Monday, December 29, 2008

Carbon Kouign Amann (Speculos Evolution 1)

Second day of testing. Geoffroy is much faster than yesterday. I gave up following him with my mountain bike and watched him turn and turn around the block. A smile on his face says it all, the bike is well born.

Geoffroy was the first one to test the bike. He is a front drive beginner but managed to ride without any problem. The front end is lighter and easier to steer and Marc's steel bike as expected. The balance seem good and it feels faster than a VK2 according to the rider. Well the bike weighs about 6.8Kg complete and that could explain the good up-hill speed also.
The frame behaves well on bad road and the back end looks a bit too stiff but it might just be a visual effect from the large seat.

07/02/09 If Batman had a bike, it would certainly look like that: I will now start the paint job and I have a surprise for my friend Black adder. The steering clamping system is not final. The frame feels stiff enough. This bike can be a SUB 7 with a lighter crank. My next bike which will be an evolution of this one should be much lighter. :) 27/01/09 The Shimano bar end shifters have been fitted. The 4th gear was missing so we decided to open it. Well that was a bad idea, it took 5 minute to open it and about 2H to reassemble it. The first spring was tricky to fit. It really looks like a Swiss watch inside. I am not convinced they need that many seal and gasket. Never mine! I also fitted a set of Tecktro levers. They are fitted facing backwards on purpose to keep the cable as long as possible in the handle bar. The crank has been drill at 150mm. The ends will be reduced later. This baby weight a tonne! I just bought a Broken stronglight carbon crank and I will try to reduce it soon. 16-01-09 The seat has been bonded to the frame so as the bottom bracket. I now need to reduce the crank length from 170mm to 150mm. 5th January 2009 The seat and handle bar need ajusting on the frame. The seat will be bonded on the frame to improve the side stiffness of the frame and save a bit of weight. The drawback is that it is impossible to adjust the bottom bracket length. Hope it will be OK.... The stem is now built and taped to the U handle bar. The stem is longer than necessary and will be trimmed to fit the rider's position. The handle bar is now fully covered with carbon. At this stage is weighs about 200g. It really looks like a Batman boomrang. The handle bar is made in a piece of foam and covered with two layers of carbon (300g at 0/90 and 400g at +/-45). The tubes are made over a PVC tube but this is not very accurate as the overlap creates a bump. A female mould would be a better idea to get the 22mm diameter. 29 December 2008 A friend of mine (Gilles) has decided to build a similar bike and he has started by a 3D drawing of the bike and it is a good exemple to show how accurate drawing can help to spot problems. The 'BEAST' is on wheels. I still need to increase the cut-outs in order to make the bike look lighter. I am now waiting for the bearings to arrive for the US and for the seat + handle bar drawings. The bike should be ready in a fortnight and I hope that stiffness will be ok. The front part of the frame has been built in a few hit. A male foam mould has been used to give the basic shape then volume has been added to increase stiffness. This might not be necessary but for the first frame it is safer. The next stage is to build the head tube with a female mould and a bladder. Well this is not easy and the result is 'just' acceptable because the bladder lost pressure. The front of the frame should weigh about 1.2Kg with paint. The rear frame is now complete and weighs 900g so it should be around 1.1Kg after painting. I made a carbon tube 1"1/8 to fit the headset bearings. I tried to keep the frame very narrow (35mm) between the legs because it can be painful if your legs wear on it for a long time. The back of the frame is built with my usaul method: foam core + carbon socks. I made a groove in the foam to fit a 9mm plastic tube to hide the rear brake cable. I am back on track for this new bike. The frame has been designed full scale on a sheet of MDF and I realised that the chain would not fit if the frame was to be built like my sketch. A clear film has been used to sketch possible modifications and improvements. A V-brake should fit the tight space between the crank arms. Chris King bearing will be used. I tried to enclose the wheel in the frame so it will be easy to fully fair the wheel for racing. Laurent Dechenne came last week to finalise the next bike for Marc Lesourd (Vipère). Marc is currently riding a 'speculos' made of steel by Laurent and this type of bike proved to be very very fast up-hill compared to a Baron so we decided to make a carbon version to give Marc an Edge for next year. The bike currently weighs about 12-13Kg and we should be able to make a much lighter bike at around 7.5Kg to 8Kg. Here is the result: Light weight carbon frame, semi faired front wheel, airfoild U handbar. The chainset will be enclosed in a box if we can. This drawing was produced about 3 years ago to show what could be done in carbone. The bike geometry was wrong but it opened a long discussion with Laurent Deschenne and a metal prototype was built.


Anonymous Anonymous said...

Dear Malric,

Warm greetings to you and Happy New Year 2009 from Malaysia!

I've just stumbled upon your blog site whilst searching in Google for carbon low racer...and I'm very impressed by your current project of building this new low racer!

I'm one of the first few who started recumbent hobby/part-time business 3 years back. It's been a really small market here as recumbent is still very new..and only a handful are keen to own them as touring bikes. However, this year...I'm planning to introduce recumbent as a fast machine...and thought about low racer..and yours seems to be a very innovative design.

Perhaps we might have a business opportunity together in the near future.

Looking forward to hearing fom you soon!

Thank you very much for your kind attention.

PS - do check out my humble webpage at (

Email :

7:30 AM  
Blogger luisfranz said...


Great bike!!!
Your blog is very interesting!!
I visit your blog every day!!

best regards!!


9:56 PM  
Blogger Speedy said...

Thank you. I hope my blog will help you to build your own bikes or something else.

10:18 PM  
Anonymous Anonymous said...

Dear Malric,

"The back of the frame is built with my usaul method: foam core + carbon socks"

Shall I understand that the foam is enclosed inside the frame once the carbon socks are bonded : the finished frame = foam + carbon + resin ?

