The Eibach E40-55-019-01-11 is a front-and-rear anti-roll kit for the ND-generation Mazda MX-5 Miata, sold as a matched pair of solid sway bars. The bars are built from precision formed hi-tensile steel alloy, cold-formed, tempered and shot-peened, and the bushings are greasable urethane. The stated gain is stiffer roll control in corners without giving up the car's balance. Choose this kit over stock bars when you want a flatter ride through fast transitions, and over a single rear bar when you want both axles tuned together. The 27mm front and 16mm rear diameters, plus the two-hole end-link adjustment on each bar, let you move the handling balance toward understeer or oversteer instead of accepting one fixed setting.
The manufacturer lists fitment for the 2016-2026 Mazda MX-5 Miata ND, the 2017 and later RF body, and the 2016-2020 Fiat 124 Spider base. Eibach also sells this bar as part of its PRO-PLUS package, which pairs it with PRO-KIT lowering springs. Owners on user forums say bars and springs share the work of controlling roll, so swapping only the bars may leave some handling gains unused. Keep the install in mind before buying: the manufacturer's ND instructions say the work should be done by a qualified mechanic, and forum owners call the front bar the harder of the two installs. Search terms that match this product include ND Miata 27mm front sway bar, MX-5 ND rear anti-roll bar kit, and Eibach PRO-PLUS Miata suspension.
The manufacturer lists the ND Miata for 2016-2026 and the RF ND for 2017-2026, so the same kit covers both bodies in those years.
The manufacturer positions the bars as part of its PRO-PLUS system alongside PRO-KIT springs. Owners on user forums note that roll control depends on both springs and bars, and some recommend changing both for the best result.
Each bar has two adjustment holes at the end links. Owners on user forums commonly run the front bar stiffer and the rear softer, which is the setup many use for spirited road driving.
This is a moderate-to-advanced suspension job, and the manufacturer's ND instructions say only qualified mechanics experienced with suspension removal should perform it. The sheet recommends a hoist with a screw jack, and it calls for removing the front wheels and the inner fender covers before the factory front bar comes out. The rear bar is lighter work, since the bushing brackets and end links are the main fasteners to remove. Lubricate the inside of the new bushings with the supplied grease before you install them, and tighten all hardware to factory torque. Owners on user forums say the front bar is the more awkward of the two, so allow extra time for end-link access. Recheck all fasteners after the first drive and plan an alignment check if you changed the ride height with springs at the same time.
