Motorcycle Helmet Fitting Guide: How to Get Perfect Fit

Not sure which setup is right for you?

A helmet that doesn't fit properly won't protect properly. This is physics, not marketing. An ill-fitting helmet can rotate during impact, exposing your face and distributing forces unevenly. This turns a survivable crash into a life-changing injury. Getting the fit right is as critical as choosing the safety rating.

**Head Shape Reality (Why Expensive Helmets Don't Fit You):**

Human heads are not spherical. They're categorized into three basic shapes: round oval, intermediate oval, and long oval. Your head shape determines which brands will fit naturally and which will cause pressure points regardless of price.

Round oval: Equal dimensions front-to-back and side-to-side. Arai helmets typically fit rounder heads beautifully. If you're not round oval, an Arai will give you pressure points no matter how much you spend.

Intermediate oval: Slightly longer front-to-back than side-to-side. Shoei, AGV, HJC, and most brands target this most common shape. About 70% of people fit this category.

Long oval: Noticeably longer front-to-back. Scorpion and some HJC models suit longer heads. If you have a long oval head and buy an Arai, prepare for forehead and rear skull pressure that never breaks in.

Measure your head circumference (soft tape measure around forehead, just above eyebrows) for a starting size. But understand that circumference is just a starting point. Two people with 58cm heads can have completely different shapes requiring completely different helmets.

The In-Shop Fit Test (Actually Do These):

Put the helmet on. It should feel evenly snug all around your head. No pressure points digging in. No loose gaps. The padding should contact your entire head uniformly.

Cheek pads should press firmly against your cheeks. This feels weirdly restrictive when new. Your cheeks will compress slightly, and speaking will feel odd. This is correct. Loose cheek pads now means dangerously loose helmet after break-in.

The twist test: With the helmet on and strap fastened, try to rotate the helmet left and right whilst keeping your head still. The helmet should not move independently. If you can twist the helmet whilst your head stays put, it's too loose. Size down.

The roll-off test: Chin strap fastened, grab the back of the helmet and try to roll it forward off your head. A properly fitted helmet resists strongly. Your eyebrows will lift and your forehead skin will wrinkle before the helmet budges significantly. If the helmet rolls forward easily over your head, it's dangerously loose and could come off in a crash.

Break-In Reality (Buy Tight, It Gets Loose):

New helmet interiors compress 15-20% over the first 20-30 hours of wear. The foam padding that feels snug today will feel looser in a month. This is why a new helmet should feel slightly uncomfortably tight (without actual pain or pressure points) to account for compression.

If a helmet feels perfect and comfortable in the shop, it will be too loose after a month of riding. Either size down or swap to thicker cheek pads.

This creates a purchasing dilemma: buy the size that feels good now and have it become unsafe later, or buy the size that feels uncomfortably tight now and have it become perfect later. Choose tight. Your skull doesn't get a vote on this.

Pressure Points (These Don't Break In):

Actual pain or numbness indicates wrong shape, not wrong size. Pressure points focused on forehead, temples, or rear skull don't break in. They persist and worsen. Post-ride headaches suggest compression in wrong locations.

If you've tried multiple sizes of one brand and they all create pressure points in the same location, try different brands. Your head shape may simply not match that manufacturer's interior shape. No amount of break-in fixes shape mismatch.

Glasses Compatibility (Essential If You Wear Them):

Bring your glasses to helmet shopping. The temple arms must fit between your head and the cheek pads without creating pressure. Some helmets have dedicated channels for glasses arms. Others crush the arms against your head, creating pain within minutes.

Full-face helmets with glasses are genuinely awkward. You develop a specific insertion technique: glasses on face, helmet over head whilst carefully guiding temple arms through cheek pads without dislodging glasses. This becomes second nature after practice but never stops being mildly annoying.

Modular helmets solve this by allowing you to flip the chin bar up, put glasses on normally, then close the helmet. This convenience explains why many glasses-wearing riders pay the modular premium despite the safety trade-off.

Replacement Timeline (Yes, Really 5 Years):

Replace your helmet every 5 years regardless of visible condition. The EPS foam degrades chemically over time, losing protective properties. UV exposure from riding in sunlight accelerates degradation. A 6-year-old helmet that's never been dropped may look perfect but offers significantly reduced protection.

Replace immediately after any impact that involves your head hitting anything, even if there's no visible damage. The foam is designed to crush once, absorbing impact energy through permanent deformation. It looks fine because the damage is internal. It won't protect properly in a second impact.

If your helmet fit changes noticeably (feels looser than when new, moves on your head more than it used to), the padding has compressed beyond useful life. Replace it.

Yes, £300 every 5 years seems expensive. £60 per year for keeping your brain inside your skull seems reasonable when framed differently.

Our Honest Recommendation:

Buy your first helmet in a physical shop where you can try multiple sizes and multiple brands. Spend 30-45 minutes trying on at least 4-5 different options. Walk around the shop wearing your top choice for 10 minutes to check for developing pressure points. This is tedious. It's also how you avoid buying a £400 helmet that gives you headaches and doesn't protect properly.

Online shopping works brilliantly once you know your exact size in a specific model. "I wear Large in Shoei" doesn't mean you wear Large in AGV. Each brand sizes differently. Don't guess at fit for the equipment protecting your brain.

Not sure which helmet style suits your riding? Our quiz considers your typical use and narrows options before you shop.

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