Ford Focus Forum, Ford Focus ST Forum, Ford Focus RS Forum - View Single Post - Passive rear steer revisited
View Single Post
Old 06-12-2007, 04:44 PM   #23
Focus Fanatic
thenorm's Avatar
Join Date: Oct 2004
Fan#: 14947
Location: Vancouver, BC, Canada
What I Drive: '04 liquid grey ZX3, built for FSP

Posts: 2,174
Points 6,173, Level 51
Points: 6,173, Level: 51 Points: 6,173, Level: 51 Points: 6,173, Level: 51
Level Up 12% Completed
Level up: 12% Level up: 12% Level up: 12%
Forum Activity 7%
Activity: 7% Activity: 7% Activity: 7%
FF Reputation: 40 thenorm Great Standing Member
Buy-Sell-Trade Rating: (5)
Originally Posted by S1lkwrm View Post

- turn left and the suspension rolls right and rear right tire toes out and I think rear left toes in causing the rear steer.
umm, isnt this backwards? when u compress the suspension, the tires toe in. This has the effect of lessening the yaw (rotation) induced by sudden steering imput.
The suspension is designed so that Joe Shmoe, when he panic turns around a dog that runs into the road, doesnt loop it into a telephone pole. It was not designed to improve turn in for racing. It is an economy commuter car afterall.

If you look at the control arms of the rear suspension, you'll see that the control arm towards the front is short than the rear, when the suspension compresses it has a shorter arc and it esentially pulls its part of the "blade" trailing arm towards the middle of the car. this flex of the control blade is what toes the tire in on suspension compression.

That why after I lowered my car, my rear toe visibly pointing in.

to modify the PRS, you would need to change the starting position of the front control arm. If it started out aimed downwards instead of horizontal, the inital swing of the arc would push the control blade out (causing toe out), then as it passed horizontal would pull the blade back in (toe in).
if that makes sense to anyone else

umm ya, jsut noticed this was a dead thread that i was responding too, but too late now. this info is still important
May 2014 ROTM, June 2015 ROTM
for auto-x: '04 Liquid Grey ZX3
for street: '02 Infrared SVT
thenorm is offline  
    Reply With Quote