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With e-bike technology advancing all the time, it was inevitable that some of the more high-tech wizardry would start trickling down to the cheaper end of the scale. Having looked at the new Rockrider E-ST900 electric mountain bike from Decathlon, that trickle is more like a flood! In this review, I will see if this great new E-MTB is too good to be true.
When I first checked out the spec on this bike, I was amazed at what it had to offer at such a low price. Firstly, the Brose ‘T’ mid-drive motor is one of the best on the market.
Specialized have been using the Brose ‘S’ motor on their high-end electric mountain bikes for a couple of years now, and although the ‘T’ version doesn’t produce quite as much torque as the ‘S’ model, it is still nice to see such a good quality motor on a relatively cheap e-bike.
Summary
Decathlon has always designed and produced excellent bikes. Their B’TWIN range has always been popular, but recently they have dropped the B’TWIN moniker from a lot of their bikes.
When I first looked at the specification of the Rockrider E-ST900 and then saw the price, I thought there had been some mistake! I will go into more detail regarding the specification below, but let’s just say it’s remarkable that they have built such a good electric mountain bike and they can sell it at such a great price.
I have ridden and reviewed more electric mountain bikes than I can remember, and nothing has come close to this on price and specification. Usually, you would need to be spending at least £500 more to get a similar specification Giant, Cube or Specialized.
The centrepiece of this bike is the Brose ‘T’ motor. For those of you who are unfamiliar with Brose, they are a German company and the fourth largest family-owned supplier of components for the automotive industry, specialising in electric systems for vehicle doors, seats and electronic systems for steering, brakes, transmissions and engine cooling.
Their Brose e-bike motor is widely regarded as one of the best in the industry and is often seen on high-end electric mountain bikes.
But it doesn’t end there
Not only has the Rockrider E-ST900 got a fantastic motor, but the 36v 14ah (504Wh) Samsung battery should also give a potential real-world range of 80 miles plus.
If the electric components weren’t good enough, there are Rockshox JUDY front forks with 120mm of travel, and the excellent Shimano Deore M6000 1 x 10 groupset, with an 11-42 rear cassette. Tektro TKD 32 hydraulic disc brakes with 180mm discs. And to cap it all off – 27.5″ x 2.8″ tyres on Sunringle DUROC 40 tubeless-ready wheels with thru-axles.
Anyway, I’m going to stop rambling and get on with the specification overview.
👉All sizes in stock now – visit Decathlon here
Features and Tech Specs
Electric Motor
I think Decathlon have proven that they are serious about being a major player in the electric bike industry. Choosing the Brose motor is a wise move. Fitting it to an e-bike at this price point is a game changer!
As I have said previously, the Brose motor is one of the best in the e-bike industry. The ‘S’ version is commonly found on electric mountain bikes in the £4000 plus price range, and the Brose motor is used by over 30 manufacturers worldwide. The Brose ‘T’ motor produces a respectable 75nm of torque, which puts it firmly in Bosch CX and Shimano Steps E7000 territory.
Of course, these motors will produce peak power closer to 400w when in Boost mode, but the top-assisted speed is limited in compliance with European law to 15.5mph.
The motor can provide up to 320% extra assist, thanks to the ‘flex power mode’. The electronic torque sensing pedal assist is one of the most advanced systems currently in use, taking thousands of measurements per second.
When you ride a Brose-powered electric mountain bike, you do feel like you’ve gained superhuman strength!
Not only is the Brose motor powerful, but it is incredibly quiet and efficient. Meaning you can stay on the trails for long, and ride further.
Display
Accompanying the motor is an excellent, compact display, that fits discreetly on the left-hand side of the handlebar. This tells you everything you need to know, including speed, range, battery indicator and power level – Economy, Economy +, standard and boost.
I could rabbit on all day about how great this motor is, but I think by now you get the idea. Let’s move on to the battery.
