The Protos is the marquee frameset from the venerated Italian builder. This latest iteration is beyond anything De Rosa has made before-in over sixty years of building--and the kind of bike that influences an industry.
De Rosa has always had a reputation for making stage race bikes, stable, comfortable rides that you can ride all day every day for three weeks, and keep on going. The comfort is important because the less the bike beats you up, the fresher you are as the kilometers tick on. Here, the challenge was to decrease weight, increase stiffness and increase comfort while keeping to the kind of ride De Rosa is known for. The bike has a short front-center with a lower than common bottom bracket for fast steering and stability, making it at home whether it’s a tight crit or a hors category gran fondo.
The weight is 860g for a 50cm frame. Keeping the weight low was important, but not at the cost of comfort, stiffness, or ride.
Every aspect of the frameset works toward that goal. The fork, the design of which translates into “flat face fork,” is as awkward a moniker as the fork is comfortable. De Rosa has been testing various fork designs forever, and reached into their drawer of old steel forks to realize that in steel, the flat crown design had great vibration-damping characteristics. They decided to adapt the concept to carbon-fiber, and the result is great. The wider leg stance is stiff, and vibrations die at the crown. Both greater comfort and greater stiffness achieved. Keeping the stiffness going into the frame is the tapered steerer. It starts as 1 ¼” at the bottom and then tapers to 1 1/8” at the top for ease of stem selection.
One of the things about carbon-fiber fabrication is you can’t see how the material is put together, only the shape. De Rosa goes with a big, boxy, aero down tube for rigidity. What you can’t see is that the middle has much thinner walls, than the ends. De Rosa mixes three different plies of carbon fiber, with the stronger, stiffer stuff at the tubing junctures, and the more pliant fibers in the middle. This provides rigidity where you need it, and flex where you need it. The top and seat tubes are more obviously shaped, with the seat tube starting at the bottom bracket larger and more triangulated both for stiffness and aerodynamics (hiding the rear wheel), and reducing in size and shape to be rounder as it reaches up to the top tube junction. The top tube is flattened, with a flatter top and rounder bottom to better flex with the bumps.
The rear end has what De Rosa calls their Harmonic Dampening System. They start with oversized chainstays. Massive at the bottom bracket, and slimming somewhat en route to the dropouts. Then the seat stays, start thick, and dramatically flatten and taper up past the brake bridge, before getting a little larger right before they join with the top tube. The design is intended to kill vibrations before they encounter the seat post, which is why the stays attach to the top tube. Drivetrain efficiency and road comfort are achieved.
While making the frame more aerodynamically efficient was not a primary design goal of this Protos, De Rosa still found ways to work it in. The fork blades are narrow and even the tips do not break from the aero lines, as they are carved into the blades. The fork crown smoothly integrates with the head tube. The head tube is shaped to direct air slightly downwards-that is aiming it more for the middle of the seat tube, where the aero shaping shrouds the rear wheel. This is to keep the air away from the underside of the top tube, where rider knees typically nearly graze the edges. Keeping air in the space just above the bottle means it has a smoother trip towards the back of the bike. The downtube flows into the lower seat tube and chainstays for similar aero advantages without detracting from ride quality.
The Protos comes as a frame, fork, and seatpost clamp. You supply the headset. The Protos takes a 31.6mm seatpost. The bottom bracket standard is BB86. Cable runs are internal, and you can choose to switch from mechanical to electronic and vice versa. The cable entry ports come with plugs. If you go electronic, you can run the battery, be it Shimano Di2 or Campagnolo EPS, internally. As this builds into a stage race bike, De Rosa has designed clearance for up to 28mm wide tires. A chain catcher is recommended for the front derailleur hanger, as clearances are tight between the crank and frame.
The De Rosa Protos is topo di gama, over the top. Which is exactly what De Rosa wants for you.

De Rosa Protos Frameset

47cm

50cm

52cm

RRP	(4 293 €)
Où acheter	— (1 €) At
Catégorie	Course

Cadre	Carbone
	Carbone
roues
Taille de roue	700c
Autorisation	28c




Transmission
Site de marque

Cadre	Torayca T1100 / T800 and XN60 Carbon Norme BB: BB86/BB92, 86.5mm, Appuyez sur Fit Dégagement des pneus: 28c
Fourche	De Rosa Carbon 1 1/8" - 1 1/4"
Pédalier	BB86.5mm Required
Casque	Integrated 1 1/8" - 1 1/4" Required
Tige de selle	31.6mm Required Type: Rigide