- - Colnago K. Zero TIme Trial Bike

Colnago K. Zero TIme Trial Bike

Here’s a closer look at the Colnago K.Zero Time Trial bike. Dig !  



K. Zero 

Bicycle effi­ciency can be sep­a­rated into two key areas. How well the bicy­cle con­verts the power from the rider to power at the rear wheel to drive it for­wards – and how well the bicy­cle resists being slowed down by the air it passes through as it moves. These two things are the deci­sive fac­tors when it comes to effi­ciency. All of our bicy­cles are excep­tion­ally good at turn­ing rider power into rear wheel power, and so the main area in which Colnago could make improve­ments to effi­ciency on a new Time Trial machine was how well it resisted the drag effects of mov­ing through air.

In its most sim­ple terms, aero­dy­namic drag is pro­por­tional to the square of the speed – in other words if you ride along at 20kph, and then increase your speed to 40kph you will expe­ri­ence four time as much drag. So hav­ing a bicy­cle that has a low amount of drag to begin with gives greater ben­e­fits the faster you ride.

But there is a bal­ance to be had with reduc­ing drag on a bicy­cle. We could go too far and make a bicy­cle that no longer rides like a good bike should. And that is what we have been very care­ful of with the cre­ation of the K.Zero. It rides likes a Colnago bicy­cle should, offer­ing com­pro­mise per­for­mance whilst deliv­er­ing increased aero­dy­namic performance.

The main area we have sought to find per­for­mance increases in are the areas that cause air flow over the bicy­cle to be dis­turbed the most. We found that by con­trol­ling the air flow where we needed to, we could bet­ter con­trol the air as it passed over other key areas of the bicy­cle struc­ture. Our research focused upon the han­dle­bar and stem area, the brake sys­tems front and rear, and also the pro­files of the tube sec­tions being used. All of this was done within the tight restric­tions put in place by the UCI – ensur­ing our K.Zero is fully UCI com­pli­ant for com­pe­ti­tion use.

As with any bicy­cle where aero­dy­namic drag is one of the main design con­cerns, it is a mat­ter of mak­ing small reduc­tions in drag over many areas. When all of the small reduc­tions are added together, only then can large ben­e­fits be found. This is one of the mains aspects of the K.Zero – the small details all add up to big benefits.


The brakes are fully inte­grated into the fork and the frame, with­out com­pro­mis­ing the struc­tural integrity of either. With the rear cable fully enclosed to fur­ther reduce the aero­dy­namic drag, the rear brakes are then hid­den with an aero­dy­namic cover which aids the con­di­tion­ing of the air­flow along the under­sides of the chainstays.


The han­dle­bar and stem assem­bly is one bespoke unit. Unlike tra­di­tional bar/stem inter­faces we have cho­sen not to turn the aero­dy­namic pro­file of the bar into a round shape to inte­grate into the stem. Instead, the stem is of the same pro­file shape as the bar. This has led to a stem/bar joint where the stress lev­els are also greatly reduced, allow­ing us to make a light­weight bar and stem sys­tem that is also aero­dy­nam­i­cally supe­rior to a tra­di­tional sys­tem. The clip-on sec­tions can them be tuned in height and reach for rider posi­tion­ing, thus keep­ing the main aero sec­tion of the gars in the opti­mal posi­tion, and within the UCI reg­u­la­tions. Another addi­tional fea­ture of the new stem/bar inter­face is the com­plete inte­gra­tion of the cables required for shift­ing and brak­ing. Again, this leads to small but cru­cially impor­tant drag reduc­tions in one of the key areas of the bicycle.

Tube pro­files

Several NACA derived tube pro­files were tested through­out the design process, again, all within the UCI reg­u­la­tions. It is the use of these pro­files in both stan­dard and mod­i­fied form when viewed as a com­plete sys­tem that form the basis for the K.Zero chas­sis. The design looked at the inter­ac­tion between pro­files as a com­plete sys­tem, and not as indi­vid­ual tube pro­files. This is an area of design flow that has always been a Colnago way of think­ing. A bicy­cle is a com­plete sys­tem, not just indi­vid­ual parts, and as such is has to be designed from the very begin­ning as a com­plete sys­tem where all of the parts work in har­mony to make the end prod­uct the best avail­able in terms of effi­ciency and performance.


K.Zero will be avail­able for every top of the range groupset, being Campagnolo, Shimano or Sram. The same frame will be fully com­pat­i­ble with both elec­tronic and mechan­i­cal versions.


Size Size Sc°
Seat angle Pccs
Seat tube length (centre to centre)
Scs Seat cluster offset Ps
Seat tube length (centre to top) C
Chainstay length P
Effective seat tube length A Front centre Os
Top tube length Hs Tube length O Top tube length (horizontal)    
XS 450 509 77° 576 384 78
S 508 517 77° 594 384 85
M 528 522 77° 597 384 105
L 548 544 77° 621 384 123

Leave a reply
Share on