Battery
The compact battery pack that fits neatly into the frame, uses the excellent Samsung SDI 18650 lithium cells. With a total energy capacity of 504Wh (watt hours), this battery is well above the norm for an e-MTB at this price point.
Combined with the efficiency of the motor, a real-world range of 80 miles should easily be achievable, with a potential range of over 100 miles possible. Of course, if you spend all day hacking around in Boost mode, then you will deplete the battery a lot quicker.
The battery comes with a fast charger, and it can be easily removed using the supplied keys. Lithium batteries should always be charged at comfortable room temperature. In the winter you would want to take the battery indoors to be charged. In warmer weather, it can be charged on the bike.
Gearing
Usually, electric mountain bikes at this price point have fairly entry-level Shimano groupsets fitted – we’re talking Altus, or maybe even Alivio. Decathlon has once again gone above and beyond by fitting Shimano’s excellent Deore M6000 1 x 10 groupset. This includes an M6000 trigger shifter and an excellent Deore Shadow+ rear derailleur.
Up front, there is a perfectly matched 34t Chainflow and anti-slip chainring. With gearing like this, the Rockrider E-ST 900 is aimed at serious off-road riders.
The groupset is finished off with an excellent KMC e10 turbo e-bike-specific chain. This shows good attention to detail on the part of Decathlon, as the Brose motor will put extra demands on the drive-train.
Brakes
The Hydraulic brakes are courtesy of Tektro. The TKD32 brakes, combined with 180mm disc rotors front and rear provide good modulation and a nice amount of bite. They are middle-of-the-road when it comes to overall braking power, but they are more than adequate for a bike of this calibre.
Wheels and Tyres
The Sunringle DUOC 40 27.5″ wheels are tough and have aluminium hubs with sealed bearings. They are 36mm wide, and tubeless-ready, allowing for the extra wide 2.8″ Hutchinson Taipan Koloss tubeless-ready tyres. These tyres will offer a good level of puncture protection, help with traction on steep climbs and inspire confidence when negotiating technical trails.
Thru axles add to the stiffness and robustness required for rigorous off-road riding.
Front Suspension
The RockShox Judy front forks are hydraulic and pneumatic, offering 120mm of travel, plus the usual lock-out and adjustment features. They are fairly entry-level forks as far as Rockshox is concerned, but when you look at other e-MTBs in this price range, they usually use the very basic Suntour XCM forks, which aren’t a patch on these.
As I have previously said, Decathlon wanted a budget mid-drive hardtail, that could be used for proper off-road riding, and not just light trail riding, like a lot of the other electric mountain bikes around this price.
Finishing Kit
All of the finishing kit is high-quality alloy Decathlon branded. And includes the B’TWIN ergofit EVO saddle, which is designed to be more comfortable for long days in the saddle.
The stem can be adjusted for height, and the 720mm alloy handlebars ensure good control when riding off-road.
Frame
The frame has a more relaxed geometry and is made of good quality 6061 alloys with hydroformed tubes. The battery fits very neatly in the frame, and the welds are neat. This bike comes with Decathlon’s lifetime warranty, so you can be confident that it’s going to stand up to the rigours of off-road riding.
Who is the Rockrider E-ST900 aimed at?
This bike is so versatile that it can be used by anyone, from weekend warriors to daily commuters. A pannier rack and mudguards can be easily fitted if required – I think this would make an excellent and comfortable commuter bike. Due to the excellent battery range, it would also make an excellent electric bike for bikepacking helping you on your weekend adventures.
As far as off-road riding is concerned, this bike is more than up to the job. When you look at the alternatives in this price range, it’s easy to see why the Rockrider E-ST 900 beats them hands down, not only on price but also on specification.
I would be confident in taking this e-bike on more challenging trails, and although I do believe it will have its limits, I do think you would have to go some to reach them.
