Miata koni sport/GC spring rate advise

Trying to figuar out what spring rate I want to run on my 95 Miata. I have new koni sports and will be purchasing Ground control coilover sleeves/springs

The car will be used mostly for tearing up back roads with maybe a track day and a couple autoxs here and there.

Id really like to run a 450f 300r setup but I fear 450 might be a little much for the konis and make the car feel shaky on back roads but would like to hear what others have to say

thanks -Jeff

I'm running Koni yellows and Ground Controls on my Miata- have been for about 5 years now. Rates are 550F/375R and I've not had any complaints about the ride nor the performance. Mine is a '90 with stock sways and 15x7s wrapped in Star Specs. It sees street driving, autocross and the occasional trip to Deal's Gap.

how does it feel when youre driving it hard on less than perfect roads ? Id like to run as stiff as a spring as I can and still feel the konis have control over whats going on

The standard rates are 375/250. It's a pretty good all-around compromise. I've always felt the Konis are happiest with stock spring rates myself unless they've been revalved.

The Flyin Miata VMAXXs I'm running are 391 lb/in in the front and 258 lb and they took the abuse of the top section at Mt. Ascutney well. The Spec Miatas couldn't claim as much - I think some of them were missing fillings after a few runs.

Powar wrote: I'm running Koni yellows and Ground Controls on my Miata- have been for about 5 years now. Rates are 550F/375R and I've not had any complaints about the ride nor the performance. Mine is a '90 with stock sways and 15x7s wrapped in Star Specs. It sees street driving, autocross and the occasional trip to Deal's Gap.

so it doesnt feel like your bouncing all over the place ?

I run Koni Yellows with 450/300 GCs, a Racing Beat hollow front bar and no rear bar.

The 450 number was what some Koni engineer was quoted as saying is the max the yellows can handle. Everything else just followed.

It was designed primarily for track days, without being unstreetable. Definitely more agreeable than the Spec Miata kit on the road, but when you hit a pothole or sharp expansion joint, you know about it.

I like the setup pretty well, and others have said the same thing.

peter wrote: I run Koni Yellows with 450/300 GCs, a Racing Beat hollow front bar and no rear bar. The 450 number was what some Koni engineer was quoted as saying is the max the yellows can handle. Everything else just followed. It was designed primarily for track days, without being unstreetable. Definitely more agreeable than the Spec Miata kit on the road, but when you hit a pothole or sharp expansion joint, you know about it. I like the setup pretty well, and others have said the same thing.

how many miles on this setup and how are the konis holding up ?

anyone else ?

I have Konis with 350 front/250 rear spring rates on my '92 Miata. I also run a Racing Beat front bar and stock rear bar. Jay at Ground Control picked these rates for me. It's basically a street car that sees some autocross.

AllSystemsNominal wrote: how many miles on this setup and how are the konis holding up ?

Not very many, probably less than 2k. Car doesn't get driven much, but when it does, the Konis seem just fine.

I have what I assume are the standard rates on mine and want to stiffen. How can I confirm the rates, are they printed on the spring? (would rather avoid having to take them off and measure)

What are the diameters and lengths of the standard setup?

Thinking about trying the 550/375 setup if I can put whats on the front on the rear and just get 2 springs.

Want to reduce my body roll for some more ultimate grip, faster transitions would be a bonus too! Also stiffer relative to the rear might let me remove the rear bar for better traction (open diff for STS)

Setup in that pic is "standard" GC with koni yellow, RB hollo front bar (mid setting), stock rear, 205 RE-11's

Feels good on the street, only time its harsh is over something like bad railroad crossings or big potholes. The shocks feel a bit bouncy at full soft setting, but good at 25% or more. I generally run them at about 75% as they have good response on the auto-x course with that. Havent put much time into playing with the shock settings yet, bigger fish to fry.

For street, I dont feel that stiffer then this would be a problem. It is a light car, furthermore a sports car, so you expect some harshness. It is quite comfy where it is.

Eibach springs have the rate, length and diameter printed on them.

0600.250.0375 is a 375 lb spring that is 2.5" in diameter and 6" long. That's the standard front spring for a Koni setup on a Miata. Standard rears are 0700.250.0250.

There's a metric version as well, but the only change is the units. The position is the same.

If you want to reduce body roll you might want to look at sway bars instead.

I already have the largest RB front bar, which is among the stiffest on the market.

Nice thing about STS is that many of the good national level guys share their setups, including Canak (natl champ).

When I have the same (stiff) bar they do (or stiffer then some of them), but about half the spring rate I see all of them running (700/450 with revalved front shocks) I think there is more to be done with springs.

Other thing is that the mounts for the front sway are kinda weak for big bars with limited options to reinforce them within STS rules.

Another factor is that STS dosn't allow a LSD on my car (1.8), so a rear bar can exacerbate problems with spinning the inside rear in a turn under throttle.

Thanks for the info on reading those springs Keith!