rockrider e-st100 electric mountain bike review

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Hot on the heels of their popular E-ST500 e-MTB, Decathlon has just launched an even cheaper e-bike for the budget conscious.  The all-new Rockrider E-ST100 looks like it could be a hands-down winner in the best electric mountain bike under £900 category. Read my review below for more info.


Decathlon has really ‘upped their game’ in the last 12 months releasing some excellent value e-bikes. When it comes to the very popular electric mountain bike sector, they now pretty well much have everything covered in the sub £3000 market.

Previously the E-ST500 was their only electric mountain bike available for under £1000, but now there is an even cheaper model available – the Rockrider E-ST100.

At a glance, the new bike looks very similar to the more expensive option, but the differences are very subtle. There has been some cost-cutting here and there to keep the price down. For example, the battery capacity is down from 417Wh to 378Wh, the mechanical brakes are by Tektro (as opposed to Hayes) and there is 20mm less travel in the front suspension. The tyres are slightly narrower (2.2″ vs 2.4″) and there’s an 8-speed with an 11-34 cassette as opposed to a 9-speed 11-36.

All these differences are arbitrary if you’re looking for a cheap hack, that will get you from A to B on a multitude of surfaces without much fuss. Let’s have a closer look at the specification.

Electric Components

Nothing new to report here. As far as I can make out the E-ST100 uses the same rear hub motor as the E-ST500. This motor is designed for wider than standard 150mm drop-outs and puts out a (claimed) 42Nm of torque. Just like its sibling, the rear wheel can be easily removed by using an 8mm Allen key.

As with the other model, the bearings are sealed and 100% watertight, meaning you can get away with a bit of mud-plugging – commuting to work in typical British weather shouldn’t be a problem.

rockrider e-st100 250w rear hub motor

One noticeable difference is the absence of a torque-sensing pedal assist. The E-ST100 uses a more basic cadence sensor, meaning that electric assist is delivered according to the rotation of the pedals.

This pedal-assist system isn’t as fluid and intuitive as torque sensing,  but it may suit some riders better. Torque sensors rely on a certain amount of force being applied to the pedals to produce assistance, whereas with a cadence system, you just spin the pedals and away you go!

What this means in real terms is probably slightly reduced efficiency, and although I prefer torque sensing, cadence sensing systems are okay, although they are not as smooth.


Just like other e-bikes in the range the LCD is neatly mounted by the left-hand grip, allowing easy access to the controls without having to move your hand.

rockrider e-st100 lcd display

The functionality is similar to the other model although the absence of a USB charging port is a little disappointing.  Everything else remains the same and you have access to the following functions:

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

The levels of assistance are as follows:

  • Mode 0 (no assist)
  • Mode 1 (20 – 100 W) – the most economical assist mode will give you the greatest battery range
  • Mode 2 (80 – 175 W) – this mode will give you a meaningful push when the incline steepens, and hustle you along at 15.5 mph (25 km/h) effortlessly on the flat.
  • Mode 3 (150 – 250 W) – level 3 is where things start to happen. For maximum battery range, you should only use this level when you need to. It’s perfect for helping you up steeper climbs and off-road riding.


Externally the battery looks the same as the more expensive model, but it has a slightly lower energy capacity of 378Wh (36v 10.5Ah). Thankfully this battery pack uses high-quality Samsung SDI lithium cells which should ensure decent reliability and battery longevity.

rockrider e-st100 378 watt hour battery pack

Battery range should be in the region of between 30-50 miles – this will depend on a number of factors including rider weight, the kind of terrain ridden on and of course, how much assistance you use.

Buy Now: Rockrider E-ST100 from Decathlon UK

Buy Now: Rockrider E-ST100 from Decathlon Spain

Bike components

Budget electric mountain bikes usually have budget components fitted, but in the case of the Rockrider E-ST100, there has been a good compromise. All the components are tried, and tested and work very well considering the price.


Once again, Decathlon has been spot-on with their choice of gearing. It’s quite common to see big front chainrings and 6-speed freewheels on electric mountain bikes at this price, but not on the E-ST100.

rockrider e-st100 33 tooth front chain ring

Considering the bargain-basement price, the drivetrain has been well thought-out – A single 33t chainring (with ChainFlow 3D anti-slip technology to prevent chain derailment) in combination with a Microshift 11-34 8-speed rear cassette. All are controlled with a Microshift TS39 trigger shifter, M25 long-cage rear derailleur and finished off with a decent KMC Z7 chain.

