Setup for neutral street handling?

[snakebit]

I'm looking for the simplest route to achieving neutral to slight understeer for my 99. I removed the stock rear bar but it still feels like there's a bit of oversteer.

I've heard that roadracers prefer the RB hollow front bar and no rear bar. Seems to me that might understeer rather heavily, as the RB bar is over twice as stiff as stock.

What bars have you tried and with what results? I plan to retain the springs and Bilsteins that came with the 10AE. I have no objection to the current amount of body roll nor do I wish to stiffen the ride much more if I don't have to. I'm also hoping to avoid all the recommended reinforcements that go with stiffer front bars in the 99-00 Miatas with their wimpy front bar mounts.

I'm wondering if just going to stiffer bar bushings in front would do the trick, maybe add RB end links too. That worked for my 1st gen RX7.

Thanks for your input.

[99mx5]

I have a '99 Sport (same Hard-S suspension as your 10AE). I have tried stock sport sways, RB sways and a mix. The set of RB sways made the car tail-happy, the RB front and no rear swaybar made the inside front wheel lift in the turns. I have found that the most neutral combination was the RB hollow front swaybar and the sport rear swaybar. I now have Tein FLEX coilovers but I have kept this swaybar combination and it seems to work well. I also installed the front swaybar bracket support blocks.

Street handling is very neutral with the Bilsteins and very slight understeer with Tein FLEX 9/6 spring rates.

If you want to fine-tune your handling, adjusting the front and rear tire pressures will change the car's turning habits.

[snakebit]

Thanks for the info. It sounds like I ought to be able to achieve neutral handling by running a smaller front bar than the RB and no rear. FM solid bar maybe? Not sure if that would lift the inside wheel like you experienced, but I'm only running street tires.

I do have the front tires a couple pounds lower than the rears but that doesn't do enough.

[Tom @ Fast Forward]

I had the problem of severe lean coming out of the turns. I installed the RB large front anti-sway bar and the smaller rear RB anti-sway bar. My first time out wih them, I had oversteer and worried about it. Then I installed new tires (Toyo 225-50/15 RA-1) and that problem seemed to disappear. When I saw that it still had severe nose dive, albeit straight now, I switched out the Bilsteins for the JIC 12/10 coil overs. They cured the nose dive and aided the cornering. All in all, I think it might have been better if I had left the stock rear bar?

Mine is also a 10AE. Of course, some of the oversteer could be due to the 18PSI boost Coldside? :)

[snakebit]

I'm not planning on using really sticky tires - the General Exclaim UHPs are just fine for my kind of driving. So I'm not seeing the kind of g forces you are. I do enjoy sliding the car a bit but not if it tends towards oversteer.

Power oversteer is of course available even with 10lbs boost, but I like the car to be neutral/slightly understeering when under a steady throttle.

Seems to be a consensus that the RB bar kit oversteers.

99mx5, who makes the the "sport" rear bar you're using?

[99mx5]

Its the factory Mazda sport package rear sway bar.

[jwalton]

Don't forget to consider adjusting your alignment as well. A little less negative camber up front and maybe a slight change in toe can have a dramatic effect on handling (try camber first). Not as cheap as adjusting tire pressures, but you don't have to worry about breaking stuff with stiffer sway bars.

[snakebit]

Don't forget to consider adjusting your alignment as well. A little less negative camber up front and maybe a slight change in toe can have a dramatic effect on handling (try camber first). Not as cheap as adjusting tire pressures, but you don't have to worry about breaking stuff with stiffer sway bars.
Ah, good point. I currently have the "Lanny" alignment specs w/ -1.2* front camber; he suggests -1.0 for slight understeer.

I'm also going to get a pair of heim endlinks and play with them before I change the bar. Seems to me that this is an inherently superior end link design, plus it enables me to mess with preload.

Any :eek: re. bar preload? Web research seems to indicate that it's generally not desirable, but I don't see why one couldn't dial in a little to make the bar effectively stiffer.

[snakebit]

Doh, I just thought about it and realized that sway bar preload will essentially raise one wheel while lowering the other - not good for anything but circle track! But I still like the heim links.

[snakebit]

I finally installed the RB 1.125" front bar. I like the balance very much w/ no rear bar. I might put the stock rear bar back on just to try it, but right now the car feels fairly neutral and much more settled in high speed sweepers.

As I recall, RB front and no rear is the setup preferred by many road racers.