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Endurance means to pursue a goal, no matter what might happen on the way. The DT Swiss ERC 1100 DICUT® is designed with this goal in mind. It unites top notch aerodynamics with comfort and reliability. Now bring on the cracks in the tarmac, rain and headwind situations.
The launch of the ERC 1100 DICUT® marks a new era for DT Swiss. With its introduction we launch a new and revolutionary road line up. One that picks up modern road riding and takes it to the next level.
Rim
The rim of the ERC 1100 DICUT has been developed in cooperation with our industry partners from Swiss Side one of the leading brands in aerodynamic optimization. Being one of the key components of the AERO+ concept, the rim of the ERC 1100 DICUT is a milestone in the history of DT Swiss wheel development. Find out more about the development process in the following chapters.
Spokes
Speaking about aerodynamics most of our competitors do not even mention spokes. We are putting spokes into the limelight. The ERC 1100 features a complete new spoke which has a bladed part for optimized aerodynamic characteristics and a round butted part for increased comfort.
Hub
Once again we raised the bar even higher. DT Swiss hubs are synonym for quality and high-end Swiss engineering hubs for more than 20 years. The new DICUT aero hub is proof of that, combining all our technology in a cutting-edge product, being aerodynamically optimized too.
Aero + describes our approach to optimize a wheelset via numerous engineering techniques all through its development process to guarantee the emerging product performs as good as humanly possible at a given moment in human and technological development. Aero+ is based on three pillars: DRAG, HANDLING & EFFICIENCY.
When setting ourselves the goal to realize the ambitious Aero+ concept, it was clear that we needed the best aerodynamics partner to get the drag chapter dialled. After all, DT Swiss is a behemoth in the world of wheel manufacturing, but world class aero knowledge needed to be brought in. Being close both geographically and regarding our mindset, with SWISS SIDE we have found the ideal partner. Go ahead and check out the fruits of this unique partnership.
Swiss Side is the No.1 brand in cycling aerodynamics. With over 50 years of Formula 1 experience, the SWISS SIDE team is revolutionizing cycling aerodynamics by bringing previously unseen development techniques to the cycling industry in order to maximize the performance of cycling products. SWISS SIDE brings the latest technologies and top-level engineering know-how for pushing the boundaries of aerodynamics, materials, construction and design, to bring cycling products into a new era.
Wind is all but unidirectional. A lot of factors have to be considered when trying to optimize a road wheel. Although the rider is responsible for the majority of drag, it's the wheel aerodynamics which can have the biggest influence on reducing the drag.
As a starting point, engineers build a CAD (Computer Aided Design) model of all components of the bike which are relevant to simulate a wheel's aerodynamic performance in a digital model. This model sets the arena within which all calculations of the wheels are made to optimize it to the max.
The CFD (Computational Fluid Dynamics) simulation
shows the airflow behavior of the CAD model and all
forces acting on the model in the relevant areas, which
are the tire and the rim leading parts of the wheel as
well as the hub area. To make sure that the airflow of
the simulation corresponds to the real world, data from
road riding under varying conditions has to be collected
and fed into the software. SWISS SIDE has been collecting
such data over many years with Swiss precision
to guarantee the most accurate simulation results
possible.
The geometry of the relevant areas directly influences
the alignment, the size and the turbulences of the
slipstream, which determines the drag and handling
characteristics of the wheel. These characteristics
have to be optimized for yaw angles occurring under
real riding conditions.
Now that the stage is set, SWISS SIDE's black box calculation software comes into
play. It consists of a sophisticated system of factors and algorithms and has been
developped in order to tune the characteristics of the rims in the desired directions,
better than any single engineer brain would ever be able to do.
We at DT Swiss enter the desired properties of the wheel into the software. The software
then continuously alters the wheel's geometry and goes through the whole
CFD calculation process with each alteration. Only to find the best matching geometry
to the desired properties. Eventually it spits out a selection of geometries who come
closest to the originally set desired properties.
Profile depth
30mm 60mmRim width
15mm 25mmTire width
23mm 30mmWeighting system
drag steering momentGeometry
Drag
low highSteering moment
low high
When everything is ready to head to the wind tunnel, engineers have sleepless nights. Will all the calculations have been right? After all, so far it has all only been in the world of 0 and 1's. The great advantage of wind tunnel testing is that it allows us to prove the calculation results with non rideable prototypes. It also provides repeatable, back to back comparable data to precisely document improvements made over the course of a product development process. Even the final production wheel goes through a wind tunnel test session to prove its aerodynamic performance before it is released to the market where it meets you, the rider.
The first prototype tests of the ERC 1100 DICUT® have taken place in autumn 2015. DT Swiss engineers and the product manager, as well as SWISS SIDE experts met at the tunnel to confirm the results of the CFD simulation and compare the prototype with benchmark competitor products. Find out about the results on the following pages.
DT SWISS
MAREK MEILI
Specialist Engineering Wheels
SWISS SIDE
JEAN-PAUL BALLARD
Technical Director & Co-Founder
SWISS SIDE
CHRISTIAN KLEINER
Aerodynamic Team Leader
DT SWISS
STEFAN RIEHLE
Product Manager Road
DT SWISS
MARTIN WALTHERT
Chief Technical Officer
DT SWISS
STEFAN SPAHR
Head of Engineering Wheels
The ERC 1100 DICUT® has super low drag numbers at all relevant yaw angles. Best of all it is right in the ballpark with the competition both when run with 25 mm and 28 mm tires.
All Wheels tested with Continental GP4000S
With an enormously impressive resume in getting anything aerdynamically perfect from Formula One cars right to the shopping cart (well not really, but you get the point), JP and his company SWISS SIDE were the ideal partner to cooperate with for our Aero+ concept. Hear from the man himself what he has to say about this Swiss melting pot of aerodynamics and manufacturing know how.
