If you’ve recently picked up an NA or NB, or you’ve been driving yours for years, you’ve likely noticed that the car doesn’t feel quite as “solid” as a modern hatchback. You hit a pothole or a mid-corner bump, and the whole car seems to shiver. That’s chassis flex in action. Without a fixed roof, the MX-5’s body often ends up absorbing forces that your suspension is supposed to handle. When the chassis twists, your suspension can’t do its job.
We put this kit together as an entry level upgrade for any serious build. Think of it as bracing the bones of the car before you start adding muscle (like power) or stiffer joints (like coilovers). It targets the three most common areas where the MX-5 tub gives way to flex: the front strut towers, the floor, and the doors.
Chassis Integrity Fundamentals Kit
What’s inside the kit:
- Reinforced Frame Rails – The factory floor rails are essentially thin “U” channels that are often crushed or rusted. Our rails wrap around them to provide a massive increase in longitudinal stiffness.
- 2 mm thick stainless steel for maximum strength and rust resistance.
- Extended design to brace a larger surface area than standard rails.
- Pre-drilled for a future butterfly upgrade brace if you decide to go even further.
- Practical extras: Includes 3 brackets for your brake lines and all stainless hardware.
- Weight: ~4.5 kg per rail – a fair trade-off for the structural gain.
- Front Strut Tower Brace – This connects the two front suspension points, which prevents them from leaning toward each other under hard cornering.
- Sharpens handling: You’ll notice the front end follows your steering inputs more faithfully.
- Construction: Heavy-duty steel with a powder-coated finish.
- Install: A true bolt-on part that takes minutes but makes a real difference in steering feel.
- Delrin Door Bushings – The doors on an MX-5 should act as structural members, but the factory rubber bushings are too soft to do that.
- 21 mm thick: We believe these are the thickest on the market, ensuring zero “gap” flex.
- 20° bevel: Carefully designed so you don’t have to slam your doors to get them to latch.
- Material: Tough Delrin that provides stiffness without the risk of cracking.
- Pro tip: A tiny bit of silicone oil on the metal cup makes these operate silently and smoothly.
Key benefits:
- Significantly reduced cowl shake and dashboard rattles on rough roads.
- Clearer steering feedback, as the front towers stay put during cornering.
- Protection for your floor pans from speed bumps or accidental high-centering.
- Consistent suspension geometry, making the car feel more predictable at the limit.
- A solid foundation that ensures future suspension upgrades actually perform as intended.
This kit is for you if:
- You are starting a build and want to do things in the right order (chassis first).
- Your car has high mileage and feels a bit “tired” or “floppy.”
- You plan on installing stiffer suspension and want to ensure the body can handle the extra load.
- You use your car for spirited driving or occasional track days and want more precision.
This kit is NOT for you if:
- You already have a full weld-in roll cage: A full cage does the heavy lifting for chassis rigidity, making these parts less of a priority for performance (though the frame rails still offer great floor protection).
- You want to keep the car 100% “soft”: If you enjoy the original, flexible feel of an early Mk1 and aren’t interested in performance driving, you might find the car feels a bit too “stiff” for your taste.
Fits all 1989-2005 models – NA (Mk1) and NB (Mk2).
Shipping worldwide.













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