What is the easiest free way to gain headroom in the MX-5 ND?

Removing the backrest tensioning springs is the quickest and most effective free modification. It allows the backrest to lean back approximately 80mm, providing around 20mm of perceived headroom gain. Fully reversible and takes about 10 minutes.

What does disconnecting the height adjustment rack do in the MX-5 ND?

It locks the front of the seat base in its lowest position, allowing the body to dive forward for 15–20mm of headroom gain. The modification is reversible but should be paired with significant rear seat lowering to maintain the seat angle and prevent forward slippage in a crash.

Is trimming the seat foam (foamectomy) reversible?

No. Trimming foam from the inside of the seat back side bolsters is non-reversible. It is essential for drivers using the 58mm lowering rails or fixed adapters in the lowest position, as tall drivers with larger chest breadth will otherwise be prevented from sitting fully into the lowered position.

What is the best seat lowering combination for a very tall MX-5 ND driver?

For maximum headroom: start with the DIY modifications (remove base tensioners, disconnect height adjustment rack, remove backrest tensioning, trim foam), then add 48mm or 58mm sliding rails for maximum drop, and pair with the seat back raising kit to maintain correct seating angle.

What is the difference between the fixed adapters and sliding rails for the MX-5 ND?

Fixed adapters lower the seat 56mm and produce a flatter rake angle — better for drivers with shorter legs, heavier builds, or helmet use. Sliding rails lower the seat 33–58mm while retaining full fore/aft adjustment, but the rail mechanism adds height at the front, creating a steeper rake angle that suits longer-legged drivers. The 58mm Extreme rails are for drivers above 193cm.

Do the free DIY modifications work alongside the Jass Performance seat lowering products?

Yes. All four DIY modifications are compatible with and complementary to the Jass Performance lowering rails and fixed adapters. They work best in combination — the hardware provides the primary seat drop, while the DIY modifications further optimise headroom and comfort.

MX5/Miata ND Seat Lowering Potential

Original article published 07.07.2023 — This guide represents months of real-world testing and development on customer vehicles. Latest edit: 01.06.2026.

The Mazda MX-5 ND is a brilliantly balanced car — except for one thing: headroom. If you're above 6 feet, the factory seat position feels tight. This guide covers every method to lower the seating position, from free tweaks to bolt-on kits, and how to combine them for maximum effect.

Quick Reference: All Methods

Method	Lowering	Reversible	Difficulty	Cost
Remove base tensioners	Minimal	Yes	Easy	Free
Lower seat base front	~15–20mm	Yes	Easy	Free
Remove backrest tensioning	~20mm perceived	Yes	Easy	Free
Trim backrest supports foam	~10mm	No	Moderate	Free
Fixed adapters	56mm (4 positions)	Yes	Easy	£
Sliding rails	33–58mm	Yes	Easy	££
Seat back raising kit	+50mm rear	Yes	Easy	£

DIY Modifications (Free)

1. Remove Seat Base Tensioners

The simplest first step. Removes factory over-tensioning.

Lowering Effect

Minimal

Reversible

Yes

Difficulty

Easy (5 min)

How:

Remove the two base tensioners on the underside of the seat frame. You'll feel the seat drop slightly once installed back in the car. The side ones are easily detached with flat screw driver and a hammer tap.

Base tensioners removed

2. Lower Seat Base Front (Height Adjustment Rack Disconnect)

Detach the height adjustment mechanism at the front. This allows the seat to "dive" forward, moving your head forward and down simultaneously — very effective for headroom.

Lowering Effect

~15–20mm

Reversible

Yes

Difficulty

Easy (15 min)

How:

Remove the two side bolts holding the seat frame, pull the front frame outward, disconnect the height adjustment rack, and reassemble. The seat front will be locked in a lower position; you'll lose height adjustment but gain 15–20mm of lowering.

Rack disconnect shown

Video:

Safety Note:

This mod should ideally be paired with significant rear seat lowering to maintain the seat's angle and prevent forward body slippage in a crash.

