Muenster | Büttgen, Feb 24/25 2020

The rubber hits the road! Track testing gives us our first look at how all the theory and simulation performed in the design stage will work in the real world. Under controlled conditions we can start to understand how close the Kú TF1 gets us to achieving our vision of improved athlete performance.

It is one of the key defining moments in any competition vehicle development, F1 car or bicycle it doesn’t matter, when the engine fires up or the rider clips into the pedals for the first time the heart beats just that little bit faster. Shaking the bugs out and getting that first impression of ‘is it fast?

Triathlon is a unique form of racing against the clock, the triathlete needing to hold position and produce consistent power for hours on end. Every flinch,
every adjustment results in fluctuations of power and aerodynamics costing fractions of time and chipping away at the overall performance.

Now on track we get our first taste of how man and machine respond to each other, how the critical parameters of biomechanics and handling that are impossible to predict from a computer model will interact with aerodynamics to meet our target of total performance stability.

Simply put, how does it feel? is it fast? Asking always, is it fast? To help answer these questions and ease any doubts Kú Cycle partnered with world leading companies in the fields of aerodynamic testing, biomechanics research and handling to measure and optimise the performance of the Kú TF1.



Preparing the test - Sportforum Kaarst - Büttgen - Germany


Preparing the test bike instrumentation

Alphamantis is a field based biomechanical analysis method that allows us to measure one of the key determinants in triathlon performance; aerodynamics.

Bike design and refinements to rider position result in improved aerodynamic efficiency quantifiable in real time using the Alpahmantis Track Aero System (TAS).

The TAS collects a live data stream from the bike and, in combination with the input of environmental parameters of the velodrome, track surface, air pressure, temperature etc calculates the CdA of the bike + rider.

This allows us to measure aerodynamic efficiency of the Kú TF1 and positional variables, in real-world conditions.

Mounting a 3 axis accelerometer
Riders data display
Setting tire pressures
TAS bike mounted data logger and wifi transmitter


Interpretation of results

To be taken with a wide margin of tolerance

Our initial impression of ‘is it fast?’ Yes, yes it is. A confident statement to make after one test but based on good data.

To put that confidence into a deeper context:

Our comprehensive CFD study suggested we could expect CdA numbers close to the gold standard of current Tri bikes, the proof of the pudding on that will be when we finally get in the ring with a P5, but our decision to go from simulation to prototypes based on that study was validated by the results we got in the velodrome.

Now consider the chart below; this shows the steps from a typical athlete aero optimization test.

Starting with some baseline tests the athlete is taken through a logical

development program to refine their position before starting to look at the influence of performance accessories like helmet, clothing and wheels. The test rider’s CdA of 0.28152 places on the table exactly where it would be expected to be based on a great fit, but with no accessory development testing completed.

This is our confidence in the overall test protocols and the results.

The baseline CdA for the Kú TF1 Storm at 0.25641 and the Kú TF1 Lava at 0.26561 showed values equivalent to a fully optimized aero and equipment fit!

With no further optimisation just moving to the Kú TF1 puts you where you might expect to be as a fully optimized elite rider.

Athlete performance delivered.


As those murmurs from the data analysts grew with each new data block it was important to temper our enthusiasm somewhat by appreciating all the elements that place any doubt to the veracity of the results.

When comparing performances, that might be last seasons F1 car to this seasons, or the Stephens Trofeo to theKú TF1 or the Kú TF1 Storm to the Kú TF1Lava, we need to sort the apples from the oranges, at each step accounting for any variables that could be influencing the results.

With the results in, and in deference to those variables and their influence, we could take a stand on where the overall performance of the Kú TF1 lies in comparison to a typical rider optimised to their current ride. Declaring what performance gain they might expect by upgrading to a Kú TF1.

