Racing Safety Equipment Guide - Billy's Speed Shop

Safety Equipment Resource Centre

Racing Safety
Equipment Guide

Certifications explained, sizing charts, and technical guidance for RaceQuip suits, helmets and gloves, Simpson head restraints, and HANS devices.

RaceQuip

Suits, Helmets & Gloves

Simpson

Hybrid Restraints

HANS

Devices & Sizing

SFI / FIA

Certifications

SFI 3.2A Rated Suits Snell SA Helmets FIA Homologated SFI 38.1 Restraints

RaceQuip Sizing Guide

Suits, helmets, and gloves - how to measure correctly and pick the right size.

Important fit note - fire suits: RaceQuip suits are cut generously. If you are between sizes, go with the smaller suit. A suit that is too large will bunch up under your harness and reduce protection. A well-fitted suit moves with you and lies flat against the body.

Fire Suit Measurements

Measure in this order, using a soft tape measure. Measure over your fire-retardant underwear if you wear it.

Waist

At the natural waist, near the navel - not the hips where jeans ride.

Chest

Circumference at the fullest part of your chest, tape held level.

Inseam

Crotch seam straight down to the ankle bone.

Shoulder

Shirt shoulder seam to the opposite shoulder seam, across the back.

Sleeve

Base of neck to wrist, measured with elbow bent at 90°.

One-Piece Fire Suit Size Chart Inches

Size	Chest	Waist	Inseam	Shoulder-Shoulder	Sleeve
XS	34-36	28-30	28-29	16-17	31-32
S	36-38	30-32	29-30	17-18	32-33
M	38-40	32-34	30-31	18-19	33-34
L	40-42	34-36	31-32	19-20	34-35
XL	42-44	36-38	32-33	20-21	35-36
2XL	44-46	38-40	32-33	21-22	36-37
3XL	46-48	40-42	33-34	22-23	37-38
4XL	48-50	42-44	33-34	23-24	37-38
5XL	50-52	44-46	34-35	24-25	38-39

Helmet Sizing

Head circumference is the only measurement that matters for helmet fit.

How to measure your head

Use a cloth tape measure around the head approximately 1 inch (2.5 cm) above the eyebrows. Take the measurement twice and use the largest reading. If between sizes, go with the larger helmet. Add 1-1.5 cm if you use a head sock or balaclava. Use centimetres - they give finer resolution than inches.

Youth SFI helmets

Youth SFI helmets feature a smaller, lighter shell designed for lower-speed youth racing. Measure using the same method above. Hat sizes are only a rough guide - centimetre measurement is always more accurate.

Helmet Size Chart CM & Inches

Size	Circumference (cm)	Circumference (in)	Hat size (approx)
XS	53-54	20⅞-21¼	6⅝-6¾
S	55-56	21⅝-22	6⅞-7
M	57-58	22½-22⅞	7⅛-7¼
L	59-60	23¼-23⅝	7⅜-7½
XL	61-62	24-24⅜	7⅝-7¾
2XL	63-64	24¾-25¼	7⅞-8

Glove Sizing

Measure around the palm at the widest point, excluding the thumb. Measure your dominant hand.

Racing Glove Size Chart Inches

Size	Palm circumference
XS	Under 7"
S	7"-7½"
M	7½"-8"
L	8"-8½"
XL	8½"-9"
2XL	9" and over

Sizing charts are provided as a general guide. Fit may vary between product lines. RaceQuip suits are cut generously - when in doubt, size down for suits and size up for helmets.

Certifications & Standards

What the ratings on your safety gear actually mean - and what each sanctioning body requires.

What is SFI?

The SFI Foundation is a non-profit organisation that issues and administers performance standards for specialty and racing equipment. Products are submitted for independent scientific testing, and those that pass are permitted to carry an SFI tag.

Who mandates it?

Most race sanctioning bodies in the UK and US mandate specific SFI ratings as part of their rulebook. Always check the regulations for your specific series - the minimum required rating varies by class and event type.

Fire Suit Ratings - SFI 3.2A

How long the suit resists second-degree burns in a gasoline fire (1,800-2,100°F / 982-1,149°C). Numbers represent the ladder of thermal protection.

SFI 3.2A/1

≈ 3 seconds

Single-layer construction. Entry-level for circuit, oval, and drag racing. Suitable for lower-risk club and weekend competition.

