KONI GTS COILOVER KIT FOR MAZDA MIATA ND

KONI GTS Coilover Kit

Street / Track Category

The MX-5 is already a very good driver's car from the factory, so the goal here isn't to completely change its character. It's to add spring and damping control for someone who is starting to ask more from the car while keeping it enjoyable on the street.

That's where we think the KONI GTS fits well. It's a good option for someone who regularly drives the car on the road but also does autocross, HPDEs or track days. A pretty typical use case would be running a good ultra-high-performance summer tire on the street and switching to a 200TW tire for events. The GTS gives you enough spring rate, damping control and ride-height adjustment to support that extra grip without turning the Miata into something you have to tolerate the rest of the week.

Damping

For street driving, we would generally start toward the softer side of the adjustment range and let the suspension move. The Miata doesn't need to feel stiff to feel good. Keeping some compliance helps the tire stay connected to imperfect pavement and keeps the car enjoyable on a normal road.

On the softer settings, the ride can stay surprisingly close to the factory Bilstein-equipped suspension even though the spring rates are higher. As you add damping, the car becomes more supported and communicative, which makes more sense when you're driving harder or using a stickier tire.

The adjustment is primarily rebound and is simple enough that the driver can actually learn from it. Make a change, drive the car and feel what it did. There are more sophisticated dampers with independent compression and rebound adjustment, but most dual-purpose Miatas don't need that level of complexity.

Springs, helper springs and future tuning

The standard GTS setup uses 350 lb/in front springs and 175 lb/in rear springs, roughly 62.5 N/mm front and 31.3 N/mm rear.

Those are fairly moderate rates for an ND coilover, which is one of the reasons we put this kit in our Street / Track category. There are much stiffer Miata setups available, and those can make sense as a car becomes more track focused, but the 350/175 combination gives the chassis noticeably more support without giving away the road manners that make an MX-5 enjoyable in the first place.

The GTS also uses standard 2.25-inch-ID linear springs. We like that because you're not locked into a proprietary spring. Manufacturers such as Eibach offer a wide range of 2.25-inch springs, so if the car or its use changes later, an experienced shop has options for changing rate as long as the replacement spring has the correct length and usable travel.

The kit also uses helper springs. These have very little working rate once the car is sitting at normal ride height, but they keep the main spring seated when the suspension is at full droop. That gives the installer more freedom when setting spring-perch position, including setups with little or no main-spring preload, without allowing the spring to become loose when the suspension unloads.

We don't recommend changing spring rates simply because it's possible. The spring and damper still need to work together. What we like is that the GTS gives you a sensible standard setup with some flexibility if the car becomes more specialized later.

Why we like the GTS

KONI has a long history in motorsport and adjustable dampers, but the bigger reason we like this kit is pretty simple: it gives you the adjustments most street/track owners will actually use without adding a lot of hardware and complexity they probably won't.

There are more expensive MX-5 suspensions with more adjustment and more competition-focused hardware. If you're building a dedicated track car and know exactly what you want from those extra adjustments, spending more can make sense.

For a lot of drivers, we'd rather see a good suspension like this on the car and leave money in the budget for tires, instruction, track entries and actually driving it. That's the type of product we want to focus on at 1W/car: enough capability to support the use case without selling someone equipment they don't really need.

1W/car Setup Recommendation

Just because the GTS is height adjustable doesn't mean the goal should be to lower the Miata as much as possible.

For a mostly street-driven ND, we generally like 15–20 mm lower than factory. For a car seeing more frequent track use, we'd move closer to 20–25 mm lower, with roughly 25 mm being about as far as we'd normally go on a dual-purpose car.

The lower center of gravity is useful, but lowering also changes the operating position of the suspension and reduces available bump travel. Go too far and you start requiring more spring and damping simply to deal with the travel you've taken away. The goal is to put the car at the height where it works best, not at the lowest setting the hardware allows.

The threaded spring-perch adjustment also allows an experienced installer to corner balance the car. With driver weight and a representative fuel load in the car, small changes at each corner can be used to improve cross weight and make the car more consistent between left- and right-hand turns.

Not every street Miata needs a corner balance, but if you're already installing adjustable suspension and regularly using the car at events, it's worth considering. Our preferred order is to set the ride height, corner balance if appropriate, and then perform the final alignment.

1W/car Autocross Setup

We also offer an optional Autocross Setup that keeps the standard 350 lb/in front spring but increases the rear rate from 175 lb/in to 225 lb/in.

The higher rear rate is intended to help the car rotate more easily in the tight corners and fast transitions typical of autocross. It moves the chassis toward a more neutral, rotation-friendly balance than the standard package.

The option adds $200 and includes the alternate rear springs.

We don't recommend the 350/225 setup for normal street use. The standard 350/175 package is the better choice for most street/track customers because it retains more rear compliance and a little more stability. If autocross is the priority, the 350/225 setup gives us a straightforward way to move the balance of the car in that direction without changing the entire suspension package.