Decathlon Rockrider E-ST900

BeBiker

Active member
Aug 26, 2020
700
421
Belgium
...But, the delimiter hack is a must. You can feel the motor stopping you, almost pushing back on you, ...
I first got the Peartune from Ebay ebiketuning.com, don't buy this, it has cheap "breadboard style" connectors. They have stiff cables, don't last in place, and have no water-tightning at all.
I then got the Bikespeed-RS from bikespeed.de, that's what I wanted. Original connectors, 10 minutes work to install.
 

RonnieX

Member
Jul 3, 2020
90
77
Northwest
@BeBiker, on mine, it looks like the left side motor casing is in 2 parts and can be removed without removing the crank (though I’ve not tried it yet!). Did you find this or does the crank need removing?
 

BeBiker

Active member
Aug 26, 2020
700
421
Belgium
I was ready to dismantle everything that was needed, but only that small cover below the crank needs to be removed.
and bolting it on is also easy.
 
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andyjayh

Member
Sep 28, 2020
7
4
Guildford
Just wanted to give my view on this bike after owning for a few months.

I bought one of these for my teenage Daughter so she could enjoy riding we me without worrying about the fitness required for hills. Everyone has their view on this but for me, it's about quality time together. Her passion is horse riding and I only see her once every two weeks, separated from Mother.... With an e-bike we can focus on fun rather than fitness training... anyway, onto the bike...

I looked around for ages at e-bikes and this seemed to be far and away the best value for money with a really good specification right out of the box. I particularly wanted a 1x groupset, quality air fork, plus sized tyres, simple display/control and good range. This was the only bike I could find with those features and more plus at a sub £2K price!

I opted for a size Small but did debate Medium as she is 5'3" and growing. Glad I went for the small as she only just fits the bike! and here is one of my criticisms of it, the standover is very high and can be an issue for less confident riders. Even I don't clear the top tube easily and I'm 6ft! This is probably the biggest concern about the bike and the one I would highlight to potential buyers, make sure it fits with the standover being so high!

Whilst on the Con's of this bike, bottle cage position! Who thought that was a good place to put the bottle cage?!? Next to useless being there, especially if you take into account my previous point regarding standover height.

Tyres are not the best and have zero grip once it starts getting slippy.

I think that is it with the Cons of this bike, pretty short list.

I really like it and more importantly, so does my Daughter. During lockdown we, like everyone else, haven't had many other options to get out as a family and do fun activities. With this bike we have gone out as a family at every given opportunity, and had lots of adventures together. I live near the North Downs and we can access from our house so have plenty to explore right from our doorstep. We also have access to a cottage in the Forest of Dean and been there a few times with the bikes and had many an adventure.

I would class that as a success and this bike has been a major contributor to that.

I'm really surprised with the quality of components you get for your money on this bike, Shimano 1x groupset, Brose motor, 500W battery, 780mm wide bars, good seat, wide rims and 2.8 tyres, tubeless ready (converted mine in just a few minutes).

Only item missing for me is a dropper post, not expected given the price point. Here is my question to anyone who has fitted one, is the frame stealth dropper compatible? Does it route over the motor? Can this be done with the motor in place? I can't find much info on this apart from a mention on the product page to say being 31.6mm, it's compatible with most market dropper posts.
 

BeBiker

Active member
Aug 26, 2020
700
421
Belgium
Hey, I installed a dropper post on mine, in my signature you find the link to the description with pics and article links.
The cable can not stay inside the tubes. You would need to bend too much around motor etc.
 

andyjayh

Member
Sep 28, 2020
7
4
Guildford
Thanks for that, just read your thread. Interesting info in there.

So did you rule out an internal cable options for the dropper? I know my girlfriends Spesh Turbo Levo can run a stealth dropper with the cable running internally over the motor but you have to remove the motor to do it! Wondered if this has the same option?

The other slight disappointment I have with the bike is the forks. I specifically wanted an air fork over the cheap nasty steel coil forks on a lot of budget bikes but the stiction on this fork is awful. It really takes a lot to get it moving in my mind and therefore small bump compliance is going to be terrible. The seals may wear in a little with use but slightly disappointed to be honest.
 