SFI 3.2A/5

≈ 10 seconds

Multi-layer construction. Required by most serious sanctioning bodies. A significant step up. Nomex versions offer the best breathability.

SFI 3.2A/15

≈ 25 seconds

Professional-grade multi-layer. Required for NASCAR, IndyCar, and NHRA Pro Stock. Heavier and warmer to wear.

SFI 3.2A/20

≈ 40 seconds

Top-tier SFI specification. Used at the highest levels of American motorsport where maximum fire exposure time is a concern.

Glove ratings - SFI 3.3: Racing gloves are rated under SFI 3.3 (not 3.2A). The same tier system applies - SFI 3.3/1 is single-layer protection; SFI 3.3/5 is the most common requirement at club and professional level. Check your sanctioning body's rulebook for their minimum required glove rating.

Underwear - SFI 3.3: Fire-retardant underwear is also rated under SFI 3.3. Wearing certified underwear beneath your fire suit dramatically improves your Thermal Protection Performance (TPP). A 3.2A/1 suit worn over SFI 3.3 underwear can perform similarly to a standalone 3.2A/5 suit.

Helmet Standards - Snell SA vs SFI

Understanding the two main certification bodies for automotive racing helmets, and why SA matters.

Snell SA - current SA2025

The Snell Foundation is an independent non-profit that tests and certifies helmets. Snell SA standards exceed DOT, ANSI, and ASTM requirements. Testing covers impact, penetration, chemical resistance, fire resistance, and ease of removal. Snell purchases helmets from retailers to test - manufacturers cannot cherry-pick samples. Updated every 5 years.

SFI helmet ratings

SFI's own helmet certification for automotive racing use. Many sanctioning bodies accept either Snell SA or equivalent SFI rating. Both Snell SA and SFI SAH helmets include fire-retardant interiors, paint, and chin straps - a minimum requirement for all certified automotive racing helmets.

SA vs M ratings

An SA-rated helmet is designed for automotive racing and includes fire resistance. An M-rated helmet is for motorcycle use and may not include fire resistance. Never use an M-rated helmet in a race car if your regulations call for SA. Always check your series rulebook.

2017 SFI label change

From January 2017, the SFI label design changed for driver restraints, window nets, and roll cage nets. The old system used a punched-out month/year date of manufacture. New labels have a single pre-printed expiration date. Both remain valid - check the pre-printed expiry or count 2 years from the punched date on older labels.

Suit care: Dry cleaning is strongly recommended for all fire suits regardless of composition. Ongoing dry cleaning maintains fire retardancy - harsh detergents and machine washing can degrade fire-resistant fibres over time. Always inspect your suit before each use and replace if it shows wear, contamination, or damage to the SFI tag.

Motor racing is extremely hazardous. Safety equipment reduces risk but does not eliminate it. Always ensure your gear meets your sanctioning body's requirements and is inspected regularly. If an SFI tag is affixed to an item, that product met SFI Foundation specifications at the time of manufacture.

Simpson Racing - Head & Neck Restraints

The Simpson Hybrid and how to size, fit, and adjust it correctly.

About Simpson Racing

Simpson Racing has manufactured motorsport safety equipment since 1959. Their HANS-compatible helmet anchors, fire suits, gloves, shoes, and the Hybrid head restraint range are used at every level of motorsport from club racing to professional series.

The Hybrid advantage

The Simpson Hybrid uses a universal angle design that adjusts to fit different seat angles, making it ideal for instructors, drivers who use multiple cars, and anyone with a non-standard seating position.

Sizing the Simpson Hybrid - chest measurement

The Hybrid is sized by chest circumference measured below the pectoral muscles - not the widest chest measurement.

Below Pectorals

Wrap the tape measure around your chest below the pectoral muscles - not across the widest chest point.

In Your Suit

Measure while wearing your driving suit. If measuring without a suit, add 1 inch to your bare-chest measurement.

Tape Tension

Tape should sit against the body - not slack, not pulling tight. Take a relaxed breath and measure at rest.

Simpson Hybrid Chest Size Chart Inches - in suit

Size	Chest measurement (below pectorals, with suit)	Notes
Small	Under 36"	-
Medium	36"-40"	Most common fit
Large	40"-44"	-
XL	44" and over	Available on select models

Simpson Hybrid vs traditional HANS

Key differences in design and what application each is best suited to.

Simpson Hybrid

Adjustable angle fits all seat positions. Compatible with 3-point, 5-point, and 6-point harnesses, making it suitable for instructor use and multi-car drivers. Certified SFI 38.1 and FIA 8858.

