Expert Advice: Helmet Sizing Guide

There are plenty of bike helmet styles to choose from! Road cyclists, commuters and cross-country mountain bikers typically wear a shallower-fitting, lightweight helmet with good aerodynamics and lots of ventilation to help stay cool.

For trail mountain biking the best choice is an open-face trail helmet with extended coverage at the back of the head and temples. Trail helmets provide good ventilation at slow speeds for long, unrelenting climbs.

The risk of serious injury from downhill mountain biking is real. Wearing a gravity focused full-face helmet that offers the highest level of protection to your head, jaw and face is a no-brainer.

Enduro helmets are a fusion of downhill helmets’ protection with the ventilation and lightweight construction of trail helmets. Unavoidably, Enduro helmets are expensive. Skate-style helmets are popular with dirt jumpers, but also leisure cyclists and commuters for style and comfort reasons. Make sure the helmet is certified for cycling use (BS EN 1078 for adults, BS EN 1080 for kids; or the EU/US equivalent).

How to Select a Helmet Size

When selecting a helmet size, find a measurement range that your head circumference sits as close to the middle as possible. If you are between sizes for one style of helmet, consider alternative models or brands – sizing isn’t consistent between brands and many offer half sizing, such as M/L and L/XL. Use the sizing chart below to find suitable models and sizes.

What is a Good Bike Helmet Fit?

When worn with the fit system loose, a good-fitting helmet should have a little room, sit level on your head, and sit low enough to protect your forehead without obstructing your view.

How to Adjust the Helmet Fit

Tighten the fit system at the rear of the helmet. Adjust the straps so that the triangular harness yoke sits around the year and the buckles sit comfortably just below the earlobes. Tighten/loosen the chin strap buckle so that it rests comfortably beneath your jaw, applying light pressure. Move the pads on the inside of the helmet to fine-tune the fit. Finally, check that the helmet is secure.

Different Brands Fit Differently

It is worth noting that helmet shapes are unique to each brand. If you’ve struggled with finding a good fitting helmet in the past, we recommend visiting a GO Outdoors store and trying on a selection of helmets from different brands to gauge whether a particular brand gives a superior fit.

Can I Return a Helmet That Doesn't Fit?

No. For sanitary reasons, we only accept returns of bicycle helmets that are faulty. If you follow the advice above, you shouldn’t experience any problems with fit. If you are unsure, or have experienced fit issues in the past, we recommend visiting your local GO Outdoors store where you’ll be able to try a range of different options.