👉All sizes in stock now – visit Decathlon here
Also available online from Decathlon Spain
Conclusion
Well, what can I say? I’ve ridden and tested a lot of e-bikes over the last three years, and nothing has come close to this in terms of value**, performance, battery range and components.
With the Rockrider E-ST900, I think Decathlon has built an excellent electric mountain bike, and made it accessible to a lot more riders.
Previously, if you wanted an e-MTB with this kind of specification, you would be forking out £2000 plus. Here we have an e-bike with all the bells and whistles for nearly £500 less.
For the price, I honestly can’t fault it. I like it so much, I’m tempted to buy one myself! When you compare this side by side with the competition, it becomes obvious that prestigious brands like Cube, Specialized, Trek and Giant can’t come close to this bike in terms of sheer value for money.
👉All sizes in stock now – visit Decathlon here
Also available online from Decathlon Spain
If you are fortunate enough to own one of these, please feel free to leave a comment and review below
Bought this bike some time ago. First of all I was shocked when I saw the size of it’s tires. They are huge! Almost like a fatbike. I didn’t knew that before, because on photos they don’t look so big.
Overall bike feels very good. Motor assistance is amazing, you can go up any hill.
The only ting is that I think it’s gearing is a little too slow. Max speed you can go by pedaling is about 35kmph, more and you have to pedal like crazy. It’s plenty for offroad, but when you go on a beautiful tarmac sometimes you would like to go faster than that. Plus, I found that I mostly use last three speeds, so definitely gearing ration should be bigger. Any ideas is it possible to change the chainring to something bigger than 34 tooth?
Another thing I can’t find any information, is how to connect a light to this system? Tried searching the internet, but the only light I was able to find costs about 2 hundred bucks. That’s outrageous, considering you can order perfectly fine light for 20 bucks directly from China.
Hi,
Thanks for sharing your experiences of the E-ST900 with us.
I’ve just had a quick look on Decathlon’s website and there is a 44t Brose chainring available that looks like it should be a suitable replacement for the existing one. That should sufficiently raise the gearing so you can pedal at 45km/h.
Regarding the lights, I had a look and came up with the same results for Brose (very expensive). You’ll probably be best with a decent set of rechargeable lights and use the USB charging port on the ebike display unit.
All the best,
Tony
I’m considering carrera vulcan e bike or EST 900 Decathlon Rockrider your thoughts on performance of motor and reliability and overall opinion thanks John
Hi John,
Performance wise the E-ST900 beats the Vulcan hands down. The Brose mid-drive puts out about 70Nm or torque vs about 40Nm on the Vulcan Suntour hub motor. The battery on the Decathlon bike also has a higher energy capacity.
As far as reliability is concerned, both bikes have had their fair share of issues. The one that plagues the Carrera is the motor cutting out intermittently, although I know a couple of long-term owners of the Vulcan-E and they’ve never had any issues.
The Brose-T mid-drive motor fitted to the Rockrider is more complex, so there is more to go wrong. Brose motors are generally reliable, but the early generation models suffered from some reliability issues.
If it was my money, I would go for the E-ST900, it’s more powerful and uses higher spec components. It’s also a more capable bike for off-road riding (Rockshox forks, tubless-ready tyres and Shimano Deore 1 x 10). The Carrera Vulcan E used to be quite a good buy, but the price has increased recently and it’s now only £200 less than the Decathlon bike.
If you need any more advice, let me know.
Cheers,
Tony
Thanks for all your advice Tony looks like it will be the one for me go Rockontrail with the Rockrider! Happy trails
No worries, glad to have helped.
All the best,
Tony
Hi guys, I’m looking to purchase the e-st900 as a first ebike. Not sure as to what size I need as according to Decathlons sizing chart, I come in between the medium and large. I am 5ft 10ins in height and have a 32 inch inside leg. Any advice would be welcome as to whether to go for medium or large. Cheers.