Universal angle - no fixed angle selection required
3, 5, and 6-point harness compatible
Dual sliding front and rear tethers
Best for instructors, track day, multi-car use

Traditional HANS device

Fixed angle - 20° or 30° selected at time of purchase based on your seat angle. Requires a 5-point or 6-point harness. Preferred by dedicated race car drivers where seat angle is fixed. Certified SFI 38.1 and FIA 8858.

Fixed angle - 20° or 30° specified at purchase
5 and 6-point harness only
Dual sliding tethers
Best for dedicated race cars and professional series

Adjusting the Simpson Hybrid

All adjustments must be made seated in the car, in full kit - suit, undergarments, and helmet - with the harness fully fastened.

Shoulder belt position

Lap belts first, then shoulder belts. Adjust until the shoulder belts lie flat across your chest, with the adjusters mid-chest below the collarbone. Your shoulder belts should contact approximately one-third to two-thirds of the Hybrid's shoulder pad area.

Rear tether travel range

With chin horizontal (no downward head tilt), your helmet should be able to move forward a minimum of 1 inch and a maximum of 2¼ inches from its natural resting position. If travel falls outside this range, adjust the rear tether length until it is within specification. Have an assistant measure this while you remain seated and harnessed.

Chest strap position

The chest strap must sit below the pectoral line to prevent discomfort and reduce injury risk during an impact. If the strap rides up, it may contact the clavicle or throat in a frontal impact - refit the device before driving.

Head and neck restraints must be properly installed and adjusted before every session. Incorrect fitment significantly reduces their effectiveness.

HANS Device Guide

Sizing, angle selection, certification, fitment, and model comparison.

Why HANS?

The HANS device prevents basilar skull fracture - caused by the head continuing to travel forward after the torso has been stopped by the harness. It has been mandated by every major professional racing series including NASCAR, NHRA, IndyCar, and Formula 1 since the early 2000s.

How it works

A single piece resting on the driver's shoulders, HANS devices attach to the helmet via tethers that limit head travel in a frontal impact. The device moves with the torso, not independently, absorbing kinetic energy before it can reach the neck.

Choosing your HANS size

HANS devices are sized by chest circumference measured below the pectoral muscles, in your driving suit.

How to measure: Measure around the chest below the pectoral muscles - not at the widest chest point. Measure while wearing your driving suit. If measuring in street clothes, add 1 inch. Keep the tape snug but not tight. Drivers with heavily developed trapezius muscles may benefit from sizing up even if their chest measurement falls within range.

HANS Size Chart Inches - in suit

Size	Chest measurement (below pectorals, with suit)	Notes
Youth	Under 32"	Youth HANS III - lighter shell, SFI 38.1
Small	32"-36"	Available on select Pro models
Medium	36"-42"	Most common - fits the majority of adult drivers
Large	42" and over	Also for very broad-shouldered drivers

Angle selection: 20° vs 30°

The angle is determined by your seat and body position - not personal preference. Get it wrong and the device won't sit correctly against your shoulders.

20°

Standard / Upright seating

For most saloon, touring, and production-based race cars where the driver sits relatively upright. Seat angle typically 25° from vertical or less.

Saloon and touring cars
Drag racing
Rally (most applications)
Most HPDE and track day cars
Standard road car seating position

30°

Reclined / Formula seating

For more reclined seating positions - formula cars, sports prototypes, and also larger-chested drivers who need more clearance between the device and their chest.

Formula cars and single-seaters
Sports prototypes and GT3
Seat angle more than 25° from vertical
Larger-chested drivers needing chest clearance

Confirming your angle: Sit in your race car in normal driving position with harness fastened, HANS and helmet on. The HANS collar at the back of your neck must sit between 60° and 90° from horizontal. If the top of the collar points forward rather than backward, your device angle is too steep - switch to a more upright model (e.g. 30° to 20°).

Helmet attachment types

Post Anchor and Quick Click both perform identically in an impact. The difference is in how quickly and easily you can connect them.

Post Anchor

Helmet anchors thread through a post fixed into the M6 threaded inserts on the helmet. The tether clips over the post. More secure against accidental release, preferred by many professional drivers. Slightly slower to connect, especially with gloves on.

