4 Bar Linkage Calculator v3.0 - Rear 4-Link Anti-Squat & Roll Center Geometry

This document is a screenshot of a "4 Bar Linkage Calculator v3.0" spreadsheet (created 2004.12.04 by Dan Barcroft & Greg Blanchette) used to analyze rear suspension link geometry for a custom 4-link setup. Vehicle specifications entered include a 110.0 in wheelbase, 40.00 in tire diameter, 20.00 in tire rolling radius, 30.00 in vehicle CG height, 4,500 lb vehicle mass, 800 lb front unsprung mass, and 700 lb rear unsprung mass. Upper and lower link frame-end and axle-end coordinates (x, y, z) are tabulated, along with computed link vectors, lengths (37.457 in upper, 37.550 in lower), unit vectors, intercepts, roll points, link forces (6019.817 lb tension in the upper links, -7992.054 lb compression in the lower links), and slopes. The geometry summary reports 62.289% anti-squat, a 26.579 in roll center height, a -1.136 degree roll axis angle (roll understeer), and an instant center located 296 in on the X-axis and 53.371 in on the Z-axis. A plot shows top and side views of the linkage with the tires, upper/lower links, anti-squat line, 100% AS line, roll axis, roll center, and instant center graphically overlaid. Readers can learn the exact link mounting coordinates and resulting handling geometry for this rear suspension design.