Decathlon Rockrider E-ST900

chamaruco

Inactive Member
Dec 28, 2020
393
329
Arezzo
yes it's true. on my wife's one i have the conti xking and are huge wider but ...you know Size doesn't matter
 

chamaruco

Inactive Member
Dec 28, 2020
393
329
Arezzo
ok, i'm continuing to test this bike on mullet side.
i have to say it is amazing! after few issues due to the switch back to the original 80mm stem now i'm ok with a 60mm one.
i don't feel the bike uncomfortable on the uphill neither unwanted rise of the front wheel.
but what i feel is a great agility and comfort in every conditions. it seems that riding with a 27,5 was the anomaly and now it works as it was born for.
the macroscopic improvement is the absence of that sensation of overturning during hard downhill.
even the fork seems to work better.
IMG_0633.jpeg
FC896304-050C-40A3-87B1-7ED402BC1FBD.jpeg
 
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andyjayh

Member
Sep 28, 2020
7
4
Guildford
Interesting experiment to mullet one of these. They are not exactly the longest reach bike to start with so doing this obviously reduces what you have but you sound like you are ok with that. Rolling the bars forward can help a little rather than sticking a longer stem on there, also making the stem as low as possible.

Personally I like mullet and both my full sus and hardtail are setup this way. The full sus is fully configurable so I can adjust the geometry to suit which wheel size or combo I want but that is unusual. The hardtail is compromised in the same way so I need to adapt and live with the issues but the bike is very long reach in the first place.

Be interesting how you find it over a period of time and if you switch back to compare at all?
 

chamaruco

Inactive Member
Dec 28, 2020
393
329
Arezzo
i did, as you suggest me, last week.. then I was so unhappy that i was returning back to 27,5. when i gave a chance to a stem shorter.
and it is shorter than the stock one. so i don't know if i'm changing the "optimal" or i'm just doing the best assessment for this bike.
 
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Troutwrestler

Member
Dec 25, 2018
136
88
Scotland
Can anyone tell me the actual model of hubs fitted to this bike? All the info says Sun Ringle Duroc wheelset, but I dont think the hubs are actually Sun Ringle.
Does anyone know?
 

IOMTT

Member
Jan 14, 2021
13
5
Brittany
Nice views!
Yes I agree the tyres seem slippery. I was thinking of getting the schwabe smart Sam's for ebikes as an all round tyre.

I'm using the £7 decathlon btwin MTB front mudguards as they fit easily and keep mud and water of at speeds under 18mph... I'm using the topeak defender Rx 27.5 on the rear for full coverage. The front version didn't fit properly on the front unfortunately.

Regarding the residual range, please could you kindly check next time if when you change to a different power mode that the residual range changes to a higher/lower number automatically too?
For me it's strange that your bike showed only a 26 mile residual range at full charge....I would expect it to show more unless it refers to power mode 4.

Thanks
Did you reset the trip?
 

DT36

Member
Sep 17, 2020
73
69
S. Wales
Did you reset the trip?

If this is a question for me, then no I didn't.

Haven't been out in it much lately to tell the truth, as my wife has been on it, while I ride my old normally aspirated Saracen. It's actually dry this week, but the weather is -3 deg at the moment during the day and I think that's in all week.
It's not so much the cold that's keeping me in, but more the black ice that's on the trails and roads.
I'm sticking with my turbo trainer in the warm garage for the time being :)

I will look at this again when we get back out, as I've actually got an E-ST520 getting delivered tomorrow for the wife, so I will be back out on it as some point soon.
 

IOMTT

Member
Jan 14, 2021
13
5
Brittany
If this is a question for me, then no I didn't.

