How Much Padding Should I Expect From my Fibreglass Bucket Seat?
A Base Cushion Comparison Across Brands at GSM Performance
At GSM Performance, one of the most common questions we get from customers is: “How much padding do the seats really have?” It’s a great question, because when it comes to choosing the right bucket seat, comfort and seating position can make all the difference. To help answer this, we’ve taken in-store measurements and photos showcasing the base cushion thickness of fibreglass bucket seats from all the top brands we stock: Sparco, OMP, Mirco, Corbeau, and Cobra.
This comparison is designed to help you decide which seat brand or model may suit your needs best, whether you’re after maximum comfort or a lower seating position to improve headroom. We’ve lined up one representative seat from each manufacturer and recorded the thickness of the main base cushion to give you a clear idea of what to expect. Let’s break it down by brand.
Why Base Cushion Thickness Matters
When choosing a fibreglass bucket seat, the thickness of the base cushion isn’t just about comfort — it can directly affect your driving position, fitment in your car, and even your overall performance behind the wheel.
Thinner cushions are perfect for taller drivers who need every inch of headroom possible. In vehicles with tight cockpits or low rooflines — such as classic sports cars or kit builds — even a few millimetres can make the difference between a perfect fit and an awkward, cramped driving position. Seats from brands like Sparco and OMP are ideal in these situations, providing a slim profile that drops your seated height lower into the cabin. This can also improve your centre of gravity, a welcome bonus for performance-focused builds.
On the other hand, thicker cushions offer more comfort, making them a better match for drivers who spend longer periods of time in their cars. Whether you’re enjoying spirited road drives, attending regular track days, or running endurance events, thicker padding — like what you’ll find in Mirco, Corbeau, and Cobra seats — provides more support and reduces fatigue over time. These seats absorb more of the bumps and vibrations from the road, making them a practical option for dual-purpose or road-legal builds where comfort matters as much as control.
At GSM Performance, we believe that selecting the right cushion thickness plays a huge part in getting your seating position just right, which is why we’ve taken the time to measure and compare these options in detail, so you can make a choice that truly fits both your car and your comfort needs.
Sparco – The Slim-Line Racer’s Choice
Cushion Thickness: Approx. 40mm
Sparco’s fibreglass seats feature some of the thinnest base cushions we measured. This makes them a fantastic choice for taller drivers or for cars with limited headroom. The minimal padding allows for a lower seating position, which is essential in performance driving environments where helmet clearance is tight. If you’re running a track-focused build or need to sit as low as possible in your cockpit, Sparco is a solid option.
OMP – Similar to Sparco, with a Firm and Supportive Feel
Cushion Thickness: Approx. 55mm
OMP seats also come with relatively thin base padding, prioritising driver feedback and support. These seats are built for drivers who want to sit low and feel connected to the car — perfect for aggressive track day driving. OMP’s cushion material is firmer than most, adding stability without sacrificing support during high-G cornering.
Mirco – Comfort First, With Extra Base Padding
Cushion Thickness: Approx. 60mm
Mirco seats are known for their comfort. With thicker, softer base cushions, they are ideal for longer stints behind the wheel. If you’re racing in endurance events or simply want a bit of extra plushness on spirited road drives, Mirco delivers. Their dense foam padding provides more cushioning without sacrificing the bucket seat’s deep, supportive fit.
Corbeau – Added Padding for Road and Track
Cushion Thickness: Approx. 65mm
Corbeau seats come with generous base cushions, making them well-suited for both road and track use. Their seats are supportive but not overly firm, offering an excellent balance of performance and comfort. If you’re building a dual-purpose car that needs to keep you comfortable on the road but planted on the circuit, Corbeau’s fibreglass range is well worth considering.
Cobra – Adjustable with the Unique Pro-Fit System
Cushion Thickness: Varies (Low: ~35mm, Medium: ~60mm, High: ~75mm)
Cobra stands out by offering their Pro-Fit system, allowing you to tailor the base cushion height and feel to your liking. Whether you need a thinner pad for headroom or a taller cushion for added leg support and comfort, Cobra gives you that flexibility. This customisation feature is perfect for those who want a tailored fit — especially helpful for those sharing a seat with co-drivers or using it across different applications.
Final Thoughts – Choosing the Right Cushion for Your Driving Style
When it comes to selecting the perfect fibreglass bucket seat, it’s not just about looks or brand preference — the thickness of the base cushion can make all the difference to how a seat fits both you and your car. Whether you’re building a motorsport-focused track machine or a comfortable road-ready setup, understanding how cushion height affects driving position is key.
For those who need the lowest possible seating position, especially taller drivers with headroom limitations or those using tight cockpit builds, seats from Sparco and Cobra (when paired with the low Pro-Fit base cushion) are your go-to choices. These options offer minimal padding, helping to drop you deeper into the car and gain every millimetre of clearance.
On the flip side, if comfort is your top priority, particularly for road and track day use where longer stints behind the wheel are common, seats from Mirco and Corbeau are your best bet. These brands provide thicker, more cushioned base pads that help reduce fatigue and add a plush, supportive feel without sacrificing too much support.
No matter what your goal is, our hands-on seat comparisons and in-store photos aim to give you a realistic idea of what to expect, helping you make a more confident decision when selecting your next bucket seat from GSM Performance.