September 27, 2014

FLO Cycling - Getting Started with your FLO Wheels



Getting Started with your FLO Wheels

To help you get started with your new FLO wheels we have put together an Education Video Series that features 12 videos.  We hope you find these videos helpful.  If you have any questions about your new wheels or the videos below, please let us know.  Enjoy every mile on your new FLO wheels.

Take care,

Jon and Chris


How to Install a Rim Strip


How to Install a Silca Valve Extender


How to Install a Clincher Tire


How to Remove a Cassette


How to Install a Cassette

How to Install a Front Wheel


Horizontal vs. Vertical Dropouts


How to Install a Rear Wheel in Vertical Dropouts


How to Install a Rear Wheel in Horizontal Dropouts


How to Install a Freehub


Hub Maintenance


How to True a FLO Wheel

September 24, 2014

FLO Cycling - Aero Wheel Tutorial


We are republishing some of our best blog content.  After nearly 3 years of writing and roughly 150 articles, surely some of our newer fans have missed some of our best stuff.  This week we are going way back to our Aero Wheel Tutorial.  If you've ever wondered why an aero wheel is faster, read on!


Aero Wheel Tutorial
Let’s start by defining some terms…
Yaw Angle
A yaw angle is the angle at which the wind interacts with the wheel.  Take a look at the pictures below.  In Figure A, the wind (blue arrow) is hitting the wheel at 0 degrees.  This is known as 0 degrees of yaw, and what you experience when the wind is blowing straight at you.  In Figure B, the wind is now interacting with the wheel at a 20 degree angle.  This is known as 20 degrees of yaw and the cyclist would a feel a combination of head wind and side wind.   



Figure A
Figure B

Leading Edge
Let’s start with a visual.  Imagine a canoe moving through a calm lake.  The front of the canoe is the first part of the boat to cut through the water.   It is therefore defined as the “leading edge”.  A wheel in the wind is no different.  Remember, air is a fluid just like water.
A wheel can have two leading edges.  The tire at the front of the wheel, and the carbon fiber fairing at the back of the wheel.  When a wheel is at 0 degrees of yaw, the front of the wheel is the only leading edge.  This is because the back of the wheel is “hiding” behind the front of the wheel (see Figure C).  When a yaw angle of greater than 0 degrees is introduced, we now have two leading edges.  Figure D shows the wind at 20 degrees of yaw.  The back of the wheel can no longer “hide” behind the front of the wheel and sees it’s own air.  It is therefore defined as a leading edge. 

Figure C

Figure D

Drag
Drag is defined as the force on an object that resists its motion through a fluid.  Let’s use another water example.  If you stand in waist deep water and try to run forward, the force you feel holding you back is drag.  Air also has drag, just not as much as water.      
Lift
Lift or “side force” is one of the most important forces to consider when designing aerodynamic cycling wheels.  To help you better understand the three main components of lift, let’s shift our focus to the skies and talk about airplanes.
Figure E

The wings of an airplane allow it to fly, but how?  To answer this, let’s look at the forces acting on an airplane (Figure E).  Thrust is the force generated by the engine of the airplane to move it forward.  Drag is the force exerted by the air that resists the forward motion of the airplane.  Let’s ignore these two forces for now. 

Gravity is the earth’s attractive force that wants to keep the airplane on the ground.  Lift is the force we need to create in order to get the plane off the ground.  To take flight, we need the lift force to be greater than the gravitational force.  Lift is generated by the wing.   A wing has three major components that contribute to the lift force it produces.  Those three components are:

1. The shape of the wing. 
2. The wing’s angle of attack.
3. The velocity or speed of the wing.

The shape controls the way the air (fluid) moves around the wing.  By controlling the airflow, we can create areas of high pressure below the wing, and areas of low pressure above the wing.  Anytime there is a difference in pressure on opposite sides of an object, the high pressure side pushes the object towards the low pressure side.  Think of a balloon.  The more air (pressure) you blow inside of the balloon, the bigger the balloon gets.  This is because the high pressure is pushing the inside of the balloon out.  In order to take flight we have to create a high enough pressure under the wing to lift the plane off of the ground.  
The angle of attack is the angle that the wing moves through the air.  This is the same as the yaw angle of a wheel.  As you increase the angle of attack, you increase the lift force until you reach the critical angle of attack.  The critical angle of attack is the angle that produces the maximum lift.  Think of sticking your hand out of the window of a moving car.  By turning your hand up or down (changing the angle of attack), you can make your hand rise or fall.  If you turn your hand too far in either direction, it no longer moves up or down but instead straight back.  
Finally we have the velocity or speed at which the wing travels through the air.  The simple answer here is, the faster you go, the more lift you create.  
Wheel Design
When designing effective aerodynamic race wheels there are in our opinion to very important points to consider.  The first point is the reduction of drag.  In order to be fast, the wheel must reduce aerodynamic drag as much as possible.  The second point is the ride quality and stability of the wheel.  Anyone who has ridden deep wheels in a strong side wind knows they can be a challenge to control.  Therefore, it is important to design a wheel that has good crosswind stability. 
Side Force (Lift) and Drag
In the world of cycling, Lift is called Side Force.  Figure F shows a wheel at 0 degrees of yaw.  In this case the wheel only experiences drag. Since the wind flows evenly around both sides of the wheel, side force is equal to 0.  
Figure F

Figure G shows a wheel at 20 degrees of yaw.  Thinking back to our airplane example, we have increased the angle of attack.  This produces a higher side force on the side of the wheel facing the wind and produces lift.