Hi Donny,
I’m 6’1 and usually go for a ‘L’ frame, you’ve got the same size inside leg as me, but I’ve got long arms. I currently ride a medium frame road bike without any issues, but I have a longer stem and layback seatpost. I would personally err on the side of caution and go with a medium, at least you can raise the seat and buy a longer stem if it feels a bit too small. If they’re any bike shops open near you it may be worth just trying a medium frame MTB for size to see how it feels.
Cheers,
Tony
Cheers for the advice Tony. The Decathlon store is around 30 miles from my home, but due to the current restrictions are trading online only. I might as well wait till the store fully opens to pay them a visit. Didn’t want to spend all that money I’ve saved since the pubs closed, and find I had ordered the wrong size. Stay safe.
Sounds like the best plan, from what I’ve read most stores should be open by mid-June, so not too long to wait.
Let me know what you decide, and feel free to leave a review here.
Cheers,
Tony
My thoughts exactly about waiting for store to re-open, if my knees get any worse from riding nearly every day i am having one of these. for me from what i have read everywhere is the best value for money end of.
Hi Tony,
Many thanks for your excellent reviews. I currently ride a Carrera Vulcan bike (not electric)
Being a very fit 61 year old this bike has served me well, but recently due to a bad knee I have struggled to keep up with my friend who has an e bike. In particular it’s hard to keep going when riding up hills. I am tempted by your review of the Rockrider E ST900. My question is how does this bike ride with out the assistance of electric power?. I guess it’s not as easy as the Vulcan. If I did buy one, then because of my fitness I would only want to use the minimum of motor assistance. Also how does this bike compare with the Haibike Sduro range.
Hi Pete,
The E-ST900 is a good e-bike, but suffers from the dreaded weight penalty. There’s no discernible pedalling resistance when the motor is switched off, it’s just the extra weight makes the bike feel a bit sluggish (in my opinion).
I’ve been a big fan of Haibike for years, and the big selling point with these bikes is the Yamaha PW-SE motor. As much as I like the Brose-T motor, the Yamaha motor has the edge in my opinion. The only thing with the Haibike is it’s a bit pricier than the Rockrider and has a lower capacity battery and lower-specification drivetrain (9-sp vs 10-sp). The Decathlon bike is hard to beat for the price.
If you need any more advice, please let me know.
All the best,
Tony
Hi Tony,
Thank you for your reply. The Haibike SDURO hard seven 1.0 is approximately the same price as the E-ST900. Am I right in saying the E-ST900 has the better spec, with the exception of the motor?. In your expert opinion which bike out of the two would you choose. Many Thanks
Pete
Hi Pete,
If it was my money, I would go for the E-ST900. The spec is hard to beat for the price. You would need to spend over £2k to get a similar specification Haibike. From a reliability perspective the jury’s still out on the Brose motor. I’ve heard about a few ongoing issues, but the general consensus is it’s a good motor. I’ve been involved with e-bikes for nearly 5 years and the Yamaha motor is still considered to be one of the most reliable.
If you decide to go ahead and purchase the Rockrider, please feel free to share your experiences here.
All the best,
Tony
Are the Haibikes not about £500 more or have they come down?.
Haibike have just released their 2021 models and the cheapest one I’ve seen is the HardNine 4 29er which is about £2000 (if you can find one in the UK). I’ve just had a look on Tredz website and they’ve got a few customer returns going cheap, but frame sizes are limited.
Hi Tony,
On decathlons website it states the motor produces 70nm torque and on giants website it states the Giant Fathom E+3 motor produces 80nm torque, reading one of your earlier replies you stated the giant has 70nm torque and someone stated decathlon informed them the brose t motor produces 90nm, could you clear this up for me as I’m a little confused, thanks
Hi James,
The Giant / Yamaha Syncdrive motor comes in different states of tune. The Syncdrive pro is 80Nm the Fathom E+3 has the Syncdrive sport which is listed at 70Nm. Regarding the E-ST900, I’ve just checked on their website and they are now listing the Rockrider as 70Nm of torque. The magnesium Brose-S model fitted to some Specialized e-MTB’s kicks out 90Nm. Having ridden the Fathom and the Rockrider, there’s not really a lot to differentiate between the two performance wise. Both motors are really good, but in my opinion, the Syncdrive motor just has the edge in terms of overall feel.
