Thursday, December 3, 2009

Demonchaux Lafayette II Tuned V1 for SALE

Demonchaux Lafayette II Tuned V1 2010

Michelin Jogger 20x1.75 + Nitto B201 AA silver handlebar + ODI grips + Polished brake levers + Sport Tourer Leather saddle
Cromoly frameset + fork
12kg with pedals

Thursday, September 3, 2009

Picture galerie

Just added some pictures of customer bikes into Flickr:

Will keep adding custom bikes as they go out of the shop

Saturday, August 1, 2009

ZR ti fork quick shot

This is how look the Zero Rake Ti fork.
Please note that the frame has been designed for this fork geometry, it is not a standard frame.

Thursday, July 30, 2009

No rake is not straight fork!

No rake fork means 0 mm offset!
The wheel axle is in the same straight line as the head tube.

It is a straight fork, yes! but with no offset!

The steering feeling is different than traditional bicycle forks with offset (tradiotional forks: "straight" or curved forks, they have offset)

No offset fork with adapted frame geometry offer a more accurate steering.
Because the Zero Rake fork wheel axle is not offset, when steering, the wheel stay on the same axle. There is no lateral forces.
A simple way to understand this explanation: Take your bicycle, steer to the left (or the right) and you will see the bike geometry changing as the wheel axis is "offset", the natural thing happening is the bike has to lean toward the opposite side of the wheel direction.

The offset style fork is the current "norm" for two wheelers, but a no rake (no offset) fork with adapted geometry is much more eficient on a bicycle.

The rider has less needs to counter balance his bike when steering it.
Anybody who have climbed a hill road on his bike will know this:

While standing on the pedals, at each stroke of the pedals, the bike is leaned to the left and to the right, the steering mouvement is a suit of zigzags to keep the bike balanced (read: standing)

The Zero Rake concept eliminate the "zigzagging" of the front wheel, which translate as less meters or kilometers depending of the ride! (the shortest road is always straight, right?)
Less distance = more energy saved for faster riding!


I really needs to find a name for this new bike, ZR ti is not that much hugly though I would like something a little bit more poetic

Monday, July 27, 2009

New homepage preview

It took long time to make the new homepage but it is finally coming up!
Here is the new DMCX homepage preview:


Tell me what you think of it, it is still time to change things

Friday, July 24, 2009

What size is 26" by the way ?

Looking through tire maker catalogs it can be confusing to see that there are 26" road tubular and 26" mtb tires but they will not fit each other rims, why?

The so called 26" road tubular tires are indeed 650c size. This means the rim diameter is 571mm

The 26" mtb size has 559mm rim diameter.

It is a 6mm difference between both size and tires will not fit on different type like a 26" mtb tire on a 650c rim, etc...

Thursday, July 16, 2009

Keep moving

The ZR Ti (I really need to find a nicer name for it) concept bike is moving along.

Wheel size, has been decided to be 26" instead of 650c for more practicality.

The brakes will be cantilever type.

Road caliper are made to be light and aerodynamic somehow, but the braking power is not as powerful as Cantilever (or V-brakes)
Cantilever have a kind of "out of date" image since the arrival of MTB as mass market which was fitted with V-brakes and their "more powerful braking"
V-brake are powerful to block the wheel which is pratical for technical off-road riding

Blocking the wheels on a road bike is not practical, we don't want to block the wheel, this is when we lose control of the bike and cannot stop it (this is for this reason ABS is now standard on most cars and some motorbikes)

Well, coming bike to my concept bike.
The braking system will be Cantilver type. It offers best braking modulation with road type brake lever.
Why not Disc brake?
Because disc brake are heavier than rim brakes, also with road bike style brake lever, it is possible to mount only mechanical disc brakes, which are much heavy than hydraulic ones and finally, disc brakes will block the wheels too heasily on steep down hill roads.

Cantilvers are also mounted touring bicycles carrying a lot of weight around the world. This confirm their toughness and reliability.

Finally, the weight/cost performance is also great with Cantilevers compared with road caliper style.

Sunday, July 12, 2009

What bike is it?

It seems there is a market gap.
On 1 side there are Road bikes which comes 99% of the time with 700c wheel size, 650c comes mostly for smaller rider, women or triathlon.
On the other side, there are MTB which comes out in various specific type, most 99% are for off-road use.
Which means mainly with suspension forks and fat (wide section) tires.

There are no bikes made for hilly and mountainous roads on the market.

26" wheel sized "road" bikes are the most efficient bikes on technical roads.

My concept bike is taking me through the whole bicycle culture.
I have to redesign everything from scratch as standard MTB and road bikes are not bicycles aimed for 26" wheel sized Alpine bike.
What should I call this bike category?

Wednesday, July 8, 2009

Fast bike and braking surface

650c has become an exotic size now. It is still used in France but almost disappeared from french shops and suppliers as "randonneuse" and "cyclosportive" had become a kind of antique bikes when the fashion was big swing for the MTB.

It is wiser to make a road bike in 26" than a 650 size almost any store stock this size.
There is a small trend with the 650 randonneuse style but the market is tiny for sport type 650.
Looking at the tires makers catalogs and it is easy to confirm my thoughts.
Almost no tires are available for road use in 650c sizing (650x20 or 23 etc...)
But looking at 26" there is much more choice of width and pattern.

26" Vs 700c
Due to the exotism of the 650c I concetrate my work on the 26" sizing.
Why 26" instead of 700c
26" got advantage for mountains / alpine style road (hey, it is why MTB use this size at the beginning right?)
It is not only goof fit for small rider, it is also more performant for hill climb and and cornering down the roads.
Also, shortest spokes provide stiffer wheels.
And finally, smaller rim diameter and shorter spokes means less weight in rotation.

I noticed several times that while going down Norikura skyline road and other alpine roads at over 100km/h the rear wheel has not much grips when braking hard before cornering.

Mounting 26" offer a choice of high pressure clincher with wider section and still light as 700c clinchers

Tuesday, July 7, 2009

Sunday, July 5, 2009

Demonchaux ZR Ti (Zero Rake) concept

I have been very busy recently with building cromoly frames but the ZR Ti (read: Zero mm Rake offset Ti bike) is the main focus at the shop.
The Beta version should be ready this month.
I'll keep developping the concept