on steep, technical climbs.

brose t motor on the rockrider e-ST520 e-mtb


The LCD display on this model is also slightly different, although it seems to offer the same functionality and the display is still right next to the left-hand grip. There are also the same 3 assist levels 3: Economy, Standard, and Boost.
There’s also a whole host of useful information:

  • Stopwatch
  • Current speed
  • Average speed
  • Maximum speed
  • Distance covered
  • Total distance
  • Battery level
  • Remaining battery range (in km)
  • Pedestrian assistance mode
  • Reset

lcd display on the rockrider e-st 520


The lithium battery pack uses the same high quality Samsung or LG cells and has a total energy capacity of 417Wh or 36v 11.6Ah. This should give the rider a potential range of up to 60 miles when ridden carefully.

The 36v 11.6Ah battery

Bike components

Again, Decathlon has provided a specification that you wouldn’t usually find on an electric mountain bike at this price point. A decent 1 x 9 drivetrain with big gear range, powerful hydraulic brakes and even Rockshox forks.


This e-bike uses a Microshift Advent 1 x 9 groupset, which is actually a pretty decent system. When compared with the Shimano Deore M6000 drivetrain found on the E-ST900 there really isn’t a lot in it apart from a bigger jump between some of the gears.  For those of you unfamiliar with Microshift, they are a Taiwanese company that was founded in 1999 and a lot of their components are used on mountain bikes, gravel bikes and road bikes.

microshift advent 1 x 10 gearing

Although they are considered a budget brand, I have used microshift on several bikes and I’ve always found gear shifting to be crisp and precise. I used to own a Riverside 900 and that had Microshift 1 x 10 and it always worked flawlessly.

Advent is one of Microshift’s latest groupsets, and uses a clutched rear derailleur with an 11-42 9-speed cassette paired with a Chainflow 34t front chainring – with gearing like that you’ll be able to remain seated, even on steeper climbs.


The Hydraulic brakes are decent Tektro  TKD88 with 180mm rotors front and rear, although thy are fairly entry-level, these brakes will provide more than enough stopping power for most riders.

Wheels and Tyres

A decent set of 27.5″ double-walled alloy rims are fitted with alloy hubs with sealed bearings – 28 spokes at the front and 32 at the rear to increase durability. These rims can also easily be converted to run tubeless tyres using rim tape, vales and sealant.

Tyres are decent Hutchinson Cougar 27.5″ x 2.4″ which will provide decent grip on a multitude of terrains.

close up of the rockrider e-st 520 frame

Front Suspension

Rockshox 30 Silver coil-sprung front forks are entry-level, but again will provide more than enough suspension for the average recreational rider. With 120mm of travel and rebound adjustment with lock-out.

rockshox 30 front forks

Finishing Kit

The finishing kit on the E-ST 520 is all Decathlon branded, and looks identical to what is fitted to the more expensive E-ST900. The handlebars are 720mm wide and there is an Ergofit saddle.


This frame looks identical to the one used on the E-ST900, a decent sturdy frame with relaxed geometry suited for the novice or intermediate rider.

Who is the Rockrider E-ST 520 bike aimed at?

For riders wanting to have all the benefits of a decent quality mid-drive hardtail electric mountain bike without having to fork out a couple of grand, the E-ST 520 is ideal. Just like its more expensive counterpart it’s going to be incredibly versatile and be suitable for use on or off the road. There are the usual mounting points for a rear rack and mudguards, making this model suitable for commuting, leisure riding and hitting the trails on the weekend.


I’m going to see if I can get hold of one of these for a full test in the near future. I think for £1399 it’s an absolute bargain. I was impressed enough with the Rockrider E-ST 900 but the E-ST 520 is £200 cheaper and there really isn’t an awful lot in it.

rockrider e-st 520 electric mountain bike review

It really boils down to whether you need the slightly more powerful motor and battery. I think Decathlon have released another winner here. There’s been a big gap in pricing for electric mountain bikes. £1000-£1200 will usually buy you a good hub motor e-MTB, but when it comes to mid-drives, there was always a jump of around £300.

What the Rockrider E-ST520 does is fill that gap in the market perfectly. It will also make it a more tempting proposition for people wanting to buy through the Cycle to Work Scheme.

Another great value electric mountain bike from Decathlon, I look forward to trying this one out.

Buy from Decathlon UK
Buy from Decathlon Netherlands

If you have purchased one of these recently, please feel free to leave feedback below in the comments section. Thanks for reading.

Decathlon Rockrider E-ST520 Electric Mountain Bike


Value for Money




Battery Range



  • Nothing comes close at this price
  • Smooth Brose-T mid-drive motor
  • Decent all-round specification


  • What's not to like at this price!


Passionate E-Bike advocate and enthusiast. 5 years experience converting bikes for customers primarily using Bafang and Tongsheng electric bike motors.

6 thoughts on “Rockrider E-ST 520 Electric Mountain Bike Review

  • Value for Money




    Battery Range


    For Daniel, if he hasn’t still discover how to reset KM and Time of the trip. just press and hold ‘-‘ for 8 seconds, and you ‘ll get it. Manual is too short, but this is explained.

  • Can we fit a normal st 520 with electric system?

    • Hi,

      It should be possible to convert an ST520. I’ve converted a few Decathlon MTB’s over the years so it should be fairly straightforward. Here is my article on building a DIY e-bike. You should be able to fit either a Bafang or Tongsheng mid-drive.

      All the best,

  • Does anybody know what the 3 settings are on the est520 ? 1 switches between kph and mph but 1 brightens and dims the display what does the 3rd do

  • Value for Money




    Battery Range


    Hi ,I had one of these delivered yesterday for the wife,there’s nothing out there to match it for the price, unfortunately the bikes manual is only one page thick? and lacking in any detailed information about the LCD controller, were still trying to workout how to reset the trip computer, any ideas ? I managed to switch it from km to mph so just need to keep fiddling. We took it out for a ride yesterday and covered 17 hilly miles, half on the road and half on forest trails, and ended the day with two bars still remaining in the battery. I’ve got to say the bike has pasted my expectations in build and motor quality,I’ve ridden quite a few e-bikes but this Brose T motor is so quite I can’t hear it. Early days though and I will have better idea how the bike and electrics hold up over the next 12 months.

    • Hi Andrew,

      Thank you for sharing your feedback, glad to here you’re pleased with the bike. Regarding the display – if my memory serves me correct, it may be worth pressing and holding the ‘+’ key until the mileage flashes, then short press the on/off button. Hopefully this will work, if not try the ‘-‘ key.

      All the best,


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