What do you think of this building method : 2 halves bonded (see exemple 1 et exemple 2) ?

Kind regards,

Odysseus (forum Jaune)

9:42 PM  
Blogger Speedy said...

to Odysseus
Yes, the carbon socks cover the foam core. the foam stays inside and contributes to the global section stability to avoid skin buckling.
Jim 's method is time consuming and I can't see the point of doing it that way.

5:56 PM  
Anonymous Anonymous said...

Weight ?!

10:19 PM  
Blogger Speedy said...

I think this bike will be under 7.5Kg complete. I should have the answer pretty soon.

6:10 PM  
Anonymous Anonymous said...

Greetings from Finland!

I am very impressed by your current project of building this new "speculoos" low racer!

Maybe i built one for me... , but i have no experience on carbon work. And meny children... no time.

How meny euros do i have to pay to you to have one of that kind a recumbent? is it even possible?

Or is it ok to ask info from you if i need to have some advice whit details.


11:05 AM  
Blogger Buckyllama said...


I've been following your blog for some time. Your work is beautiful and I am particularly impressed with this latest effort.

I was wondering if you could share some specific information about the geometry of the final design as well as the layup schedule you used for various parts of the frame. I'm also a homebuilder looking to make the jump into carbon and something similar to this bike is very tempting.

I'm also looking forward to hearing your impressions of riding it. Specifically I'd like to hear how it compares to your existing low racers as far as climbing, comfort, handling etc are concerned.


9:54 PM  
Blogger Speedy said...

To Juka: I sent you an e-mail.
To Tim: My latest bike has more or less the same geometry (55deg steering angle).
If you have never built any composite parts then you should try building a seat. It is a lot easier than a frame. I am sorry, I can't share any information about the number of layers because it would involve my responsability if you crash. If you build a complete frame at 1.6Kg then you are on the safe side. Below that, you need experience.
A friend is coming tomorrow to test the bike. I will post a few information about it this WE probably.

12:25 AM  
Blogger Buckyllama said...


Thanks for the info. I have done some composite work in the past and I did a seat for my homebuilt hiracer last year. (all glass to date though). I am planning on putting together a better set of seat molds and producing seats in carbon before starting on any frame work.

I completely understand about the liability issue but I do have one theoretical question if you feel comfortable answering it. (If not, again, I completely understand)

How important do you feel 90deg fibers are (perpendicular to the tube) when using a foam core? Their primary function in a hollow tube is to prevent a torsional collapse, but the core also has some effect there.

The reason I ask is I am putting together a set of samples to destructively test in order to quantify fiber orientation characteristics. But carbon is expensive, so any expert advice may result in testing fewer samples.


6:34 PM  
Blogger Speedy said...

Hi Tim,
The 90deg fibre to good to prevent skin buckling but it is not necessary when using a foam core.
I only place a 90deg patch (100 x 100mm) on the frame near the front end of the seat where the curve is important and where the carbon is in compression because the carbon in compression can create a huge crushing pressure on the foam core du to the curvature (like a curved bridge, the radius wants to be tighter and tighter) Is it clear?

Working with carbone is similar to glass so you won't have any problem. Use sating woven carbon 300g/m2 maximum with no bonding powder. That way you can curve the carbon on the foam former. Place fibers at 0deg and +/-45deg.
You need to paint your foam core with a resin/silica gel mix to form a 'hard skin' on the foam and create a bonding surface. Epoxy resin does not stick well on Extruded polystyren.

If you ever build a bike, post me a picture.
Good luck.

12:10 AM  
Anonymous Anonymous said...

I like it!

I was wondering if the handlebar style is personal preference or something that the geometry demands.

Would it work well (be controllable) with tiller steering?

7:17 AM  
Blogger Speedy said...

I left the fork tube long enough to fit a conventional racing hand bar to check what is best.
A large U bar, provides a much better steering control in corners than a tiller. The drag penalty is minimum if the rider can keep his arms straight.

10:27 PM  
Blogger Recumbent Guy said...

Hi Malric,

A really beautiful design on the Kouign Amann! I had a couple of questions on the front end.

1. how is the BB mounted in the nose? Looks like a hole had to be drilled. Is is a Titanium BB to prevent corrosion?

2. Are the dropout holes in the CF simply drilled though or is there any special reinforcement needed?

3. On the Zockra website, it says the bikes are made with prepreg with airbladders in a mold. The pictures for the Kouign show a layup over foam core. Did the production bike using the prepreg/airbladder approach?

Thanks for any help you can provide!

12:45 AM  
Blogger Unknown said...

Hi Malric,

I will make a trike bike .
I do have a question about how many carbon socks did you need.
i dont find any of thad. No wone speek about how many layers .
Please tell my :)

Regards. And thank for you help
from belguim

9:34 AM  
Blogger Speedy said...

To Cycleguy:
1- The aluminium BB is brushed with Epoxy adhesive then wrapped in fiberglass. The BB is then bonded in the frame. The foam core is removed just at the entrance of the hole to make a internal fillet of filed resin. Then the BB is taped outside with a couple of layers of carbon.
2- In way of axle, the frame is solid carbon QI et just drilled. Metal insert would probably be better.
3- Prototypes are made over foam formers. Production is bladder moulded.

To Chris:
You can buy carbon socks with fibers à +/-45deg and UD socks. You can't only use fibers at +/-45deg because this is only good for shear and torsional stiffness. UD fibers will give you bending strength and stiffness. Use 50% at 0° and 50% at +/-45°. The number of layers will depend on the section. Small section = more layers. As a frame is stiffness critical, you will feel if the frame needs more layers after the first ride. My advice: never paint the frame before the first ride!
Good luck.

11:39 PM  

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