Haven't been out in it much lately to tell the truth, as my wife has been on it, while I ride my old normally aspirated Saracen. It's actually dry this week, but the weather is -3 deg at the moment during the day and I think that's in all week.
It's not so much the cold that's keeping me in, but more the black ice that's on the trails and roads.
I'm sticking with my turbo trainer in the warm garage for the time being :)

I will look at this again when we get back out, as I've actually got an E-ST520 getting delivered tomorrow for the wife, so I will be back out on it as some point soon.
Funnynthat ive got a st900 and my wifes 520 is coming friday.??

did you change the tyres on the 520?
 

DT36

Member
Sep 17, 2020
73
69
S. Wales
Funnynthat ive got a st900 and my wifes 520 is coming friday.??

did you change the tyres on the 520?

Hi, no. The 520 is still on the original tyres (Hutchinson Cougar). These are much smaller than the tyres on your 900.
The rear tyre was facing the wrong way when it arrived, which I was intending to turn around. However, on our first ride out it punctured about 200m from home on our return, so I had no choice but to sort it out. Seems a very thin/light tyre.

For the rides that we are doing at the moment, light trails and cycle paths, these tyres seem to be OK. However, as her riding starts to improve and we start doing more forest trails, I think I'd like to swap them out for tubeless. I fitted a set of Maxxis Ardents to my 900 which are definitely better all round than the original tyres fitted.

Overall, the 520 is very different to the 900 component wise, but seems to be a decent bike so far and is very strong on the hills, or she is a lot fitter than me :)
 

EZ123

Member
Mar 3, 2021
7
7
London
Hi, no. The 520 is still on the original tyres (Hutchinson Cougar). These are much smaller than the tyres on your 900.
The rear tyre was facing the wrong way when it arrived, which I was intending to turn around. However, on our first ride out it punctured about 200m from home on our return, so I had no choice but to sort it out. Seems a very thin/light tyre.

For the rides that we are doing at the moment, light trails and cycle paths, these tyres seem to be OK. However, as her riding starts to improve and we start doing more forest trails, I think I'd like to swap them out for tubeless. I fitted a set of Maxxis Ardents to my 900 which are definitely better all round than the original tyres fitted.

Overall, the 520 is very different to the 900 component wise, but seems to be a decent bike so far and is very strong on the hills, or she is a lot fitter than me :)

Hi, I've had a E-ST520 for a couple of weeks now and picked up a slow puncture on the front. I figured while I was fixing it I'd make them tubeless but your comment about swapping out the Hutchinson Cougars for tubeless made me double take. Are they not able to be made tubeless, and do you need different tyres if you want to remove the tubes. I understand that I need to tape and seal the rims and tyres but thought I could do that with the Cougars..... am I wrong?
 

IOMTT

Member
Jan 14, 2021
13
5
Brittany
Hi, I've had a E-ST520 for a couple of weeks now and picked up a slow puncture on the front. I figured while I was fixing it I'd make them tubeless but your comment about swapping out the Hutchinson Cougars for tubeless made me double take. Are they not able to be made tubeless, and do you need different tyres if you want to remove the tubes. I understand that I need to tape and seal the rims and tyres but thought I could do that with the Cougars..... am I wrong?
I belive the rims are taped already...dont mess around with tubed tyres get tubeless on asap, you will need 2 tubless valves and some liquid sealent. Good luck.
 

EZ123

Member
Mar 3, 2021
7
7
London
I belive the rims are taped already...dont mess around with tubed tyres get tubeless on asap, you will need 2 tubless valves and some liquid sealent. Good luck.
Roger that! Just to by crystal... I can keep the Hutchinson Cougars without tubes?
 

BeBiker

Active member
Aug 26, 2020
700
421
Belgium
Look at some "tubeless ready TLR TL..." mark on the tyres. They exist in both versions.
Besides that, internet says non-tubeless tyres work perfectly as tubeless...

The hardest part of the conversion, in my case, was to get the first time the tyre inflated on the rim.

The first 3 days I had to re-inflate the tyre somewhat, after that it kept the pressure (3bar)
 

Zimmerframe

MUPPET
Subscriber
Jun 12, 2019
14,028
20,818
Brittany, France
Even some tubeless ready tyres seep through the sidewalls sometimes. Though this is normally manufacturing faults. If you're lucky, they seal themselves up and all is well.

