toe migration

[faeez]

i am just wondering, i have a toe migration of 1mm over 25mm bump, how do i reduce that? coz ive read somewhere that a number more than 0.5 is going to make the car unstable.

[faeez]

i am just wondering, i have a toe migration of 1mm over 25mm bump, how do i reduce that? coz ive read somewhere that a number more than 0.5 is going to make the car unstable.

[exFSAE]

You've read that somewhere? According to who? Why? On what type of vehicle?

Are you going to see 25mm of bump travel in the suspension?

What angle change is that? Given tire data, how much force change does that yield?

[Drew Price]

This is called bump steer. The term migration is only used to describe the three-dimensional movement of the instant centers.


This is a very simple concept, and arranging the steering links to minimize or eliminate bump steer is well covered in every suspension book I have ever read.


Go read some of them!



Or better yet, play with the location of the link in your model and see what the change is! It will quickly be obvious what the effect of moving the pivots does.



I will give you a hint: make the instant centers of the suspension links and the steering link the same point (make them intersect), and keep them at the same point through their travel!



Best,
Drew