Decathlon Rockrider E-ST900

Gary Davis

Member
Feb 13, 2021
138
79
Belgium
Hi! I bought an E-ST 900 in December but I just started using it because of the weather. Everything is fine, except I also have a noisy rear brake (when cornering at 20+ km/h). What is the correct way to fix? Is this just a simple brake setting (what I will learn on YT :D) ? Or should something be replaced in the store?
Maybe some of you will laugh but I had exactly the same "noise" and I read everything and its opposite until I realized that it appeared around 15,5 mph. It is absolutely not a question of torque. When I "modified" the engine for private areas (of course !) ;), the noise disappeared like a miracle. As this noise resembles a metallic friction, it is believed that it could be the brake caliper but it is an internal noise of the engine related to the limitation to 15,5 mph
 

RonnieX

Member
Jul 3, 2020
90
77
Northwest
Mine is definitely the rear brake rotor connecting with the pads, despite tightened to 20nm.

If you grab the rear wheel and move it with one hand from side to side. You can see the rotor move side to side in the brake calliper. There simply isn’t enough torque!

9 months old and 1850 miles covered, but still does it!
 

Gary Davis

Member
Feb 13, 2021
138
79
Belgium
Mine is definitely the rear brake rotor connecting with the pads, despite tightened to 20nm.

If you grab the rear wheel and move it with one hand from side to side. You can see the rotor move side to side in the brake calliper. There simply isn’t enough torque!

9 months old and 1850 miles covered, but still does it!
Then for those who have formally located the origin of this noise at the caliper it would rather be a manufacturing defect of the hub on which the disc support is mounted. Simply try to mount another wheel with the recommended torque and see
 

Zimmerframe

MUPPET
Subscriber
Jun 12, 2019
14,028
20,817
Brittany, France
If you look at some of the axle heads, they're thicker than others. If you compare the image from @DT36 for the sram one, it has quite a slim head. Where as the one @Chal "modified" ... has quite a thick head. I take it the default one is quite brittle as I stripped the hex head on mine the other day (specialized - same sized axle) and ended up hammering in a t40 torx to get it out.


It might not just be a case of torque. The axle can only go in so far on the receiving end with the thread. Over torquing might pull it in slightly further, 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.

So .. like Gary has said in far less words and far quicker :)
 

DT36

Member
Sep 17, 2020
73
69
S. Wales
Mine is definitely the rear brake rotor connecting with the pads, despite tightened to 20nm.

If you grab the rear wheel and move it with one hand from side to side. You can see the rotor move side to side in the brake calliper. There simply isn’t enough torque!

9 months old and 1850 miles covered, but still does it!
Would a shim work here, maybe?
 

Gary Davis

Member
Feb 13, 2021
138
79
Belgium
If you look at some of the axle heads, they're thicker than others. If you compare the image from @DT36 for the sram one, it has quite a slim head. Where as the one @Chal "modified" ... has quite a thick head. I take it the default one is quite brittle as I stripped the hex head on mine the other day (specialized - same sized axle) and ended up hammering in a t40 torx to get it out.


It might not just be a case of torque. The axle can only go in so far on the receiving end with the thread. Over torquing might pull it in slightly further, 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.

So .. like Gary has said in far less words and far quicker :)
Google translate has become so much my best friend that he can stay at home ?
 

Chal

New Member
Apr 5, 2021
6
4
Hungary
If you look at some of the axle heads, they're thicker than others. If you compare the image from @DT36 for the sram one, it has quite a slim head.

Yes, the original thru axle (Thru Axle Rear Wheel 12x148 mm BOOST Steel) has a larger head. BTW, I think this Sram axle is not compatible because the thread pitch is shorter (1.0 mm vs. 1.5 mm). I finally ordered an original one from Dechathlon, hope to get it tomorrow.

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.

Good idea, I will try it (if the original setup will not be good with the new axle).
 

RonnieX

Member
Jul 3, 2020
90
77
Northwest
I note with interest that the thru axle @Chal linked to (which is unavailable on the UK Decathlon site by the way) is 178mm. Whereas mine is 180mm.

Would 2mm make any difference?
 

Chal

New Member
Apr 5, 2021
6
4
Hungary
I've got the new thru axle today. Thigten it to 20nm, set the caliper, and reverse the rear tire becasue decathlon put it on the wrong direction (and I have not noticed it so far) :D
The metallic noise became quieter but still exist. I think the root cause maybe the big lugs on the Taipan Koloss tires. Isn't it possible that they are resonate the wheel and the brake rotor on asphalt at high speeds?
 

RonnieX

Member
Jul 3, 2020
90
77
Northwest
Thats a good observation @Chal. I changed my tyres for Conti Cross Kings and notice that only when I’m on super smooth tarmac the noise isn't evident. Your theory has some credence. ?
 

Gary Davis

Member
Feb 13, 2021
138
79
Belgium
Hi, So far I didn't have this brake caliper noise problem and hadn't had to remove my rear wheel yet. Yesterday I changed my rear brake. Larger disc and 4 piston caliper. I reassembled everything and tightened my wheel to 11 nm. I went to test it all on the road and I heard this caliper noise but only when cornering. This confirms torsion problem due to tightening torque. Unfortunately, I didn't verify the original tightening torque. I will try to gradually increase the tightening torque, realign caliper and see if there is any improvement.
 

Gary Davis

Member
Feb 13, 2021
138
79
Belgium
Ok. Just tested on the road. A little bit better but I didn't realign the caliper. What I've also noticed is the squeaky, creaky noise when I removed my wheels for the the first time. When I reassemble the front wheel I put some anti seize grease and it's ok. The reason I bring up this is because I think this resistance to tightening (metal/metal)could trick the torque wrench. I realized that after putting some anti seize grease on the axle thread. I was clearly able to rotate the axis further before reaching the recommended tightening torque.
 


Keeprubbersidedown

New Member
Oct 8, 2021
6
0
Sweden
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.
 

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