Decathlon Rockrider E-ST900

BeBiker

Active member
Aug 26, 2020
700
421
Belgium
... but it might be that they made an error and it really needed a 147 axle ? So maybe the answer is to place a 1mm spacer/washer over the axle so it clamps the rear triangle 1mm tighter together when it's tight ? ie, imagine the head is then 1mm thicker along the shaft, so the shaft is then effectively 1mm shorter....
...makes me realize that my noise dissapeared around the time I installed a kids-trailer hinge...
...between bolt and chassis...
...of around 1-2mm thickness...
 

DT36

Member
Sep 17, 2020
73
69
S. Wales
Hello everyone! 1st post here!
What brake pads are you using on your EST900? Do you know alternatives to this A10GS from Decathlon? Here in Sweden they can only be ordered from Decathlon which is terribly slow for anything.
Run a search through Amazon for the pads or Tektro TKD32. You will get a lot of results and prices look reasonable.
 

Azimuth

Member
Oct 14, 2021
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Ok, so I installed the 40t crank.

I had to grind the chain guide a bit to make it fit.

The gear changes are much more "violent" probably due to the more stretched stuff, I have to be more careful.

On plain road the highest gear is still not long/high enough for what I can pedal, but certainly much better than the 34t crank.

20211023_230202.jpg
 

Azimuth

Member
Oct 14, 2021
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A pic with everything in place.

Where can I get the proper tool to unbolt that ring that holds the crank spider in place?

I had unscrew it with a hammer and a screwdriver and it is not a very "clean" way to do it.

( sorry for any wrong terms used, I am not a native English speaker )

IMG-20211023-WA0012.jpeg
 

BeBiker

Active member
Aug 26, 2020
700
421
Belgium
You don't need to unbolt the ring and crank.
With some positioning, puzzling and minor force the 34t chainring comes over, and off.
For those with less experience and precision: cut the useless 34t in half and throw it away.
The 38t, 40t, 42t chainring goes on or off very easy without disassembling anything, that's obvious.
 
Last edited:

BeBiker

Active member
Aug 26, 2020
700
421
Belgium
If your 40t chainring doesn't give enough speed, you can only choose to:
1) put a 42t (big problem when you have chain suck)
2) replace the 11-t cassette with a 10-t (only with expensive microspline hub) (only when also converting to 11speed or 12speed)

A trick used by some is to shorten the pedal cranks.
This will of course not reduce your pedaling frequency (cadance) but it will reduce the pedaling path and rotational mass effect, which gives a similar effect to the cyclist.
 
Last edited:

Azimuth

Member
Oct 14, 2021
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Thanks for the tips, it was my first time doing this, it was not complicated, but I had to take my time. I did not even tried to fit the 40t crank that way since I had already had taken the spider off.

It's ok as is for me, now I just need to fit another kind of tyres and it will do.

Now I would just like to figure out why the controller shuts down the assistance every 15min. I suspect it is some sort of anti hack measure ( which I use for offroad/private use only ).
 

Azimuth

Member
Oct 14, 2021
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For anyone who cares, I just fitted a pair of these ( 27.5x2.00 ):

( edit: can't post links for some reason, anyway, search for schwalbe big ben 27.5x2.00 )

Much better for my needs and if you're like me and need something between an mtb and a road bike, I am happy and I hope it saves you some research time ( If not, well, nevermind ).

20211103_155350.jpg


20211103_155445.jpg
 
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chamaruco

Inactive Member
Dec 28, 2020
393
329
Arezzo
For anyone who cares, I just fitted a pair of these ( 27.5x2.00 ):

( edit: can't post links for some reason, anyway, search for schwalbe big ben 27.5x2.00 )

Much better for my needs and if you're like me and need something between an mtb and a road bike, I am happy and I hope it saves you some research time ( If not, well, nevermind ).

View attachment 75101

View attachment 75102
I hope you can stop this heavy bike with that 180 rotor and tektro brakes
 

Azimuth

Member
Oct 14, 2021
28
20
Required
When you also drive a 30 year old motorbike with 250kg and shitty drum brakes on the back this actually brakes wonderfully and it is very light! I guess everything is relative.
 

Azimuth

Member
Oct 14, 2021
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20
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I did not know they were called Gravel-bikes. :geek: Thanks, I learned something new today.

