FLLD McPherson vs Double A Arm

Hi All,

I am working on a mid-engined trackable street car F40%/R60% weight bias and the front suspension is double A arm, rear is McPherson.

I am redesigning the rear cradle for a powertrain change and will also eliminate the McPherson setup and replace it with a double A Arm design.

I've modeled the current "known good" setup and used the critical values of ride height, track widtg, roll center ht., instant center widths & anti-dive as targets while designing my double A-Arm system

As this is my first time doing such a conversion..I am learning a bit...and the major anomaly that I need help understanding is the effect on FLLD.

The stock McPherson rear modeled a FLLD @ 30.5%...and just as the program describes...the car does currently have a neutral-understeer tendency which is cureable with throttle input.

My Double A Arm design however produced the more "standard" FLLD @ 45%...and described expected performance to have a neutral-oversteer tendency...which I am fine with.

However...I have to ask...is it typical for FLLD to change so much from the change in kinematics alone...or is it likely I have made a mistake in my modelling?

Many thanks, Josh

Please excuse my "senior moment", but "FLLD"?

If it's referring to the roll resistance balance, then it is certainly possible, even inevitable, that it will change.

Hi Gord,

Yessir, Front Lateral Load Distribution vs Rear.

Thank you for the reply, I appreciate it.