How to Choose the Right Helmet Based on Your Head Shape
Why Head Shape Matters More Than You Think
Buying a motorcycle helmet isn't just about style or budget — fit is the single most critical factor in both comfort and safety. A helmet that doesn't match your head shape will create pressure points during long rides, reduce retention effectiveness in an impact, and ultimately make you less likely to wear it consistently. At GDM, we engineer our helmets for real riders, and that starts with understanding how the human head is shaped.
This guide breaks down the most common head shapes, how to identify yours, and what to look for when sizing a GDM helmet.
Understanding the Three Primary Head Shapes
Head shapes in the helmet industry are generally classified into three primary categories. Knowing which one describes you is the foundation of finding a helmet that fits properly.
1. Round Oval
A round oval head shape is nearly as wide as it is long when viewed from above — the head appears close to circular. Riders with a round oval head shape often find that standard helmets feel tight at the sides and loose at the forehead and back of the skull.
- Characteristics: Width-to-length ratio is nearly 1:1
- Common fit issue: Pressure on the temples and sides of the head
- What to look for: Helmets with a wider internal shell profile and generous cheek pad relief
2. Intermediate Oval
Intermediate oval is by far the most common head shape worldwide, and it is the shape that most mainstream helmets — including many GDM models — are designed around as their baseline. The head is slightly longer than it is wide, with a balanced, egg-like profile when viewed from above.
- Characteristics: Slightly longer front-to-back than side-to-side, roughly a 1:1.05 to 1:1.15 ratio
- Common fit issue: Generally, the most accommodating shape for standard sizing
- What to look for: Most GDM helmets will fit well out of the box; focus primarily on circumference sizing
3. Long Oval
The long oval is the opposite of round — the head is noticeably longer front-to-back than it is wide. This is one of the less common head shapes globally, but riders who have it often struggle the most with standard sizing because most helmets are not built with this extreme proportion in mind.
- Characteristics: Pronounced front-to-back length, narrow side-to-side width
- Common fit issue: Forehead and rear pressure, excess room at the sides
- What to look for: Elongated internal shell geometry; may require trying multiple models to find the right match
Additional Head Shape Considerations
Beyond the three primary classifications, there are a few additional characteristics that can affect helmet fit:
High Crown vs. Low Crown
Some riders have a higher vertical profile (tall crown) while others have a flatter top of the skull (low crown). A high crown can cause the top of the helmet liner to press down uncomfortably, while a low crown may result in excess space at the top of the helmet, reducing retention.
Wide Forehead or Wide Jaw
Asymmetries in facial width — a notably wide forehead or a wider jaw — can affect how the lower shell and cheek pads interact with your face, particularly on full-face models. This is where cheek pad thickness customization becomes important.
Prominent Occipital Bone
The occipital bone is the bony prominence at the base of the rear skull. Riders with a more pronounced occipital bone may notice pressure at the rear of the helmet's liner. If you experience this, it's typically addressable by sizing up one increment and using thicker rear liner pads.
How to Measure Your Head Correctly
Before referencing any GDM size chart, you need an accurate head circumference measurement. Follow these steps:
- Use a flexible fabric measuring tape (a tailor's tape, not a metal ruler).
- Place the tape approximately one inch (2.5 cm) above your eyebrows at the front, running it above the ears and around the widest part of the back of your skull.
- Keep the tape level — do not angle it up or down.
- Take the measurement two to three times and use the largest consistent reading.
- Record your measurement in both centimeters and inches, as size charts vary by region.
Once you have your circumference, cross-reference it with GDM motorcycle helmets size chart. Do not assume your size is consistent across different helmet brands.
The Neutral Fit Test
Measuring your head gets you to the right starting point, but the only true test of fit is wearing the helmet. When you first put on a GDM helmet, perform this neutral fit check:
- No gaps: The liner should be in contact with your head all the way around — forehead, crown, rear, and sides — with no void spaces.
- No pressure points: Firm, even contact is ideal. Isolated pressure at any single point (especially the temples or top of the skull) indicates a shape mismatch, not just a size issue.
- Cheek pad contact: On full-face models, your cheeks should be gently compressed by the cheek pads — not painfully squeezed, but noticeable. This will relax slightly as the pads break in over the first 15–20 hours of use.
- The roll-off test: Fasten the chin strap and attempt to roll the helmet forward off your head. It should not roll off. If it does, the fit is too loose regardless of the size label.
GDM Helmet Fit Philosophy
Every GDM helmet is engineered with an intermediate oval baseline, but our liner systems are designed to accommodate variation. Adjustable cheek pad thickness and crown liner inserts allow riders to fine-tune the fit without changing helmet size. If you're between sizes or your head shape deviates from intermediate oval, these liner adjustments are your first tool — not a size change.
If you're still unsure after measuring and testing, reach out to our team directly. We'd rather spend five minutes helping you find the right fit than have you ride in a helmet that doesn't perform the way it was designed to.
Quick Reference: Head Shape Summary
| Head Shape | Profile (Top View) | Most Common Fit Issue | GDM Recommendation |
|---|---|---|---|
| Round Oval | Nearly circular | Side/temple pressure | Try wider-profile shell; adjust cheek pads |
| Intermediate Oval | Slightly elongated | Generally accommodated | Standard sizing; follow circumference chart |
| Long Oval | Noticeably elongated | Forehead/rear pressure; side gaps | Test multiple models; focus on liner contact |
At GDM, we engineer our helmets for real riders, and that starts with understanding how the human head is shaped. Every GDM helmet is engineered with an intermediate oval baseline, but our liner systems are designed to accommodate variation. Adjustable cheek pad thickness and crown liner inserts allow riders to fine-tune the fit without changing helmet size.
If you're shopping for a new helmet, explore our full motorcycle helmets collection to find models engineered for your head shape. Whether you're looking for motorcycle helmets with Bluetooth or, a specific style like the Demon, Ghost2, or Raptor, checkout our complete lineup.
Ride safe. Fit matters. — The GDM Team
