Garment construction library
How racing suits are built: layers, panels, seams, closures and sizing, and what each construction choice is for.
Layer construction
How many layers a suit has, and why the number alone does not decide its protection.
Single-layer suits
One layer of fire-resistant fabric, typically a treated FR cotton twill. It is light and cool, and is the usual route to an SFI 3.2A/1 rating. Because a single layer leaves little insulating air, series that allow /1 suits often require fire-resistant underwear beneath them.
Proban® FR cottonTwo-layer suits
An outer shell and an inner layer, usually meta-aramid, with air trapped between them. The air gap does much of the insulating work, so two layers can reach a higher thermal rating than one heavier layer. This is the common construction for SFI 3.2A/5 suits.
Nomex® 2-layer suit systemThree-layer suits
An outer shell, an insulating middle layer and a comfort inner layer. The extra layer raises thermal protection, at the cost of weight and heat build-up in the cockpit. It is chosen where a series or discipline asks for higher ratings.
What decides the rating
Under SFI 3.2A the rating is based on the thermal protection of the material as tested, regardless of the number of layers, and underwear worn beneath the suit does not count. Under FIA 8856-2018 each component assembly must reach the minimum heat-transmission time. Layer count is a means, not the measure.
Standards explainedPanels, fit and movement
How the cut of a suit lets a seated driver reach, turn and brace without the garment pulling.
Box quilting
Stitching the layers together in a grid of boxes keeps them from shifting and holds the air gap evenly across the panel. Quilt size and pattern also change how stiff or soft the suit feels.
Radial and floating sleeves
A radial sleeve is cut in one piece with the shoulder, so the arm can reach forward to the wheel without lifting the body of the suit. A floating sleeve adds a gusset under the arm for the same purpose. Both are about freedom at the shoulder in a seated position.
Pre-shaped knees and elbows
Panels cut to the bent shape of a seated driver, so fabric does not bunch behind the knee or pull across the elbow.
Stretch panels
Knitted inserts, typically at the back, sides, crotch or under the arms, that let the suit move with the body. On fire-resistant suits the insert itself has to meet the same requirements as the rest of the suit: SFI 3.2A requires gusset material to reach the same minimum TPP as the suit.
Elastic waist and belts
A hidden elastic waist or an adjustable belt takes up slack at the waist, so a one-piece suit fits drivers of different builds without excess fabric.
Gussets
Extra fabric panels set into seams where the body needs room to expand, such as under the arm or at the crotch.
Collars, cuffs, seams and closures
Where a suit opens, ends or joins is where protection most often fails, so these details get the closest attention.
Collar construction
A soft, low collar seals against the balaclava and the head-and-neck restraint without rubbing. Collar height and closure are often specified around the helmet and HANS-type device the driver uses.
Cuffs
Knitted cuffs at wrists and ankles close the gap to gloves and shoes. SFI 3.2A requires cuffs at the wrists and ankles, made of fire-resistant material.
Seams and thread
Fire-resistant suits are sewn with heat-resistant thread, which SFI 3.2A tests separately. Seam type and stitch density affect both strength and comfort. On karting suits, seam strength is part of the tear and abrasion performance.
Zipper systems
SFI 3.2A requires zippers with metal teeth and fire-retardant tape, covered by fire-resistant material. Zipper position (central, offset or two-way) is a fit and comfort choice.
Leg cut
A boot-cut leg is wider at the ankle and covers the top of a race shoe, while a regular cut is straighter. The choice follows the shoes the driver wears and the series rules on overlap.
Branding methods
Embroidery, sublimation and printed transfers each behave differently on technical fabrics. SFI 3.2A permits embroidered logos. On FIA-homologated clothing, badges and their backing are part of the garment, so they must follow the manufacturer's homologated construction.
Sizing and made-to-measure
Grading a pattern across a size range, or cutting for one driver.
Standard sizing
Patterns graded across adult and youth size ranges. This suits teams, retailers and rental fleets ordering by size breakdown.
Size & measurement guideCustom sizing
A standard pattern adjusted for length, girth or sleeve, for drivers between sizes.
Made-to-measure
A pattern cut from the driver's own measurements, taken with the measurement guide and recorded on the order form.
Custom suit order form