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set up help

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Looking for advice from people smarter than me on sway bar variances based off of my set up listed below. It looks like the 18mm bar is the go to bar in the rear but how do you account for tire side wall sizes when comparing sway bars?

2005 Mustang GT 3V 70% autocross 30% HPDE
Current set up:
560 F 280 R spring rates (I initially had 392 rears and swapped to 280's to test)
Whiteline front sway bar, relocation brackets, lower control arms, watts link
Stock 2005 GT rear sway (20mm i believe)
18x10 wheels with 295/40-18

What would be the benefit/handling characteristic of dropping to a 18mm rear bar taking into consideration my spring rates and tire size?

I figure this is a clear as mud question but im trying to research as much as possible before the start of the 2020 season.
 

ArizonaBOSS

Because racecar.
Moderator
8,730
2,734
Arizona, USA
A smaller rear bar will be more compliant, allowing more rear body roll and generating more grip at the rear of the car. If your car is neutral now, this will add understeer.
 

Grant 302

basic and well known psychic
Did you notice the change from 392 to 280 lb./in. springs?

The shift in handling balance should be less than that rear spring change. Both changes are toward understeer and should net more rear grip.
 

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