Rockrider 6.0 Btwin electric mountain bike + brake discs + reinforced fork and two-seater!

[Christophe]

A few months ago I converted a old Rockrider 6.0 Decathlon ATV electric (this model came out in 2004) ... I found it cheap second hand but it really was not well maintained (all cables had to be changed, rear wheel bearing HS. ..)

It is a full suspended model, this is what I wanted as a base but I see that the quality is limited once we switch to electric ... a seller of Decathlon even told me that it was a real shit ... Cool!

It is entirely "homemade", I assembled a motor + regulator with a "homemade" battery (assembled element by element please!) In a beast bicycle bag ... and I replaced the V-Brake pads with discs therefore change the front wheel to a double wall disc wheel.

In addition, I welded a beam on the saddle stem to ... make it two-seater enough to make tandem walks in the cool forest!

Small general photo (painting not yet done, nor taillight, I need to extend the rear beam a bit too because the saddle does not have enough clean inertia ... brief prototype look!):

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Obviously, it is "slightly" less classy than the Trek mountain bike that I rented in Chamonix this summer ... But at 4000 € the trek ... we can say that it cost me 6 to 7 times less. ... Then mine is not finished yet! N / A!

That was for the positive!

First negative point the empty weight is 34 kg! Suffice to say that at 2 we exceed 150 kg ...

But what worries me most is the front fork ...

Indeed, neither the frame nor the fork were provided for the discs, so if it goes well at the rear, the fork seems to me rather weak when I brake, I am afraid that a big emergency braking make it fold and it's the bowl! Logic: the braking torque has been offset at the hub, the fork was not designed for this.

Décathlon tells me that a new fork is not mountable because it is an old system (and a good new fork is 200 € ... so bof what!)

So I would like to study the possibility of strengthening it ... but how?

I can weld what it takes as a profile or shape on it so I thought of putting a 2nd stirrup on the back (triangle) and / or strengthening the front stirrup ... but I fear that this will not be used to great thing because these are the internal fork tubes which deform when braking (I estimate the arrow to be around 10-15 mm at the hub ...).

Then we should not do thermal deformation or embrittlement ... which would make things worse ...

Some pictures of a weak fork.

You will notice the poor general condition, for example, it was missing a fork cap when I bought the bike!

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Side chassis rear wheel it's ok, not even too rusty despite the walks in the forest!

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Edit in 2021, the mountain bike looks like this, hydraulic brakes, two-seater, paint, 3D printed boxes ... etc etc ... : electric-transport / mountain-bike-decathlon-electric-rockrider-3d-printed-battery-box-t16832.html

[Christophe]

Ah, a solution would perhaps be to weld 2 tubes on the back of the fork ... tubes which would fit into each other!

I think of a 12/8 square that would fit into a 16/12 ... the concerns will be lubrication ... and corrosion!

Well the bike already had an Albator look so with that in addition ...

[GuyGadebois]

It's a very low-end bike, you can put all the dressings you want on it, it won't change much. The base is rubbish.

[Christophe]

Not so low-end, it was sold in the 500-600 € in 2004 it seems to me?

But yes it is not top quality level, that yes thank you I knew and that even Decathlon says it ... (which is a little easy once having sold millions ... in short ...) but that remains enough correct for mountain biking ... my level!

I have already thought about changing the chassis but a fully suspended second-hand mountain bike (other than this model), I did not find a chance in my corner under 300 € ... the price of a new mid-range 2019 Decathlon suspension AV ...

So for the moment, I keep this base and I would like to get to the end of the cusomization experience because I have already spent quite a bit of time there. So I just want to strengthen the fork which remains the big weak point!

Note that the original parts preserved are:
a) fork
b) handlebars
c) frame
d) swing arm
e) crankset + derailleur

Custom:
a) Double wall front / rear wheel
b) All sheaths / cables
c) Handles
d) Shock absorber
e) Two-seater beam

So a comment that says the rockrider 6.0 has bad brakes or that the wheels are broken no longer concerns this version!

After yes it remains heavy ... but hey there is a help of the fairy electricity for that!

[GuyGadebois]

If you want, I can sell you cheap this fork which was on an Orbea (diameter of the upper tube 28mm, length 19.5 cm):

[Christophe]

Ah yes it could do it!

Is it compatible with my stem?

Is there fixing for the disc caliper?

[GuyGadebois]

Ah yes it could do it!

Is it compatible with my stem?

Is there fixing for the disc caliper?

There are the clips for the bracket and the diameter of the stem tube is 19.5mm (roughly).

[Christophe]

Cool for the stirrup!

On the other hand I am not at all sure that at the stem level it will be fine ... Are you sure that it is "that" 19,5 mm the stem tube?

On the rockrider 6.0 I measure 38 mm in diameter of the stem (external measurement) ... I will dismount to see how it is fixed (it's been 25 years since I dismantled a stem) ...

I'm not screwed up with finding specific technical info on this bike.

[sicetaitsimple]

I have a solution! Replace the original wheel and brake .....

[Christophe]

Braking is not the problem ...

She is also weak because of potholes and overweight electrification ...