Big difference number one: 3 Different bikes

Big difference number two: 2 Different types of wheels

Big difference number three: Pad reach Kú TF1 Storm vs Kú TF1 Lava*

Big difference number four: Arm pad shape Stevens vs too small on Kú TF1

Big difference number five: Arm pad width Stevens vs too narrow on Kú TF1

Big difference number six: Extension angle not optimised for the test rider

Big difference number seven: Rim brakes on Stephens vs Kú TF1 disc brakes

Big difference number eight: Drivetrain, BB, tires and chain



Effect of shapes on streamlined flow

The greater the cross-sectional area a body presents to the wind, the higher is the air resistance. The second criterion is how smoothly the wind can glide around a certain body shape which is expressed as the familiar Cd value. When these two factors are multiplied together, the result is the air resistance.


Air resistenace is a combination of area and shape

The principle of air resistance resulting from a combination of area and shape holds true when the body shape is a rider on a bicycle. The larger the area the rider presents to the wind, the higher the air resistance and how smoothly the wind can glide around the riders body determines the Cd value.


Forces acting on a bike

Just like an an aeroplane wing that uses the airflow around it to generate lifting forces, the airflow around a rider imparts forces that the rider has to overcome, the greatest of these is the drag force holding them back.



Drag area / CdA

Aerotesting is the ultimate end stage optimization of bike and athlete for improving triathlon performance. By measuring the rider drag we can investigate ways to manipulate airflow and influence the resulting loads with the goal of reduced drag. Performance comes down to Watts (power input of the rider) per coefficient of drag (CdA) and the ability to maintain that power input and aerodynamic position.




Air resistance is a combination of area and shape

Athlete performance is at the core of Kú Cycle and our innovative products help you get you to the finish line faster. Our patented Fork Air Stream Technology (FAST) began like most innovative ideas – by putting pen to paper.

Our chief designer, Richard McAinsh, drew from his prior F1 design experience to reimagine how a fork could be created to reduce the total system drag of the rider and bike.

Using Computational Fluid Dynamics (CFD), he tested early fork shape concepts as three-dimensional models, in a virtual wind tunnel, to evaluate their aerodynamic potential for reduced frame and rider drag.

FAST’s unique shape creates lower overall drag on bike and rider by manipulating and improving downstream airflow control.

After successfully validating FAST in CFD, it was time to bring the product to life. Kú worked with premier manufacturing partners to create our carbon modules, which we cut and bond to your exact speficiations in our factory.

Each FAST is rider specific in length, an industry first, to deliver a rider specific geometry tuned for aero performance. This enables us to match the handling of the TF1 to the rider’s ability to inspire confident handling and improve run performance.



When designing for competition we need a protagonist. Apollo Creed to our Rocky. In our CFD study the part of Apollo was played by virtual rider “Jane” on her Cervelo P5, while for the shakedown test, this was test rider Jan on his Stephens Super Trofeo.

To keep things fair we had built two Kú TF1 frames from the test riders fit coordinates and carefully checked those fit coordinates were transcribed to the brace of the Kú TF1 before heading to the Velodrome. There were a few variations, pad width and shape for example but we were ok with those, understanding what would need to be done.

Unbeknown to our test rider and the Alphamantis data analysts, there was a small variation between the two Kú TF11 bikes, it wasn’t just the fancy paint job! Would we be able to see that difference in the final CdA numbers? This was our sneaky confidence check of the data when time came to putting results in context.

The Alphamantis system requires the rider to complete blocks of around 10 laps, maintaining a consistent power input to the bike, and line around the track. That takes a degree of confidence only riding can develop. As test rider took the TF1 out onto the track, there was a huge buzz knowing that this was the first time anybody had ridden the Kú TF1.

It’s the nature of all shakedown testing that from the moment the wheels first turn the feedback notebook starts to fill up! Almost immediately everything from little tweaks to new component ideas start to take shape.

As the test rider worked through the test program, completing each test block, the data was beginning to roll in. It’s natural to gravitate to the track side data station, of course we tell ourselves it’s just a shakedown, try not to get too excited about performance numbers, but as the muffled conversations of the Alphamantis team looking at the raw data on screen turned to smiles and thumbs up the excitement was palpable.

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