Help tuning out understeer: Smaller front bar or Larger rear?
 

Hi all.

I am looking for help trying to tune out understeer on my weekend warrior/autox/eventual track day 97 Miata. Here is my current suspension setup:
Feal 441 Coilovers, 12k/8k
Racing Beat Tubular Front Sway Bar, 1.125-inch OD / 0.125-inch ID wall
Stock NA Rear sway bar

I do realize my big front bar is inducing understeer, however I am not sure which solution path is the 'better' one in terms of suspension theory. My options are:
Downsize Front Sway Bar (FM most likely)
Upsize Rear Sway Bar (FM, Racing Beat, or MSM OEM)

Was hoping to get some guidance here from people who know more about suspension setups than I do.

What part of the corner does the understeer happen? Have any in-car video?

What are your current alignment settings?

Alignment settings would be pertinent.
Also, what are your front and rear ride heights? Wheel and tire size?

The more info you can provide on your setup, the better feedback you'll be given.

Get a rear adjustable bar. I would play with roll couple settings using this spread sheet to find where you are now. You can also play with rear end ride height to dial it.
https://www.fatcatmotorsports.com/FC...ata_Online.htm

Try not to think of things in traditional ways of stiffer front=more understeer and stiffer rear=more oversteer. Instead think of grip as a bell curve. There is an optimum setting which equates to the peak of the curve. A change to either side of the peak produces less grip. Obviously, the key is finding the peak. And of course, you never want to take away grip but instead add grip to the side that has less grip.

An example is understeer being fixed with a bigger front bar because it solved an issue with excessive roll. Or adding front tire pressure (can sometimes be equated to adding spring rate) to solve understeer simply because too little air pressure was rolling over the tire.

But like others have said, the more information, the better. And of course, grip is in the tire. The fresher the rubber and the flatter the tire stays, the more grip you have, on either side of the car. And yes, a usual ubiquitous fix is raise the rear ride height.