Figure G

Let’s now consider the side forces that a standard training wheel experiences.  Because a standard training wheel has very little rim depth, it generates very small side force.  For sake of argument, the drag is more or less equal to the side force.
An aero wheel however, has a much deeper rim profile and an increased surface area.  The increased surface area generates a higher drag force.  An efficient fairing shape will increase the side force.  The key is to design a fairing shape that produces a higher percentage of side force relative to drag.  
Why do we want side force?  Let’s start with vector forces.  When a force pushes on a surface at an angle, a portion of that force pushes the object in the X direction and a portion of that force pushes the object in the Y direction.  Take a look at Figure H
Figure H

Let’s look at the vector components of side force and drag acting on a wheel.  Figure I shows that the Y component of side force actually opposes the Y component of drag.  In theory, if we can generate a side force high enough relative to drag, the Y component of side force will be greater than the Y component of Drag.  When this happens, the wheel will actually be pushing you forward.  This is known as negative drag.

Figure I
Here are two numeric examples.
Standard Box Rim Wheel
Total Drag Force = 100g
Drag Force Y Component = 93.97g
Total Side Force = 100g
Side Force Y-Component = 34.20g
Resultant Drag Force = (Drag Force Y-Component) - (Side Force Y-Component)
Resultant Drag Force = 93.97g - 34.20g
Resultant Drag Force = 59.77g
Aerodynamic Wheel
Total Drag Force = 150g
Drag Force Y Component = 140.95g
Total Side Force = 450g
Side Force Y-Component = 153.90g
Resultant Drag Force = (Drag Force Y-Component) - (Side Force Y-Component)
Resultant Drag Force = 140.95g - 153.95g
Resultant Drag Force = -12.95g
Cross Wind Stability or Yaw Torque
Imagine a seesaw on the playground.  Let’s put a child weighing 50 lbs on one side and a child weighing 70 lbs on the other side.  We all know that the 50 lbs child will quickly rise up in the air.  
In theory the front wheel of a bicycle is the same.  We have the front half of the wheel, the back half of the wheel, and the steering axis.  If we push on the front half of the wheel and leave the back half alone, the wheel will turn around the steering axis in the direction of your push.  Take a look at Figure J.  
Figure J

If we are going to make a wheel that is stable in cross winds, we want the side force on the front half of the wheel to be equal to the side force on the back half of the wheel.  This would be the same as placing a 50 lbs child on both sides of the seesaw.  This will prevent any turning of the wheel.  If the side force on the front of the wheel is greater than the side force on the back of the wheel, any gust of wind will cause the wheel to quickly turn in one direction. 

We hope this tutorial has helped you understand the basics of cycling wheel aerodynamics.  For more great content, please register for our free monthly newsletter at the top of the column on the right.  We send links to all the articles we post during the month.  If you have any questions please feel free to ask!
All the best,
Chris

September 12, 2014

FLO Cycling - Interbike 2014, Pictures Gallery


Here is our annual Interbike Gallery.  I hope you enjoy.

Outdoor Demo

A row of Scott mountain bikes ready for testing

Smith Optics Line



Our buddy Mal from Smith with the new Koroyd and Pivlock V2's

Argon 18 E-118's for testing

Felt's new Outfitter bike.  Bosch motor assist that goes anywhere.  Fishing, hunting you name it.  Jim has used it to haul out an Elk when bow hunting.




Interbike Show

Josh Poertner from SILCA released the new SuperPista Ultimate Floor Pump.  This thing is a work of art and an engineering marvel.






Smith Koroyd Helmet

Smith Koroyd Helmet

Smith Optics Pivlock V2

Stan's Threaded Valve Extenders for tubeless setups on deep wheels

Scott Plasma 5 Premium

Scott Addict Team Issue Di2 
Sebastian Kienle's Scott Plasma 5, Rad.

BMC teammachine SLR03, $2,200

Rinny's Felt IA FRD

Felt DA Line

Felt DA1

Felt IA 2

Felt IA 3

Felt IA 4

Felt Z5

Wahoo Fitness Kickr

Argon 18 E-118 
Quintana Roo PRsix Ultegra Di2 Race

Quintana Roo PRsix Dura Ace Race

Giant Propel Advanced SL 0

Litespeed C1R Race

Litespeed L1R Race

Scott's RedBull Bike

Nite Rider's new 3ft clearance marker.  It's an FDA approved laser.

Profile Design FC25 Hydration System

Profile Design FC25 Hydration System


Blueseventy Helix

Michellie Jones' Felt IA

That's a cool bag

XLAB Torpedo

The new Falco V in all Black

Speed Play's new Zero Aero Pedal (Very Cool)

Speed Play's new Zero Aero Pedal

Boardman AiR/TTE 9.8

Fuel Belt's new Helium Line.  Lots of Colors.

Our fellow Canadian Friend Jenny Fletcher

K-Edge's awesome Chain Catcher and Magnet Mount
I hope you enjoyed the pics.  Ok, it's time to get back to work.  You may have to wipe your chin =].

Take care,

Jon