I hope this clears things up a little.
Cheers,
Tony
Hi Tony,
I’m looking to buy an electric bike, for both general biking/mountain biking as well as potentially a commute to work. I would say that I am a beginner/ early intermediate Mountain biker.
Thanks for your in-depth review. I had a couple of questions- you say that this would be good for a 30 mile round trip daily commute -which is actually just about the distance between my work and my house. That seems like roughly an hour’s commute each way- I have done it before on a normal mountain bike and it was pretty tiring to say the least! Does an electric bike (and I guess this one in particular) really make that much difference such that it wouldn’t be a slog everyday? Second I can see this bike is £1700-obviously a substantial investment. I can also see that you have reviewed the lower range decathlon electric bikes. For someone who is about to buy their first electric mountain bike do you think it’s worth paying for something like this or to start off with something like the EST100 or 500 v2? Obviously don’t want to miss out if it’s worth upgrading rather than buying a better bike fairly quickly.. For reference, my current (non electric) bike is a £500 rockrider. Thanks for your help! Jon
Hi Jon,
It depends on how hilly your commute is. I personally think the EST500 v2 should be more than adequate for a daily commute with a bit of light off-road riding on the weekend.
If you need a bike that has better gearing and forks for tougher off-road riding the EST900 would be a better bet as the higher torque output of the Brose motor will make it easier to climb steep technical trails, whereas the hub motor will struggle a bit. Decathlon also do the EST520 which is cheaper than the 900, but still uses a Brose mid-drive.
If you’re mechanically-minded I would consider fitting a Bafang mid-drive conversion kit to your existing Rockrider. I’ve converted quite a few in the past and it would work out a fair bit cheaper. Here is an article on building a DIY ebike.
Cheers,
Tony
Great, thanks for your advice Tony.
No worries, glad to help.
Unbelievable bike for the money I really can’t find fault with it on road or off it does the business and battery life is great also,the motor is powerful and smooth with no problems so far after 1000+ miles so glad I bought the Rockrider there are better bikes out there for more money but nothing tops this for value for money I could not be more pleased.
Hi Frank,
Thank you for sharing your experiences of the Rockrider with us, much appreciated. Glad you’re enjoying the bike.
All the best,
Tony
Thanks to your review, I blind purchased the E-ST900 2 weeks ago.
Your review is very thankfully absolutely spot on, as I find the ST900 fantastic, I really love it.
It can really perfectly handle all the trails we go on. I really like the very wide tyres, combined with the awesome motor, makes it feel a touch like my off road motorbike when needed.
The silent motor is so torquey it storms uphill, yet turned down performs perfectly elsewhere.
My only gripes are that the gearing is a touch low on the road (as previous comments). I may try the 44T cog mentioned, but also like the lower gears as they are, for going uphill if I’m not using the electric, so the 44T may not suit.
Also I find the LCD display difficult to read in the daylight, as is a bit dim.
These though are tiny nitpicks on a fantastic bike. A bike that has got a middle aged unfit man, really enjoying riding again.
Thanks again Tony.
Hi Glen,
Thank you for sharing your views on the E-ST900, much appreciated.
I hope you enjoy many happy miles!
All the best,
Tony
How does this compare to the Voodoo Bizango E? similar price at the moment – £1649. I’m new toe bikes and can’t make my mind up between the two.
Cheers
Hi Matt,
The Bizango Halfords have on offer is the 2018 version with the Bosch CX motor and 400Wh battery – great bike, but doesn’t have the battery range of the Rockrider (which has a 504Wh battery). Halfords is handy though, if you have any issues. I’ve ridden both bikes and I personally prefer the Rockrider. If you need any more advice, please let me know.
