887g of aerodynamic

Publié le par Adrien

Custom handbuilt wheels have several advantages over serial production wheels. We can adapt the components to the wishes of the rider: for customize the stiffness, the resistance, the inertia, the aesthetics but as well for the "price" and the "weight". The big manufacturers can't combine all these parameters, they rather focus on a balance. Custom wheels offer a multitude of combinations to concentrate on many parameters, sometimes all of them.
Thus, this project nurtured over the technological breakthrough of the spare parts manufacturers.
Today, we are able to assemble a high profile wheelset which is sub 900g. This, with no real concession.



Technical choices
For the speed
To be performant, a wheel must be aero in order to cut the wind and slow us down as least as possible. A high profile rim, a few number of bladed spokes, at least for the front, and hidden nipples are strongly advised.
During a race, a time trial, a cyclosportive or even while training, the rider sit on the saddle most of the time: the wheel stiffness is rarely caugh napping. That's why it is highly recommended to use a low front wheel spoke count. Indeed the front wheel is the most important in term of aero: it enters directly the air flow while the rear one is "protected" by the frame and the pedaling motion of the rider. So we chose 16 spokes at the front and a tiny hub.
Still looking for the lowest drag and maximum speed, the frotn bracing angle was reduced to the minimum: the spokes head face the exterior of the wheel.

For the inertia
For snapping acceleration, the wheels need to be light, or rather, with a low inertia. The rotating mass has to be as low as possible. Light rims and tires are essential. Beside these two components, the spokes nipples contribute to the wheel inertia and have to be made out of a light matertial. They are in aluminium.
Hitting two birds with one stone, the titanium spokes are light and bladed to reduce the inertia and the drag as much as possible!

For the stiffness
As mentionned in the paragraph "for the speed", we favoured the aero instead of the stiffness of the front wheel.
However, the rear wheel features several details, invisible for the novice, which contribute to optimize the lateral and torsionnal stiffness.
First, the hub features a special geometry with a high non drive side bracing angle. The distance between the two flanges is close to 65mm! The spoke tensions of both sides of the wheel are less balanced but the stiffness is improved.
Second, the spokes cross each other but there is no contact. This, for two reasons: titanium spokes hate this and make a strident noise, the spoke angle leaving the hub is far better, it reduces the stress and increases the bracing angle, synonym of stiffness.
Both sides of the wheel are two times crossed. The spokes are almost tangential to the hub which makes an excellent torque transfer.

For the bearing resistance
The bearing resistance is very important in the overall efficiency of the wheel. Here the hubs have very low friction bearings thanks to their single seal facing the exterior of the wheel, where the dust usually enters.
Thus, installed on the bike, the wheels stop spinning after several pendulum motion. However their low inertia doesn't help them for this...
The wheels are equipped with standard steel bearings. 688 for the front and 6803 for the rear.
With ceramic bearings, the efficiency would be even better.



 

The look
The wheels look classic, with their black/grey touches. They will match any bike with no problem. Originnaly, we thought about anodizing the spokes in blue. Finally, the discreet and stealth looking of natural grey titanium spokes is better and give the best looking of the wheels. It won't bring your adversories attention... until the first fatal acceleration!

The components
Front wheel
Rim: Lew Racing PRO-VT1 carbon/boron 16 holes 277g
Hub: Flanged M5 33g
Spokes: Pillar TB Aero 1422 bladed
Nipples: Aluminium hex poly-axis
Poids: 369g

Rear wheel
Rim: Lew Racing PRO-VT1 carbon/boron 20 holes 285g
Hub: Extralite UltraHubs SR 158g
Spokes: Pillar TB Aero 1422 bladed
Nipples: Aluminium hex poly-axis
Weight: 518g



Total: 887g

The price
These wheels are, in the presented version, 2156 euros. Compare to what the most prestigious manufacturers offer...
Extra pictures
Without flash



 
With flash



 

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