BeBiker

Active member
Aug 26, 2020
700
421
Belgium
I do consider it "not possible" because between seat-tube and motor-block, you have to take a very very sharp bend.
So the mid-cable like mine is an easy option, for a bottom-cable you will have to drill a beautiful hole in the seat-tube.
 

Afc69

Member
Jun 12, 2020
20
1
Aberdeen
See on the control panel of this bike, where you switch on/off, change power setting etc etc, there is what looks like a light switch, but there are no lights on the bike. Is this to allow you to add lights, and have them connected up and powered by the bike battery?

What spec of lights would that be?

Or do you guys just add totally independent lights? Anyone care to detail specific types?
 

BeBiker

Active member
Aug 26, 2020
700
421
Belgium
There is indeed a button for the lights.
I read you can add 6V lights, there are multiple unused 2-pin connectors for it on the motor.
 

DT36

Member
Sep 17, 2020
73
69
S. Wales
Had my e-ST900 now for about 4 months and am really enjoying it. This has opened up so many more routes for me at 52 years of age.
Getting good heart rates over 1 hour rides at around 140bpm, where my old normally aspirated bike was pushing me up into the 170s on some sections. For me, the steady constant HR is more preferable.
Bike is doing everything I need it to and I am certainly not outriding it. Motor is very smooth and quiet.
I've changed the pedals to Race Face Ride and the saddle to an Ergon SM Sport. Other than that, everything else currently remains standard. I have actually purchased a 38T chainring for more winter road riding, but still not got around to fitting it yet.
Definitely a good entry level EMTB and value for money.
 

RonnieX

Member
Jul 3, 2020
90
77
Northwest
Covered 500 miles + on my E-ST900 in 3 months. Just been back to Decathlon for its safety/service check.

I raised 2 issues with them. The rear brake rotor moves side to side in the caliper giving a metallic noise when cornering at speed. This is a recognised fault highlighted in the Decathlon Support page. And, the gears aren't indexing properly! Alas neither of these problems were fixed and, as my nearest store is a 40 mile round trip, it’ll be easier for my Local Bike Shop to sort out the latter. The former I may just have to live with.


following advice from @BeBiker I fitted the Bikespeed RS which has made a world of difference and less than 10 minutes to fit or, if necessary, remove!

I love riding the bike. Others remark, not that its an ebike, but the actual size of it! Its massive compared to a normal hardtail mtb.
 

MPJ

Active member
Nov 28, 2019
151
200
Chiltern Hills, UK
Covered 500 miles + on my E-ST900 in 3 months. Just been back to Decathlon for its safety/service check.

I raised 2 issues with them. The rear brake rotor moves side to side in the caliper giving a metallic noise when cornering at speed. This is a recognised fault highlighted in the Decathlon Support page. And, the gears aren't indexing properly! Alas neither of these problems were fixed and, as my nearest store is a 40 mile round trip, it’ll be easier for my Local Bike Shop to sort out the latter. The former I may just have to live with.


following advice from @BeBiker I fitted the Bikespeed RS which has made a world of difference and less than 10 minutes to fit or, if necessary, remove!

I love riding the bike. Others remark, not that its an ebike, but the actual size of it! Its massive compared to a normal hardtail mtb.
@BeBiker Same rear brake disc issue for me when I had mine. I had a badass box and worked well on the 'private' tarmac sections I rode. Gearing was good up to about 22mph but after that you start to look like a demented paperboy! Great bike (y)
 

Anglosaxon

New Member
Oct 23, 2020
3
8
United Kingdom
Evening all. Have just 'hit the button' on an ST-900 as had an email they were in stock.

Looking forward to receiving it and giving it a try, should be here by 2/11.

Have purchased after reading MANY reviews/thoughts, both here, and the wider cycling world in general, as there doesn't seem to be any bad press about them.

Will report back once I've tried.

