TECHNICAL GUIDE — MK3 / NC
MX5 NC Seat Lowering — Full Guide
A tall driver's practical guide to the Jass Performance NC range — how to pick the right kit, install it without headaches, and see what it actually looks like once it's done.
The Mazda MX-5 NC offers the most headroom potential of all MX5 generations. Driving it daily at 197cm tall I designed these seat lowering kits — to solve the headroom issue once and for all, properly and relealing the full potential.
Whether you are looking to fit a helmet for a track day or simply want to stop craning your neck at every traffic light, here is the honest, practical guide to lowering your NC seats.
Which Kit Do You Need?
The NC changed seating geometry over its production life, and the parts are not universal. Here is the overview of the options.
4CM · 1.5" DROP
Height Adjustable Seats
If your driver's seat has the adjustment lever, this kit keeps that functionality while pushing the seat as low as the OEM rails allow — headroom increases from roughly 90.3cm to 94.3cm. In the NC, height adjustment was only ever fitted on the driver's side, so this kit is side-coded: order the LHD or RHD version to match your car.
View kit →1" OR 2.5" DROP
Non-Height Adjustable Seats
Two options: a 1" drop for a moderate, everyday improvement, or a 2.5" drop for maximum clearance — up to ~97.6cm of headroom. This is also the kit you need for the passenger seat, even if the driver's side gets the height-adjustable kit above.
View kit →Don't order two sets of the height-adjustable kit. Only the driver's side in most NCs has the height-adjustable base — the passenger side needs the non-height-adjustable kit. Since the 2.5" drop is fairly aggressive, we recommend the moderate 1" drop for the passenger side, to keep both seats visually and ergonomically balanced.
Our brackets are compatible globally, except for US-spec cars fitted with passenger-side occupancy sensors. If your car has an occupancy sensor (standard in US-market cars), standard lowering brackets will interfere with this safety system.
Installation Wisdom: It's All in the Details
I've seen hundreds of installations — some perfect, some... creative. Here is how to avoid the common pitfalls.
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The sound deadening is not optional
You must remove the thick black sound-deadening layer under the carpet where the rear seat mounts attach. If you don't, the bracket won't seat flat — the rail twists when you tighten the bolts, and the seat won't slide smoothly, or gets stuck completely.
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Respect the ball bearings
When you trim the rails, the plastic sliders and metal ball bearings can occasionally pop out. Don't panic. Re-insert them by positioning the outer rail carefully and tucking the edge in with a blunt screwdriver. A little thin oil helps. It takes patience, but it is standard practice.
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Metal on metal
Make sure the metal mounting points rest directly on the metal floor of the car. If the bracket rests on carpet or residual padding, it creates an offset — causing binding and stress on the rails.
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Grease is your friend
These are the lowest points in your cabin, and they collect condensation and moisture. Grease your bolts during installation to prevent corrosion and keep future adjustments effortless.
See the Results — Customer Builds & Video Guides
Sometimes seeing is believing. Here are real customer installs from the community.
Extra leg room in my MX-5 NC!
A full 1" bracket install on a Mk3, showing the real-world difference in legroom and driving position.
Lowering an NC2 OEM Recaro seat
A walkthrough specific to the Recaro-equipped NC2, useful if your car has the sportier factory seats.
Support FAQ
Based on internal support interactions — the most frequent questions I address.
- Can I lower both seats?
- Yes, but you must buy the correct kit for each. If you have a height-adjustable driver's seat, use the height-adjustable kit for that side and the non-adjustable kit for the passenger side.
- Why do my rails feel stiff after installation?
- 90% of the time this is because the mounting surface wasn't fully cleared (carpet or deadening left in place) or the bolts were tightened unevenly. Make sure everything is flush and perfectly aligned before final torque-down.
- Are the bolts the right length?
- The bolts are designed to clear the slider. If they feel too short, double-check you haven't left unnecessary washers in the stack. We provide high-tensile hardware — don't replace it with hardware-store bolts unless rated 10.9 or higher.
If you are stuck, read the manual once more — it contains the answers to 99% of the issues I see. We've designed these to bring the joy of the NC back to tall drivers. Enjoy the headroom!
