Analysis of Ackermann Steering Geometry

Wm. C. Mitchell; Allan Staniforth; Ian Scott

doi:10.4271/2006-01-3638

2006-12-05

Analysis of Ackermann Steering Geometry 2006-01-3638

Ackermann steering geometry relates the steer angle of an inside tire to that of the outside tire. When turning the inside tire travels a shorter radius than the outside tire and thus must have a greater steer angle to avoid tire scrub. Classic Ackermann minimizes scrub by positioning both tires perpendicular to the turn center. It can have a significant impact on tire wear [1]. Ackermann analysis can also be used as a tuning tool in cases where classic Ackermann may not be the objective.

Ackermann has been around longer than the motor vehicle - over a century - but there is little rigorous analysis in the literature. There are two common measurements of Ackermann which give very different results. Both are used in texts and computer programs[8] Yet a literature search revealed only a couple sentences discussing the relationship between the two.

This paper presents a mathematical analysis of Ackermann which explains the two measurements and develops a formula relating the two metrics. It also derives additional analytical tools which provide better understanding of Ackermann steering geometry.

SAE MOBILUS

Subscribers can view annotate, and download all of SAE's content. Learn More »

Access SAE MOBILUS »

Digital $37.00 Print $37.00

Preview Document

We also recommend:

Standards

SAE Mobilus®

Publications

News

Events

Professional Development

A World in Motion (PreK-12)

Participate with SAE

SAE Membership

Donate

Analysis of Ackermann Steering Geometry 2006-01-3638

SAE MOBILUS