Cheers,
Tony
I read the statement below in a review on the Decathlon website. Would you like to comment on the question regarding the motor spec. (see below)
…when buying an electric bicycle, check all the components of what it is made up … a lot of information is wrong. The description shows a 90Nm engine and you think you offer money on what is best, but in reality it is a BOSE (T) engine that has only 70Nm …
check the bike components on the manufacturers’ official sites
his note is for those who put in the wrong information, the bike I hope is super.
decathlon service could explain about this situation then i can change my mind …
Decathlon’s reply……….
Thank you for taking the time to review this bike.
May I reassure you that this is a 90NM motor and is exclusive to Rockrider from BROSE. This model is not visible on the BROSE website which understandably may lead to some confusion.
I hope you enjoy this great bike.
Peter, Cycling Manager, DECATHLON
Hi Dave,
Thank you for your comment. According to Decathlon, the firmware on the Brose T motor has been modified specifically for the Rockrider.
Having ridden the E-ST900 and the Gaint Fathom E+3 on the same day, I didn’t really notice much difference between the two bikes (from the e-assist). The Giant uses the Yamaha Sync Drive Pro motor which apparently produces 70Nm. I took both bikes on the same off-road route and I felt the Rockrider performed marginally better – probably due to the 11-42 rear cassette combined with the 34t front chainring vs 11-36 9-speed and 36t front chainring on the Giant.
I would have expected the (alleged) extra 20Nm of torque to be substantially noticeable on the Rockrider, but I felt the performance was more on a par with the Yamaha, Bosch CX. I’ve also ridden the Specialized Levo Comp Carbon which has the Brose ‘S’ motor, and that did feel a bit quicker on steep climbs, but that could be down the the lighter weight of the carbon frame and magnesium motor.
Having said that, I still believe the E-ST900 is the best value e-MTB in its class. When compared with the Cube Acid 400, which is £1699 and uses the 65Nm Bosch Active Plus and 400Wh battery, and the Giant Fathom (which costs £1999).
All the best,
Tony
Thanks for your reply and views.
Dave
Hi Tony Great reviews I’ve read quite a lot of yours and it really helps makes sound judgment.
I am getting back into cycling after 18 years and where I am there is a lot of steep inclines. I recently bought a hard tail but struggled uphill so am looking at e bikes now.
I’m struggling 5o decided between hybrid or MTB?
I will mainly use on weekends for morning cycles on roads and then light trails such as parks and forests with the kids.
I’ve been looking at Lombardo Valderice although found spec to be bit light for the money. I am now looking at Haibike Sduro 1.0 / Rayleigh Motus / Rockrider bit to be honest they all fairly similar.
One of the best value ones I found was the Ampere Explorer
Hi,
Personally I would go for a hybrid unless you’re planning on riding some very rough terrain. A hybrid will ride much better on the road and still be fine for mild to moderate off-road riding.
Depending on your budget there’s a few decent e-bikes in the £1200-£2000 price bracket. I’ve also ridden the Raleigh Motus Step-Thru which is a good all-rounder. The Ampere Explorer looks okay, but the battery capacity is quite low for the price.
Riverside 500 E from Decathlon £1299 – limited stock
Cube Touring Hybrid One 400 £1999
Raleigh Array £1275
I’ve ridden all the above and they’re good value. My favourite is the Cube for comfort and mixed terrain ability.
I hope this helps, if you need any more advice, please let me know.
All the best,
Tony
Compre uma Luz para a bicicleta e.st 900 mas é por usb não da na bik
I am extremely satisfied with this bike. Everything on the review is accurate.
Thank you for your positive comments. I have only test ridden the Rokcrider E-ST900 and it is a great ebike for the money – i’m seriously thinking of buying one for myself!
All the best,
Tony