Quick Click

A spring-loaded clip that snaps directly onto the helmet anchor without threading. Faster and easier to connect, especially in tight cockpits. The red pull-string releases the clip for removal. Popular with drivers who share cars or enter and exit frequently.

Practice makes perfect: Practise the HANS attachment on your couch while watching TV - one side at a time, helmet on, relaxed. The second side is always harder than the first. Getting familiar with the motion in a low-stress setting means you won't struggle at the track.

HANS model comparison

Choosing between HANS III, IV, Pro Ultra, Pro Ultra Lite, and Youth models.

HANS Range Overview

Model	Material	Certification	Best for
HANS III	Injection moulded polymer	SFI 38.1 / FIA	Club racing, entry-level professional, best value
HANS IV	New polymer, redesigned legs	SFI 38.1 / FIA	Updated geometry, fits more seat angles, 10% lighter than III
Pro Ultra	Aerospace carbon fibre	SFI 38.1 / FIA	Professional and semi-pro drivers, significantly lighter
Pro Ultra Lite	Aerospace carbon, hollow core	SFI 38.1 / FIA	Absolute lightest - 100g+ saving vs Pro Ultra
Youth HANS III	Polymer, lighter construction	SFI 38.1	Young drivers - same protection in a smaller, lighter device

What is included with every HANS device?

Every HANS device ships complete with two helmet anchors (sufficient for one helmet), matching tether, and shoulder pads. Post Anchor and Quick Click versions are available - specify when ordering. If you have two race helmets, you will need an additional anchor kit for the second helmet.

Which helmets are compatible with HANS?

HANS devices require helmets with built-in M6 threaded anchor inserts. All Snell SA2015, SA2020, SA2025, and FIA 8859-2015 (or newer) homologated helmets include these inserts as standard. Older helmets may not be compatible - check inside your helmet for threaded metal inserts on either side of the ear area. Do not drill your own inserts.

Do I need to replace HANS tethers?

Replacement tethers and pads are available separately. Never use a device with worn or damaged tethers. Always inspect tethers before each event, and replace if they show fraying, kinking, or damage at the anchor attachment points.

HANS devices must be properly fitted and attached to your helmet before every session. Never drive without the tethers attached. The device does not provide protection unless correctly connected to both sides of the helmet.

Stilo Helmet Sizing Guide

Stilo produce helmets across three main ranges - ST5, Venti/WRC/Trophy, and Sport - each available in multiple shell sizes. Getting the right shell size matters as much as the right head size.

How to measure

Measure your head circumference approximately 1 inch (2.5 cm) above the eyebrows using a soft tape measure. Take the measurement twice and use the largest reading. Stilo helmets run traditionally a fraction smaller than other brands - if you are on the boundary between sizes, go up a size.

Shell sizes explained

Stilo use multiple shell moulds rather than one shell for all sizes. This means a medium head gets a smaller, lighter shell than an XL head - better weight distribution and a cleaner fit. The shell boundaries differ by range, so check the correct chart for your helmet model.

Stilo fit note: Stilo strongly recommend visiting an authorised dealer for an in-person fitting where possible. Helmets run slightly smaller than competitors at the same nominal size - if you are between sizes or usually size down, go with the larger size when ordering online.

ST5 Helmets - Full Face

Two shell sizes. Small shell covers XS to L; large shell covers L+ to XXXL.

ST5 Full Face Size Chart CM / Inches / US Hat

Size	Shell	Circumference (cm)	Circumference (in)	US Hat Size
XS	Small	54 cm	21-21¼"	6⅝-6⅔
S	Small	55 cm	21⅝-22"	6⅝-6⅔
M	Small	57 cm	22¼-22¾"	7⅛-7¼
L	Small	59 cm	23¼-23⅝"	7¼-7½
L+	Large	60 cm	23¼-23⅝"	7⅝-7¾
XL	Large	61 cm	24-24⅜"	7⅝-7¾
XXL	Large	63 cm	24-24⅜"	7⅝-7¾
XXXL	Large	64 cm	24-24⅜"	7⅝-7¾

ST5 CMR junior karting helmet: Available only in the small shell (narrower profile), covering sizes XS to L (54-59 cm). Not available in the large shell.

Venti WRC, WRX & Trophy Helmets

Three shell sizes - small, medium, and large - for better weight distribution across the full size range. Available in both full-face and open-face configurations.

Small shell

Covers XS to S (54-55 cm) in full-face. Covers XS to L (54-59 cm) in open-face.

