Bicycle Geometry 101 (BG101) is an Excel-based bicycle fit and frame design program created by Martin Manning. It uses anatomical measurements of the rider to estimate the locations of the saddle and handlebars as well as the frame and component dimensions. The suitability of an existing frame design can be evaluated with respect to any desired position, or a new custom frame design can be created to match it exactly.

Wheel, toe, and drivetrain clearances, as well as brake mounting locations are calculated, and plots of the riding position, frame elevation view, drivetrain layout, and frame tube layout are produced. The design process, and the storage and retrieval of designs are automated through the use of visual basic macros, and a utility for generating miter templates is also included. Extensive documentation explains the use of the programs features. This program is being made available at no cost to promote the craft of bicycle frame building and the sport of bicycling in general.

N.B. Although Bicycle Geometry is created for use with Microsoft Excel, it does work with the free, cross-platform software suite (version 2.3 and newer) with some odd graphic issues in the "Position Plot" and tube mitre templates. The "solver" is untested under Linux users may find that the gnumeric open source spreadsheet works better with Bicycle Geometry. 

September 17, 2008

The current version of Bicycle Geometry 101 is BG101_v801.xls.

Documentation for BG101_v801 in PDF format is here.

Release notes for version 8.01 (July 2008):

Also of interest:

The Bicycle Geometry Project with a downloadable spreadsheet of many bicycles!

June 25, 2008

The previous version of Bicycle Geometry 101 is BG101_v800.xls.

Documentation for BG101_v800 in PDF format is here.

Release notes for version 8.00 (June 2008):                   

May 2, 2008

The previous version of Bicycle Geometry 101 is BG101_v720.xls.

Documentation for BG101_v720 in PDF format is here.

Changes in BG101_v720 include:

April 21, 2008

The previous version is BG_101_v710.xls.

Documentation for BG_101_v710 in PDF format is here.