Paul
 

andyb2

Active member
Jan 10, 2020
176
251
somerset
As this forum likes expensive parts on cheap decathlon bikes, here's my brother-in-law's EST-900:

20201101_130800.jpg
 

andyb2

Active member
Jan 10, 2020
176
251
somerset
nothing wrong with the original, he just got a good deal on the Trust Message (which at original retail cost more than the bike!)
 

Afc69

Member
Jun 12, 2020
20
1
Aberdeen
Hi, I put my bike to Decathlon on Thursday for its (belated) 3 months service. The bike tech must have over tightened the front wheel hub “pin” as when I attempted to remove the front wheel to get it into my car, I damaged the hub pin with the Allen key and its now totally stuffed. Any ideas how to remove it in order to install a replacement?

7CF539F4-5A1E-4B3B-AAE6-885B30AFFB48.jpeg
 

BeBiker

Active member
Aug 26, 2020
700
421
Belgium
...got a good deal on the Trust Message (which at ...

Seems to bring the disadvantages of a full suspension to the front of a bike too.
 

Afc69

Member
Jun 12, 2020
20
1
Aberdeen
Had my e-ST900 now for about 4 months and am really enjoying it. This has opened up so many more routes for me at 52 years of age.
Getting good heart rates over 1 hour rides at around 140bpm, where my old normally aspirated bike was pushing me up into the 170s on some sections. For me, the steady constant HR is more preferable.
Bike is doing everything I need it to and I am certainly not outriding it. Motor is very smooth and quiet.
I've changed the pedals to Race Face Ride and the saddle to an Ergon SM Sport. Other than that, everything else currently remains standard. I have actually purchased a 38T chainring for more winter road riding, but still not got around to fitting it yet.
Definitely a good entry level EMTB and value for money.
Afc69 you can put a long Alan key from the other side then use a impact gun to shock it to undo.
Thanks, will give that a go, but I’m not sure if I’ve destroyed the whole length of the Alan head.
 

andyb2

Active member
Jan 10, 2020
176
251
somerset

Seems to bring the disadvantages of a full suspension to the front of a bike too.
I said that to him too (Steve900 in this thread), but he knows more about bikes that I ever will, and he likes what he likes!
 

Rockrider900

New Member
Nov 24, 2020
8
2
London
Hi Everyone.
I've had both the E-ST 520 and 900. I had to return the 520 as the chain kept on slipping off the cogs.
The 900 has felt better so far.....

...but, my display doesn't show the correct residual range even when fully charged,
and doesn't change when I use a different power mode or reduce the range enough after I've cycled several miles. Has anyone noticed this too?

The 520 didn't have this issue at all.

thanks
 

Rockrider900

New Member
Nov 24, 2020
8
2
London
Hi Everyone.
I've had both the E-ST 520 and 900. I had to return the 520 as the chain kept on slipping off the cogs.
The 900 has felt better so far.....

...but, my display doesn't show the correct residual range even when fully charged,
and doesn't change when I use a different power mode or reduce the range enough after I've cycled several miles. Has anyone noticed this too?

The 520 didn't have this issue at all.

thanks
Anyone experienced issues with the residual range not updating while cycling? Does the range change when changing the power assistance level?.... please help!!... thanks
 

DT36

Member
Sep 17, 2020
73
69
S. Wales
Anyone experienced issues with the residual range not updating while cycling? Does the range change when changing the power assistance level?.... please help!!... thanks
Can't say I've really looked for this function.
Weather has been absolutely atrocious here in Wales, so not been outdoor cycling much. Most of my riding has been 30 mins a day in the garage on my old Saracen bike perched on a turbo trainer. Also going to fit the pedals from my Rockrider 900 to my Saracen this weekend.
I've just had some DMR Deathgrips arrive this week and will fit them tonight in the hope of getting out this Thursday, as I'm off work and the weather app looks decent with no sideways rain or snow :cool:
If I do get out, I'll try and have a look at the residual range.

DMR Brendog Death Grip MTB Grips.jpg


IMG_20201221_164753.jpg
 
Last edited:

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