For the Shimano snobs out there, I have used many bikes (including Decathlon) that use Microshift gearing and I have always found their components to be just as effective as Shimano or SRAM.


Mechanical disc brakes are to be expected at this price point, and the Tektro TDK68 callipers with 180mm rotors don’t do a bad job at all. Sure, they lack the bite and modulation of hydraulic brakes, but they are effective enough for your average day-to-day rider. They’re easy to adjust, and if maintained correctly provide reliable braking.

Wheels and Tyres

One thing you wouldn’t expect to find on a budget electric mountain bike is tubeless-ready rims, but sure enough, the Rockrider E-ST100 has them. All you will need are tubeless tyres, Presta valves and sealant and you’re good to go.

rockrider e-st100 suntour xcr 30 front forks

The 27.5″ rim has 28 spokes up front with 36 at the rear (to cope with the extra weight and torque of the motor). These are wide rims at 23mm and will readily accept tyres up to 2.5″ wide.

Decathlon branded 27.5″ x 2.2″ all-terrain tyres are fitted as standard. I’m not sure if these offer any level of puncture resistance, but I would be inclined to go tubeless if your budget allows it.

Front Suspension

Suntour XCR 30 forks with 100mm travel will provide more than enough shock absorption for all but the most adventurous of riders.

rockrider e-st500 suntour xcr front suspension

These forks are fairly entry-level, but in the greater scheme of things, a lot of bikes at this price have the inferior Suntour XCT forks fitted.  At least these can handle a reasonable amount of abuse – just be aware of their limits.

Finishing Kit

I’ve owned a few Decathlon bikes, and their finishing kit is always decent enough for the price. The E-ST100 is no exception and has 720mm wide handlebars, with ergonomic grips, a 31.6mm seatpost and an Ergofit Evo saddle – I have ridden their bikes with this saddle and in my opinion it’s comfy enough, although saddle preference is a personal choice and you’ll probably want to change it for one more suited to your behind.


Made from lightweight 6061 alloys with hydroformed tubes and the same low frame geometry as the E-ST500, the E-ST100 is going to please most entry-level e-MTB riders. The frame isn’t bad at all and considering the price, I would go as far as to say that it’s the best available on an electric mountain bike for under £800.

rockrider e-st100 electric mountain bike

Who is the Rockrider E-ST100 bike aimed at?

The Rockrider E-ST100 is most definitely aimed at the budget-conscious rider, who still wants something half-decent that isn’t going to fall to bits after a few miles.

This bike is going to be equally at home riding canal towpaths, bridleways, country back lanes and city streets. That’s the great thing about these bikes. They’re designed to be versatile.

An interesting fact is, a lot of electric mountain bikes that are sold, don’t go anywhere near a trail. Most are used simply because of the extra comfort and durability afforded by the high-volume tyres and front suspension.

I can see the E-ST100 being very popular with commuters. Especially with mudguards and a pannier rack fitted.



Ah well… another Decathlon electric bike that offers excellent value for money. But what’s the catch? Well, as far as I can make out there really isn’t one. I know quite a few satisfied owners of Rockrider e-bikes and I’ve ridden a few myself and they never fail to please.

Sure, if you look through the customer reviews and forums, you will come across reliability issues. I know the first model E-ST500 had some problems, and I know there have been some issues with other models. But on the whole, these e-bikes consistently get decent customer reviews.

rockrider e-st100 electric mountain bike review

If you go and buy one of these bikes and then go thundering down the side of a mountain, then you’re asking for trouble. You need to spend well over two grand before you start to get into the realms of really capable off-road machines.

The Rockrider E-ST100 is designed to be an affordable and versatile everyday bike, that can also be used on unpaved surfaces. Is it a true mountain bike? No – it’s fine for some light off-road riding, but try any silly stuff and you’ll be disappointed.

Final thoughts

For the price the Decathlon Rockrider E-ST100 is excellent. It has a decent enough motor, the battery range is respectable and all the components come together to form what is basically a very good package.