As @BeBiker says, sometimes it can be difficult at the start . Getting the tyre to seat correctly with no tube to push it out can be tricky. Sometimes you need to take the valve out so you can get air in faster than it's escaping to push the tyre out to the rim.

Maybe try this first before you put fluid in to get a feel for it before you start splashing sticky fluid everywhere. It's easy to pop one side off the rim to put the fluid in afterwards and at least you know one side is already seated. A compressor is ideal as it will deliver a lot of air very quickly and seat the tyre.

It's a good idea to take the bike for a short ride right after you've done it. This squishes the tyre about and splashes the fluid everywhere, so if there are any tiny rim gaps, tape gaps, tyre holes - these can seal up.
 

Zimmerframe

MUPPET
Subscriber
Jun 12, 2019
14,028
20,818
Brittany, France
Put the new-package-folded-tyre flat on the ground for a day helped a lot too.
After manually re-bending the borders
Sound advice. With some tyres, it's a good idea to mount the tyre first with a tube so it has chance to form correctly.

If it's cold, bring them inside first also so they warm up a bit and are more supple.
 

BeBiker

Active member
Aug 26, 2020
700
421
Belgium
Sound advice. With some tyres, it's a good idea to mount the tyre first with a tube so it has chance to form correctly.
I didn't think of that, I will surely do it that way next time.

I used CO2 cartridges to quickly inflate my tyres onto the rim...
That's 1,5 euro per inflate, I'm much too (avaricious miserly stingy parsimonious ? ) for that :):)
 
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DT36

Member
Sep 17, 2020
73
69
S. Wales
I belive the rims are taped already...dont mess around with tubed tyres get tubeless on asap, you will need 2 tubless valves and some liquid sealent. Good luck.
Rims are already taped up and ready to go.
I'm away from home for the next few days with work, so can't check the tyre. However, I don't think it's a tubeless.
I opted for the Maxxis Ardent in the link below:
 

EZ123

Member
Mar 3, 2021
7
7
London
Rims are already taped up and ready to go.
I'm away from home for the next few days with work, so can't check the tyre. However, I don't think it's a tubeless.
I opted for the Maxxis Ardent in the link below:

That's good to know! Thanks for the info. I'm going to wear the Cougars out then replace them with dedicated tubeless tyres and loose the tubes.
 

Chal

New Member
Apr 5, 2021
6
4
Hungary
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?
 
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Chal

New Member
Apr 5, 2021
6
4
Hungary
So... mission failed:

IMG_5954.JPG


I tried to tighten the axle with a Beta torque wrench two times (don’t ask why, I was just unsure). The second attempt was not tolerated by the axle screw. I think it's my fault, but be careful if you want to tighten it, this screw is very weak.

Now I'm going to search a qualty one. If there is any 12x148mm thru axle you would recommend, I would appreciate it.
 
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DT36

Member
Sep 17, 2020
73
69
S. Wales
So... mission failed:

View attachment 57826

I tried to tighten the axle with a Beta torque wrench two times (don’t ask why, I was just unsure). The second attempt was not tolerated by the axle screw. I think it's my fault, but be careful if you want to tighten it, this screw is very weak.

Now I'm going to search a qualty one. If there is any 12x148mm thru axle you would recommend, I would appreciate it.

Although Decathlon might suggest to tighten it up to 20Nm, it only states 10nm on the axle itself. When buying a new one, I would err on the side of caution and go with the recommended setting.

Link below shows a similar sized axle that will go to 13.5Nm :

I built an engine for a Hill Sprint car last winter and over-torqued the head bolts due to my own error of having a page open for a 1975 year head instead of the later model on the injection heads. Went back to it the next day to do the final stage setting after 24hrs and immediately realised my mistake. Even though they would probably have been ok, I pulled them all back out and replaced with 8 new bolts at about £50. :(
 

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