How to Size a Motorsport Helmet — NZ Fitting Guide
Aaron HarrisA motorsport helmet that doesn't fit correctly is less safe and less comfortable. Your helmet is a critical part of the safety and communications system, so getting the fit right matters. This guide explains how to measure your head, use the manufacturer's size chart, and assess fit.
Written by Aaron Harris, racing driver, race engineer and MotorSport NZ Licence Examiner. His licence-examiner role concerns licences, not certification or examination of helmets, racewear, FHR or HANS devices.
Step 1: Measure Your Head Circumference
Head circumference is the distance around your head at its widest point.
- Use a soft tape measure, or a length of string measured against a ruler.
- Position it just above the eyebrows.
- Run it around the widest part of your head, usually above the ears and across the back.
- Keep the tape level and note the circumference in centimetres.
- Measure twice and compare with the current size chart for the specific model.
A measurement is a starting point, not proof that a helmet fits your head shape.
Roux R1 SA2025 Size Chart
| Size | Head circumference |
|---|---|
| S | 56 cm |
| M | 59 cm |
| L | 60 cm |
| XL | 61 cm |
| XXL | 63 cm |
Confirm the latest manufacturer's chart for the exact R1 model and size. If between sizes, ask for fit advice before ordering rather than assuming the larger size is right.
Step 2: Understand Head Shape
Head circumference is only part of the equation. Head shapes vary from round oval to intermediate or long oval. Helmets of the same nominal size can fit differently across brands and models. Pressure on one area or gaps elsewhere may mean the shape is wrong; changing the number on the label will not always fix it.
Step 3: What a Correct Fit Feels Like
- Even, firm contact around the head without painful pressure points
- Minimal movement when you move your head or gently roll the helmet
- Clear sight through the visor, with the helmet seated in the intended position
- A secure chin strap and a comfortable cheek fit for the intended duration of use
Do not rely on the liner eventually compressing to resolve a painful pressure point. A loose helmet is not a safe way to solve tightness elsewhere.
Step 4: Cheek Pad Adjustment
Where the manufacturer offers compatible cheek pads of different thicknesses, these can fine-tune cheek fit, but cannot correct a fundamentally wrong shell shape or size. Ask us to check the pad version for your helmet before ordering. See Roux cheek pads.
Helmet Standards and Event Rules
Fit is essential, but it is separate from homologation and event eligibility. Check the exact helmet's Snell or FIA label against current MotorSport NZ Schedule A, Motorsport Australia and your series or event rules for your category. SA2025 is the current Snell motorsport standard in NZ and AU, subject to the applicable category and event requirements. A staff member's licence-examiner qualification does not approve or certify a helmet.
Get Fit Advice
Aaron can help you compare head measurements, models and the radio/intercom configuration you need. His MotorSport NZ Licence Examiner role is for licences only. Contact +64 27 449 9654 or aaron@harriscomms.co.nz.
Shop Roux R1 SA2025 Helmets
Frequently Asked Questions
How do I measure my head?
Use a soft tape just above the eyebrows and around the widest part of the head; record centimetres and check the model's current chart.
What if I am between helmet sizes?
Compare the exact model and head shape, and seek fit advice rather than automatically choosing a larger size.
Can cheek pads fix the fit?
Compatible pads may fine-tune the cheeks, but cannot correct the wrong shell shape or size.