If a friend came to me asking for a recommendation of what electric mountain bike to buy for under £800, it would be a no-brainer. The Decathlon bike is about as good as it gets at this price.

A big thumbs up all the way – happy riding!

Buy Now: Rockrider E-ST100 from Decathlon UK

Buy Now: Rockrider E-ST100 from Decathlon Spain

If you own a Rockrider E-ST100 and would like to leave some comments and a review below, please feel free to do so.

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  1. za te novce dobar bicikl,imam ga 1 godinu i prešao 1500km bez kvarova a vozim se po mješovitom terenu.

  2. EST-100 kupio sam ove god, do sada je vožnja bez problema, jako dobro vuče na uzbrdicama s obzirom na moju težinu od 105kg. Domet baterije s obzirom na moju težinu je jako dobar oko 60 km ,uglavnom 1 stupanj jako malo 2, uglavnom vozim u 7 ili 8 stupnju prijenosa. Uglavnom sviđa mi se robusnost izrade i mogu samo reći da obzirom na cijenu da je jako dobar izbor.

  3. I have owned the Rockrider E-ST100 since January of this year 2021.
    I commuted to work from Feb to end March doing 25 miles per day.
    If you keep the assistance at 2 you get very good mileage with battery and power to spare.
    In mode 3 you get quite a bit of torque from standing so pretty nice to have.
    Bike has performed with no faults whatsoever but after 500 miles had to put a new chain as got quite noisy. Other than that reliable as a dream.
    Hub motor for a commute again much preferred as fully sealed and no issues with water getting in.
    If you were to break a chain you can still get home by just turning the cranks due to the cadence sensor or as with a mid drive you could be stuck on foot 10 miles from home.
    Couple things could be little better namely brakes you have to pull the lever fairly hard but still performs fine and doesn’t have the feel of hydraulics of course.
    Lastly the fork has very little travel to be honest but as a commuter bike you cannot go wrong.
    Also if you have a fairly large commute i would personally go with a cadence sensor bike as i don’t particularly want to be knackered before getting to work where a torque sensor you have to put in effort.
    I would recommend the bike to anyone especially at this price point with an elegant frame and decent components which have proved to be reliable in my case.

  4. Does anyone know if there’s a pannier rack that will fit this bike? I got one from decathlon but it doesnt even fit flush on the seatstay lugs, I would have to bend the bit the screw goes through to try make it work

  5. Thanks for the review, there are very few for the Rockrider E-ST 100.

    I know that the official specs say the forks are “Suntour XCR 30 with 100mm travel”, but all the pictures of this bike show XCT, without the lockout option (your only picture with the XCR marking is of a different color bike with 120mm travel). I also can’t find that fork on the Suntour site for 27.5″ wheels.
    Did they update the E-ST 100 and not the photos, or are the specs wrong?

    The forks on the E-ST 500 are indeed XCR with 120mm travel and they also allow lockout. If the 500 had the option to switch between torque sensor and a cadence sensor it would be a must-buy for me. But I think my bad knees won’t like the torque-only assistance control.

    On the other hand, I find the E-ST 100 too low-spec (mainly the fork) for what I want to do: some commuting but also some mountain trails and forest roads. Changing the fork adds to the cost, and you still have lower-spec brakes, battery and gearing.

    Looking at the more expensive electric Rockrider models they look like torque sensor only. So there’s very little hope for an E-ST 500 V3 with an additional cadence sensor.

    1. Hi Dan,

      It’s been a while since I tested the E-ST100, but I’m fairly sure it had the XCR forks fitted with the lockout on the top of the stanchion. I would contact Decathlon directly to double check the specification as it’s quite possible the model I tried out has a different spec to what is available now. Although I’ve just had a quick look on their website and they are still listing the XCR30 in the spec list.

      The Rockrider E-ST500 uses a combination of torque and cadence sensing to produce pedal assist, it’s still very responsive to pedalling input, but does require a certain amount of force in order to produce assist.

      Another option worth considering is buying a reasonable specification hardtail MTB and fitting an e-bike conversion kit like a Bafang BBS01B 250w, you can build a bike with a fairly good spec for under £1000. The Bafang motor uses a cadence sensor and you can re-configure the pedal assist settings easily using a laptop and USB lead (to suit your particular needs).

      If you need any more info, please let know.


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