(meant in a nice way) but from what i can gather the big question would be bump steer unless tour inner
s/rack joints were in line with the upper and lower inner w/bone mounts. I'm sure there will be more said shortly
I have a question for the suspension designers out there!
If I had a chassis that had the top wishbone mounts about 2-3 centimeters nearer to the centerline of the car than they should be. Suppose that
instead of moving them outwards to where they should be, I was to make longer wishbones. Would this effect the handling of the car dramatically?
Would it result in serious understeer in cornering?
The roll anges would interfere with the brake centres thus increasing the thread length by about 120%.
To be serious, I dont have a clue, and would be very disinclined to change anything like that without some serious professional input.
I'm not really a suspension freak(meant in a nice way) but from what i can gather the big question would be bump steer unless tour inner
s/rack joints were in line with the upper and lower inner w/bone mounts.
I'm sure there will be more said shortly
It would change a few things to varying degrees --- camber change on roll and bump, have more minor effects on bump steer and roll centre position
when cornering.
Reduction of camber change on bump and under braking is good but the one that is likely to be a major problem is camber when cornering -- the book
design dosen't put enough load on the inside edges of the tyres as it is so needs quite a bit of static negative camber. If you are using Sierra
front end parts you could win some of it back by using offset mushrooms to increases the virtual king pin inclination.
KPI, virtual or otherwise, is engineered in as a direct ratio to the softness of the front suspension, if you have hard suspension, the less KPI you
need.
You could only win back the camber change, if the suspension was sufficiently soft to change the angle of the chassis to the upright with the steering
angle applied (no steering angle change, no camber change with KPI)
quote:
Originally posted by nludkin
I have a question for the suspension designers out there!
If I had a chassis that had the top wishbone mounts about 2-3 centimeters nearer to the centerline of the car than they should be. Suppose that instead of moving them outwards to where they should be, I was to make longer wishbones. Would this effect the handling of the car dramatically?
Would it result in serious understeer in cornering?
Well, if the top wishbones were longer then the axis of rotation would be in a different place and the arc travelled by the wishbone would be
different?
Surely this would change the graduation of camber from "designed" spec. Would it be significant though?
You could try to quantify the change by entering both the existing and the proposed geometry into the demo version of SusProg 3D (bevinyoung.com.au)
or the suspension spreadsheet found in the files section of http://groups.yahoo.com/group/Locost_North_America/ . Just remember: "garbage in,
garbage out."
This, taken with some of the previous posts (and reading some Carroll Smith and Alan Staniforth) will at least educate your guess.
Regards,
Pete
"Suspensions are peculiar things," he said, as if trying to explain away some awkward relatives.
quote:
Originally posted by nludkin
Well, if the top wishbones were longer then the axis of rotation would be in a different place and the arc travelled by the wishbone would be different?
Surely this would change the graduation of camber from "designed" spec. Would it be significant though?
Don't do it.
The angle at the chassis end and the shorter top bone give the "correct" camber change in roll, changing this will dramatically affect the
dynamics of the car
quote:
Originally posted by NS Dev
Don't do it.
The angle at the chassis end and the shorter top bone give the "correct" camber change in roll, changing this will dramatically affect the dynamics of the car