Stilo ST6 F Composite motorsport helmet - helmet fit and sizing guide - Harris Race Radios NZ

Helmet Fit & Sizing Guide

Harris Race Radios Team

Helmet Fit & Sizing Guide — Motorsport Helmets Only

A properly fitted motorsport helmet is the single most important factor in driver safety and comfort. A $2,000 helmet that fits poorly is less safe than a $500 helmet that fits correctly. As professional race, comms, and data engineers, we've fitted thousands of helmets across circuit racing, rally, endurance, off‑road, Speedway, and Lemons racing. This guide explains how to get the perfect fit for brands like Stilo, Bell, Schuberth, Roux, Xron, MRC, Impact, and Pyrotect.

1. Why Helmet Fit Matters

  • Safety — A loose helmet can rotate or lift in an impact.
  • Comfort — Pressure points cause headaches and fatigue.
  • Noise — Gaps increase wind and engine noise.
  • Comms clarity — Padding density affects microphone performance.
  • Fatigue — A well‑fitted helmet reduces neck strain.

Motorsport helmets are designed to fit snugly. If you're used to motorcycle helmets, motorsport helmets will feel tighter — this is normal and necessary.

2. How to Measure Your Head Correctly

  • Above the eyebrows
  • Around the widest part of the head
  • Level around the back of the skull

Record the measurement in centimetres. This is your starting point for sizing.

Important: Different brands fit differently even at the same size. Always try the helmet on or consult our expert team.

3. How a Properly Fitted Helmet Should Feel

  • The helmet should feel snug but not painful.
  • Your cheeks should be pushed in firmly — like pressing on your gums.
  • You should not be able to rotate the helmet independently of your head.
  • No hot spots or sharp pressure points after 5–10 minutes.
  • The crown (top) should make full contact with your head.

If you can shake your head and the helmet moves separately, it is too big.

4. Common Fit Mistakes We See Every Week

  • Buying too big — the #1 mistake.
  • Choosing by hat size — completely inaccurate.
  • Not wearing the helmet long enough — pressure points appear after 5–10 minutes.
  • Ignoring head shape — round vs oval matters.
  • Assuming all brands fit the same — they don't.

5. Brand‑to‑Brand Fit Differences

  • Stilo: Neutral‑oval fit. Works for most drivers.
  • Bell: Round‑oval. Great for wider heads.
  • Schuberth: Intermediate‑oval. Very stable at speed.
  • Roux: Slightly narrow. Good for slim head shapes.
  • Impact: Round‑oval. Popular in Speedway and off‑road.
  • Pyrotect: Neutral‑oval. Good value and versatile fit.
  • Xron: Neutral entry‑level fit for Speedway and Lemons.

6. Cheek Pads, Crown Pads & Custom Fit Options

  • Thicker or thinner cheek pads for comfort and stability.
  • Crown pad adjustments for height and pressure.
  • Stilo and Bell offer the widest range of fit tuning options.

We can supply and install all fit‑adjustment components.

7. Fit Testing Procedure (Used by Race Teams)

  1. Put the helmet on by pulling the straps apart and rolling it over your head.
  2. Fasten the chin strap firmly.
  3. Shake your head side‑to‑side and up‑and‑down.
  4. Try to rotate the helmet — it should not move independently.
  5. Wear it for 5–10 minutes to check for pressure points.
  6. Simulate race posture — seated, looking forward, hands on wheel.

If you feel pain or pressure after 10 minutes, the helmet is the wrong size or shape.

8. When to Replace Your Helmet

  • Every 5–10 years depending on FIA/Snell standard.
  • After any significant impact — even if no cracks are visible.
  • If the liner has compressed and the helmet feels loose.
  • If scrutineers reject it due to age or condition.

Need Help Finding the Right Fit?

We are qualified race, comms, and data engineers. Tell us your head measurement, racing type, and preferred brands — we'll match you to the perfect helmet.

Ask a Helmet Expert

About the Author

Harris Race Radios Team — New Zealand & Australia's professional motorsport equipment specialists since 1975. Our team includes Aaron Harris, an internationally experienced racing driver and race engineer (Barcelona 24 Hour — 1st in Class 2013; Bathurst 1000 & 12 Hour competitor; BMW Race Driver Series Champion 2011; race engineer for Earl Bamber Motorsport, TekworkX, Matt Stone Racing, and Porsche Carrera Cup Australia, Asia‑Pacific & New Zealand), and Rex Harris, a qualified Radio Telecommunications Engineer and approved Radio Certifier for both New Zealand (RSM) and Australia (ACMA). Aaron is also an MSNZ Licence Examiner for helmets, racewear, and FHR/HANS devices. Read more about us →

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