Wouldn't it be necessary to develop a wheelset with the bike?
It seems with the marginal gains that are possible it would be the only way
to really improve the system?
Our experience in developing wheels and bikes shows that a properly developed
wheel will perform the same regardless of what bike model it is then fitted to. Where
we can achieve the greatest gains is actually not just in the aerodynamic drag but
also in the aerodynamic stability and handling of the wheel. This is where significant
gains can be made for the entire system.
Why are the spokes not simulated in CFD?
The spokes are not necessary for developing the rim shapes. Leaving them out
simplifies the CFD model and allows us to simulate more time & cost efficiently.
How does the black box software work?
Our black box software analyses the influence of all the important design parameters
of the rim, Eg. rim, height, width, wide point, curvature. It can then combine
the simulate matrix of the many hundreds of permutations to determine which combination
of parameters gives the best performing rim shape. The other components
of the wheel (hub, spokes) are fixed so they are not changed in the simulation by the
black box.
My average riding speed is barely above 25 km/h
– do I really profit from aerodynamic optimization?
Aerodynamic drag is the biggest resistance a rider has to overcome above
a speed of 15 km/h. So above this speed, aerodynamics is priority no.1.
Why is only the front wheel tested?
The front wheel is where the majority of performance is to be found. We develop
wheels on a partial bike model. In particular, the front wheel profile is developed in
the presence of the bike. This profile then works with the greatest aerodynamic
efficiency also for the rear wheel which is in the dirty air at the rear end of the bike.
How is drag actually measured in watts in the wind tunnel?
Under each wheel in the wind tunnel is a balance which measures all the forces at
work, either on the wheel alone, or on the complete bike (and rider) system depending
on what configuration is being tested. Knowing the drag force, the drag power in
watts is then calculated by multiplying by the speed at which the wheel is tested.
When you look closely at the drag values of the ERC 1100 DICUT® you see it isn't
better than its competition, in fact it is slightly behind in some spots. So why does
DT Swiss make such a buzz then about this?
This wheel was developed with a Formula 1 approach. The only thing that matters
is what delivers the fastest complete system. The differences between the top
level competitor wheels are within 1 watt. So this is not where the big improvements
can be made. So we set a strong focus on handling and aerodynamic
stability for the development of the ERC 1100 DICUT®. Why? Because there is on more fact.
The complete bike only makes up for 25% of the overall drag, the wheels even less at 8%, while the rider causes 75% of it. So why is the wheel still important in this calculation? Follow us to find out.
In order to stay aero in the first place, you have to stay comfy no matter the riding situation, because only then will you be able to keep an aero position, which affects those big 75%. And this is WHY the handling characteristics of a wheel are key.
Here's the graph that really matters: The ERC 1100 DICUT® is the best handling wheel in wind situations commonly found on the road. This is true independent of the tire width you chose to ride. Only these properties allow you, the rider, to stay aero and that's directly influencing those big 75% of drag YOU create. This is why DT Swiss makes such a buzz about the ERC 1100 DICUT®.
All Wheels tested with Continental GP 400S
Comfort, grip and rolling resistance define efficiency. Wheels have a direct and important effect on how the tires perform regarding comfort, grip and rolling resistance. During the development of the ERC 1100 DICUT® we have paid close attention to these factors as they play an integral role in the Aero+ concept, because you can only stay aero, when you stay in control.
A wider contact area and lower pressure of the tire result in more grip and more comfort. The following illustrations clearly highlight the influence of a wide and optimized rim-tire combination.
X1 < X2
The wider tire has a wider contact area in the
direction of the cornering force occuring when
cornering. Therefore it offers better grip.
F1 < F2
The air in the tire with less pressure requires
less force to compress upon an impact from the
road, therefore it offers more comfort.
H1 > H2
Wider tires build higher, therefore they have better pinch flat protection
at the same pressure, or can be run at lower pressures respectively.
BETTER SUPPORT
The wider rim supports the tire better. Therefore it allows for more
aggressive cornering before the tire starts to fold or to run lower pressures
respectively.
Do wider tires on wider rims really have a better rolling resistance? And what about aerodynamics? If you have better rolling resistance but poorer aerodynamics, how can the rider really benefit and which set-up is the best one? The wide tire with better rolling resistance or the narrow one with better aerodynamic characteristics? Questions after questions. To answer them precisely, we did comprehensive tests. Find out what answers emerged.
A narrow tire leads to a long contact patch
which leads to higher rolling resistance.
Explanation: when rolling a bigger part of
the tire has to deform, requiring more energy.
A wide tire leads to a wide contact patch
which leads to lower rolling resistance.
Explanation: when rolling a smaller part of
the tire has to deform, requiring less energy.
1.
At the same pressure 28 mm tires have lower rolling resistance
than 25 mm tires. The same tire rolls better the higher the pressure
(measured on a 18 mm inner width rim with Continental GP4000S).
2.
Wider rims have a positive influence on rolling resistance
(measured on DT Swiss rims with Continental GP4000S 28 mm @ 7 bar).
Rolling resistance should always be connected to the aerodynamic performance. Therefore we compared rolling resistance and aerodynamic drag to find out about the overall resistance / performance.
VERDICT: Riding below 35 km/h the «comfort» set up with a 28 mm tire creates less overall resistance compared to the «aero» set up with a 25 mm tire. Riding above 35 km/h the «aero» set up is clearly the better solution, especially at higher speeds around 45 km/h. The conclusion is that riding at lower speeds the influence of drag is relatively small compared to the influence of rolling resistance. Vice versa the influence of rolling resistance descreases compared to the influence of drag when riding at higher speeds.
#Longdaysout
