Wheel Aerodynamics


Disclaimer
Basis Systeme netzwerk (BSn) makes no representation or warranty, express or implied with respect to this publication or the programs or information described in this publication. In no event shall Edward C. Zimmermann, BSn, it employees or contractors be liable for specific, indirect, or consequential damages.

Trademarks other than those owned by BSn used throughout this article belong to the owners and are used here in a purely editorial fashion.

The total power required to ride a bike is:

  1. Power lost to aerodynamic drag: (½rhoCdAVA3)
  2. Power loss from rolling resistance of tires: (CRRWTVG)
  3. Power to rotate wheels (FwVG3)
  4. Power to overcome gravity on a hill (WTVGsin(arctan(RoadGrade)) (varies greatly)
  5. Friction losses in the drive and bearings (small except for chain line cross over)
  6. Power to accelerate and power losses from deceleration (converted to heat).
Power required = ½rhoCdAVA3 + CRRWTVG + FwVG3 + WTVGSin(Arctan(RoadGrade)

Aerodynamic drag represents the largest resistance while riding over level ground.

UCI Wind Tunnel Data
Wheel Name Weight (g) Rotating Drag(g)
24" Wheel
Trialist Flat Carbon Disk 950 97
Accel Kevlar Lens Disk 480 100
Vortex 12 Spoke Prototype 790 109
Hooker 18 Aero Spoke, Aero Rim 490 136
Elite 18 Aero Spoke, Aero Rim 500 154
650c Wheel
26" Accel Kevlar Lens Disk 590 95
Trialist Flat Carbon Disk 900 101
26" HED CX 18 Aero Spoke 850 139
Elite 18 Aero Spoke, Aero Rim 530 145
700c Composite Spoke Wheel
Aerosports 3-spoke Prototype 720 106
Trispoke (3-spoke) 720 112
Specialized (3-spoke) 1330 114
Zipp (3-spoke) 850 129
Corima (4-spoke) 1590 131
FIR Halley (3-spoke) 1530 142
700c Disk Wheel
Gipiemme Lens Disk 1107 101
Trialist Flat Carbon Disk 1035 105
Carbotec Lens Disk 1135 108
Spengle Lens Clincher Disk 1480 109
Zipp 950 Carbon Flat Disk 950 112
HED Flat Carbon Disk 1050 114
Accel Kevlar Lens Disk 710 118
Radsport Lens Disk 1900 123
700c Steel Spoke Wheel
Roval 18 Aero Spoke, Aero Rim 680 149
Elite 18 Aero Spoke, Aero Rim 580 162


University of Bath, UK (Cycling Plus):

The following were measured over a range of crosswind angles:

axial force coefficient Cx = Fx / (0.5 rho V2 S)
side force coefficient Cy = Fy / (0.5 rho V2 S)
yawing moment coefficient Cn = Mz / (0.5 rho V2 S D)
rho = air density
V = air speed
S = reference area
D = diameter
axial force coefficient Cx
Wind Angle:0.07.515.0 22.530.037.545.055.065.0
Conventional 36-spoke 0.047 0.057 0.061 0.059 0.058 0.070 0.057 0.045 0.029
Campagnolo Shamal 0.037 0.047 0.043 0.045 0.036 0.028 0.018 0.010 0.000
HED CX 24-spoke 0.035 0.028 0.034 0.041 0.042 0.039 0.030 0.019 0.011
Specialized TriSpoke 0.036 0.038 0.028 0.031 0.028 0.020 0.009 0.006 -.001
FIR TriSpoke 0.036 0.026 0.034 0.041 0.037 0.032 0.020 0.011 0.002
HED disk (lenticular) 0.036 0.020 -.004 -.005 0.000 0.001 -.003 -.005
ZIPP 950 disk (flat) 0.036 0.023 0.013 0.017 0.018 0.017 0.016 0.016


Vendor Data

Brand 0° Yaw 5° Yaw 15° Yaw 30° Yaw Side Force (45°) Wheel Speed = 29 MPH
Air Speed = 29 MPH

Drag at 0°, 5°, 15°, 30° yaw measured
in the plane of the wheel in grams
(Error ± 5 grams)

Side Force drag measured in
the plane of the wind in grams
(Error ± 10 grams)

Note: The lower the Side Force, the less effect a cross wind has on bicycle handling.

 

 

 

 

 

 

 

Source XNG!

XNG! 55 61 74 80 344  
Campagnolo Shamal 52 61 78 88 346  
Campagnolo Vento 53 63 80 93 355  
Mavic Pro 53 64 79 92 349  
Campagnolo Bora 55 68 81 94 346  
Corima 55 68 81 94 346  
Mavic Expert 56 69 84 103 358  
Gipiemme 57 70 80 88 347  
Ambrosio 57 70 80 87 348  
Torelli Wide Guy 57 65 85 96 350  
F.I.R. 57 70 80 87 346  
Zipp 340 65 67 77 81 338  
Am Class Vrim low profile 65 67 77 81 338  
HED CX 67 69 78 85 369  
HED Jet 68 70 78 85 372
Zipp 440 68 70 80 88 370  
Am Class Vrim Tubular 68 70 80 88 370  
Zipp 530 68 72 81 89 378  
Am Class Vrim Clincher 68 72 81 89 378  
Giant Carbon Road 68 71 77 97 431  
Cosmic Carbon 68 71 78 86 370  
Zipp 950 flat disk 75 70 60 211 1422  
HED Flat disk 77 71 57 200 1387  
Mavic Comete flat disk 77 73 57 204 1394  
Specialized Ultralight 78 72 70 68 460  
Nimble 79 74 70 64 383  
Aerospoke 79 92 99 109 411  
Spinergy Rev-X 84 73 71 70 457  
Corima 4 spoke 94 88 80 74 526  
Trek/Rolf 98 107 110 114 383  
Spengle 3 spoke 108 101 94 89 399  
Wheelsmith Accelerator 111 121 134 141 331  
Cane Creek Crono 112 121 135 142 330  
Mavic Helium 233 238 244 249 317  



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