Road Revolution 18

#Longdaysout

Endurance
Riding

Long Days Out

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.

ERC 1100 DICUT

ERC 1100
Dicut®

Marking a new era

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.

1 2 3 The Wheel
  • 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.

THE
Concept

A revolutionary approach

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.

TEAMING UP

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.

DT SWISS
SwissSide

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.

Beating Drag

Beating
Drag

A revolutionary approach

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.

The Base

A revolutionary approach

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.

1 2 3 4 5 6 7 8 All relevant Parts

RELEVANT PARTS OF THE BIKE ARE:

  1. The headtube

  2. Frontal area of the downtube

  3. The fork

RELEVANT PARTS OF THE WHEEL ARE:

  1. The brake rotor

  2. The hubshell

  3. The tire

  4. The rim

  5. The spokes

CFD Optimization

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.

1 2 3 The Slipstream

Slipstream

  1. Tire leading area

  2. Hub area

  3. Rim leading area

Number Punching Power

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.

INPUT
BLACK BOX PROCESS

Profile depth

30mm 60mm

Rim width

15mm 25mm

Tire width

23mm 30mm

Weighting system

drag steering moment

OUTPUT
BLACK BOX PROCESS

Geometry

Schema Tire

Drag

low high

Steering moment

low high
Wind Tunnel

Getting Real
in the Wind Tunnel

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.

1 2 3 4 5 6 Inside The Tunnel

Inside The tunnel

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 Graph Facts

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.

ERC 1100 DICUT® 47, 28c

ERC 1100 DICUT® 47, 25c

Reynold Aero 46, 25c

ZIPP 303 FC, 25c

All Wheels tested with Continental GP4000S

Drag Power

JP From Swiss Side

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.

From Swiss Side

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.

HERE IS THE
ONE 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.

Ride Bike and Wheel
The Big unnamed

Handling
The big unnamed

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.

The Graph Facts

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®.

ERC 1100 DICUT® 47, 28c

ERC 1100 DICUT® 47, 25c

Reynold Aero 46, 25c

ZIPP 303 FC, 25c

All Wheels tested with Continental GP 400S

Steer Moments
Efficiency

Achieving
Efficiency

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.

Comfort & Grip Matter

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.

Centrifugal Force

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.

More Comfort

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.

Wide and Optimized

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.

Low Pressure

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.

More Comfort

Rolling Resistance

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.

Resistance

Contact surface narrow tire

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.

Narrow Tire

Contact surface wide tire

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).

Tabelle 1

2.
Wider rims have a positive influence on rolling resistance (measured on DT Swiss rims with Continental GP4000S 28 mm @ 7 bar).

Tabelle 2

ROLLING RESISTANCE

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.

Rolling Resistance

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.

ERC 1100 DICUT®

Front Tire
Rear Tire
Technical Specifications

#Longdaysout