I assure you I am not hip ( remember, I have a 30 year old motorbike ), it is just a coincidence.

Actually, all my life I prefered bikes that way.

The E-ST900 was a good opportunity to have a less expensive decent electric gravel-bike after a few tweaks.
 

E-MAD MALC

Active member
Subscriber
Nov 16, 2021
406
245
EAST SUSSEX
Evening
I purchased an est900 two weeks ago I will post more on this thread in good time

But people that have the newer Brose control unit

When it come to hacking the speed limiter
You will have problems because they've updated the software

What happens after 500 revolutions of the chainset is the controller kicks out error an code and shuts the electrics down

Anyone had that issue if yo have tried the hack on the latest model

Malc
 

Azimuth

Member
Oct 14, 2021
28
20
Required
Ok, so after suspecting there was some sort of anti-hacking trick in the new units with the Brose controller ( like mine ), making the traditional magnet repositioning trick to stop working after a while, requiring a controller reboot ( apparently 500 revolutions? ), I went ahead and ordered a badass v4.

What I can report so far is that the controller does not shutdown with the badass v4 in place, BUT...

When I am going at about 37kph (gps speed) the controller measures 25km/h, making the speed restriction kick in.

No matter how I reposition the magnet provided with the badass v4, I cannot improve this.

Well, that's better than nothing, but they can't advertise it as a 100% effective solution.

I guess I am done with this "research" for now.

I hope one day eBikes don't come with autopilot too and other junk to take away the fun.

20211216_120323.jpg
 

BeBiker

Active member
Aug 26, 2020
700
421
Belgium
So it looks like your badass is a 1:1.5 pulse devider.

I suspect 1:2 would engage the alarm modus, so they limited the ratio.

With 37.5 or even 32 km/h I would be happy. Mine runs 45-50 km/h at the moment, nobody needs that.

You run 2.00 tyres, mounting 29" wheels could make you win some km/h"s
Road 28" tyres fit perfectly on mtb 29" wheels, look it up, bike manufacturers are crazy.
 
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E-MAD MALC

Active member
Subscriber
Nov 16, 2021
406
245
EAST SUSSEX
Hi there Azimuth
Your still running the old software my friend

It's the 7.4.1 software update that addresses a few issues
See if this link works

I purchase the Bikespeed RS Custom
Which allows me to fine tune the rate of assistance by percentage plus other handy things tucked away from prying if you know what I mean


Well this Xmas I will get round to putting everything I have accumulated over the past four month
Like all of you guys out there I'll give you updates on the progress


Malc
 

E-MAD MALC

Active member
Subscriber
Nov 16, 2021
406
245
EAST SUSSEX
Hi there Azimuth
Your still running the old software my friend

It's the 7.4.1 software update that addresses a few issues
See if this link works

I purchase the Bikespeed RS Custom
Which allows me to fine tune the rate of assistance by percentage plus other handy things tucked away from prying if you know what I mean


Well this Xmas I will get round to putting everything I have accumulated over the past four month
Like all of you guys out there I'll give you updates on the progress


Malc
 

Azimuth

Member
Oct 14, 2021
28
20
Required
So it looks like your badass is a 1:1.5 pulse devider.

I suspect 1:2 would engage the alarm modus, so they limited the ratio.

With 37.5 or even 32 km/h I would be happy. Mine runs 45-50 km/h at the moment, nobody needs that.

You run 2.00 tyres, mounting 29" wheels could make you win some km/h"s
Road 28" tyres fit perfectly on mtb 29" wheels, look it up, bike manufacturers are crazy.

Interesting. Thanks for the advice!

I guess I will stick with this setup for the time being, it is reasonable for me.

I don't want to spend any more money in the bike for now. :whistle:

Hi there Azimuth
Your still running the old software my friend

It's the 7.4.1 software update that addresses a few issues
See if this link works

I purchase the Bikespeed RS Custom
Which allows me to fine tune the rate of assistance by percentage plus other handy things tucked away from prying if you know what I mean


Well this Xmas I will get round to putting everything I have accumulated over the past four month
Like all of you guys out there I'll give you updates on the progress


Malc

Interesting, thanks for the info! :)
 

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