Medium shell

Open-face models only. Designed for sizes L and XL (59-61 cm). Introduced for improved weight and comfort at mid-range sizes.

Large shell

Full-face: covers L+ to XXXL (60-64 cm). Open-face: covers XXL and XXXL (63-64 cm). Carbon, 8860, and Zero models now available in the large shell - a first for the industry.

Venti WRC / WRX / Trophy Size Chart CM / Inches / US Hat

Size	Full-Face Shell	Open-Face Shell	Circumference (cm)	Circumference (in)	US Hat Size
XS	Small	Small	54 cm	21-21¼"	6⅝-6⅔
S	Small	Small	55 cm	21⅝-22"	6⅝-6⅔
M	Small	Small	57 cm	22¼-22¾"	7⅛-7¼
L	Small	Small	59 cm	23¼-23⅝"	7¼-7½
L+	Large	Medium	60 cm	23¼-23⅝"	7⅝-7¾
XL	Large	Medium	61 cm	24-24⅜"	7⅝-7¾
XXL	Large	Large	63 cm	24-24⅜"	7⅝-7¾
XXXL	Large	Large	64 cm	24-24⅜"	7⅝-7¾

Stilo Sport Range

Two shell sizes - small covers XS to M, large covers L to XL. The Sport range uses a more relaxed internal lining compared to WRC helmets, giving a slightly roomier feel at the same nominal size.

Stilo Sport Range Size Chart CM / Inches / US Hat

Size	Shell	Circumference (cm)	Circumference (in)	US Hat Size
XS	Small	54 cm	21-21¼"	6⅝-6⅔
S	Small	55 cm	21⅝-22"	6⅝-6⅔
M	Small	57 cm	22¼-22¾"	7⅛-7¼
L	Large	59 cm	23¼-23⅝"	7¼-7½
XL	Large	61 cm	24-24⅜"	7⅝-7¾

Sport range fit note: The internal linings of the Sport range offer a more relaxed fit compared to WRC helmets. If you find WRC helmets slightly tight at your measured size, the Sport range may be a more comfortable alternative without needing to size up.

Carbon Curva 8870 Rib Protector

Sized by driver height and chest circumference - measured 5 cm below the armpits. Must be worn under the suit with the blocking system fully closed and belts fastened firmly.

Carbon Curva 8870 Size Chart CM

Part No.	Driver Height	Chest Circumference (5 cm below armpit)
AS0002XS	116-134 cm	58-68 cm
AS0002S	134-152 cm	62-72 cm
AS0002S+	134-152 cm	67-77 cm
AS0002M	152-170 cm	72-82 cm
AS0002L	170-188 cm	85-95 cm
AS0002L+	170-188 cm	90-100 cm
AS0002XL	170-188 cm	105-115 cm

Sizing the Carbon Curva: Where your height and chest measurements fall into different size bands, prioritise the chest circumference measurement. The device must close fully and the belts must fasten firmly - if there is any slack or the blocking system won't close cleanly, size down.

Do Stilo helmets fit differently to RaceQuip?

Yes. Stilo helmets run slightly smaller than many competitors at the same nominal size. If you normally wear a medium in a RaceQuip or other brand, you may find you need a medium or large in Stilo. Always measure your head in centimetres and use the Stilo size chart rather than converting from another brand's size.

What is the L+ size?

L+ is a Stilo-specific size sitting between L and XL at 60 cm head circumference. It exists because the shell transition from small to large happens at this point - L+ is the first size in the large shell. If you measure 59-60 cm you may find either L or L+ works depending on your head shape.

Which Stilo helmets are FIA homologated?

Stilo's WRC, WRX, Trophy, and higher-specification models carry FIA 8859 and/or FIA 8860 homologation. The ST5 range is available in both Snell SA and FIA homologated versions. The Sport range is typically SFI or Snell rated. Always check the certification label on the specific helmet you are purchasing - certifications can change between production batches.

Can Stilo helmets be used with a HANS device?

Yes. All Stilo racing helmets include M6 threaded anchor inserts for HANS tether attachment as standard. Post Anchor and Quick Click tethers are both compatible. If you are unsure whether your specific helmet has the inserts, look inside the helmet behind each ear - you will see a small threaded metal boss recessed into the shell.

Sizing data sourced from Stilo official sizing guide. Stilo recommend an authorised dealer fitting wherever possible. Shell sizes and availability may vary by model year and specific helmet variant.

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