Bicycle Fitting and Sizing

Serotta

Serotta has been a leader in bicycle fit for quite a while. The established the Serrotta Cycling Institute to further the goals of a better understanding of bike fit.

Fit Bikes

• Calfee Sizer Cycle
• Serotta Fit Bike
• San Giorgio Fig Jig

Kits

• Fit Kit
• Bikefitting.com
• Bike Fit Systems

Local Fitters

• NorCal Cycling in Santa Rosa. $75. They do a pretty good job. Much better than the average bike shop in the bay area. This is where I send most people that need a basic fitting.
• Whole Athelete, San Anselmo, CA, $220-295
• Craig Upton of Performance Lab HC , $150
• PK Racing, in Fairfax. $450-500. Primarily pro road/tri experts. They are very expensive and I have no personal experience with them other than the fact that they are only 3 blocks from my house.
• Cycle Sport, in Oakland. $125

or search Serotta by zip code

Links

• Jack's Bikes - A fit kit walk through
• Cyclemetrics link page
• Pruitt

Some Traditional Numbers

Crank Length

18.5% from top of femur to floor.

Inseam:

• < 29 inches - 165 mm crank
• 29 - 32 inches - 170 mm crank
• 32 - 34 inches - 172.5 mm crank
• > 34 inches - 175 mm crank

Frame Size:

• 54 cm or less, 170 mm
• 55 - 58 cm, 172.5 mm
• 59 cm or greater, 175 mm

Knee Angle

30-35 Degrees. More bend conserves more energy, less bend for more power.

Saddle Height

• Inseam (with cycling shoes) x 0.883 = Top of the saddle to the center of the bottom bracket. (beware oversized feet using this)
• Inseam (with cycling shoes) x 1.09 = Pedal spindle to top of saddle with pedal parallel to seat tube.

Trunk Angle

About 30-40 degrees from level. (45 at most)

Shoulder Angle

90-100 degrees.

Elbow Bend

15 degrees

Stem Length

• When in drops, axle obscured by bars.
• With arms bent 15 degrees in drops, plumb line from nose bisects stem at bars.

Handlebar Height

• 1-2 inches below the saddle for small riders
• up to 4 inches for taller riders.