3. Remove Seat Backrest Tensioning

Factory tension springs prevent the backrest from reclining fully. Removing them allows the backrest to lean back ~80mm, giving ~20mm of perceived headroom gain and improving comfort to tall drivers (above 190cm or 6'1"). These measures are to create room, comfort is subjective and differs for each body build.

Perceived Gain

~20mm headroom

Reversible

Yes

Difficulty

Easy (10 min)

Result:

Significant improvement in space and back support. Backrest now leans back naturally, and you'll have more room overhead.

Before tensioning removed

Tensioning springs location

Full recline achieved

4. Trim Seat Foam (Foamectomy)

Carefully trim the foam padding from the inside of the seat's side bolsters.

Clearance Gain

~10–15mm

Reversible

Difficulty

Moderate (30 min)

Important:

This is a MUST for anyone using 58mm lowering rails or fixed adapters in lowest position. Tallest drivers or the very big ones have significantly larger chest breadth, and the side bolsters will be in the way otherwise.

How:

Carefully trim foam from the inner edges of the side pads. Maintain the seat's shape while improving clearance. Work slowly and test fit frequently.

Foam trimmed for clearance

Jass Performance Products

Seat Lowering Adapters (Fixed)

Bolt-on, reversible
Lowers by 56mm total
Four preset positions (25mm spacing)
Height positions in 5mm steps possible with optional fine drop adjustment kit
Easy installation — access to all four bolts
Works with OEM seat rails

Best for: A fixed solution. Not so-tall-drivers or the ones who need to fit in with helmet - the reason is that, the rake of the seat base is lower than the slider rails version, due to the height of the rails not added to the front. Once installed, your seat is locked at one height. Good for drivers who've found their ideal position.

Seat Lowering Rails (Sliding)

Bolt-on, reversible
Lowers by 33–48mm (fully adjustable)
Full sliding functionality — move front to back freely
Height positions in 5mm steps possible with optional fine drop adjustment kit
Compatible with ND and Fiat Spider seats

Best for: Maximum flexibility. Adjust both height and fore/aft position. Premium option for drivers who want full control.

Seat Extreme Lowering Rails (Sliding)

Bolt-on, reversible
Lowers by 58mm
Limited sliding functionality to the front compared to OEM
Suitable for drivers above 193cm (6'3") with legs to profit from the added base rake
Compatible with ND and Fiat Spider seats

Best for: Tallest drivers up to 200cm (6'7") as of the available headroom. Premium option for drivers who NEED full drop.

Seat Back Raising Kit

Reversible
Raises rear of seat by 50mm
Improves ergonomics, side support, seat belt routing
Better headrest and speaker positioning

Best for: Pairing with 48/58mm lowering kits in their lowest positions.

How to Combine These

The real expertise is knowing which modifications work together. Here are recommended combinations:

For Maximum Headroom and flexibility (Tall Drivers)

Start with DIY: Remove tensioners, lower front base, remove backrest tensioning, trim foam
Add sliding rails: Install 48/58mm lowering rails for maximum drop. Consider the fine drop adjusment kit for rake adjustment.
Balance with raising kit: Add seat back raising kit to keep seating angle comfortable and safe

For Tall Drivers, best for Average Drivers and Racing with Helmet

DIY foundation: Remove tensioners, lower front base, remove backrest tensioning
Add fixed adapters: 56mm bolt-on adapters for proven, stable lowering. Consider the fine drop adjusment kit for rake adjustment.
Balance with raising kit: Add seat back raising kit to keep seating angle comfortable and safe
Optional foam trim: Only if side bolster contact is noticeable

For Minimal Investment

Just DIY: Base tensioners + base drop + backrest tensioning
Cost: Free, 30 minutes work
Best for: Testing before committing to products

Safety Reminder:

Any significant lowering changes how your body sits in the seat during hard cornering or braking. Test thoroughly on a safe road before track use. Consider the raising kit to maintain seating angle if needed.

Next Steps

Explore all MX5/Miata/Fiat Spider lowering solutions here.

Still not sure which option suits you? See the full decision guide →

Questions? Get in touch — we've fitted these to hundreds of tall drivers.

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