Skip to main content

Why road helmets don't work for mountain biking

Scott Centric helmet
What makes a road helmet comfortable at speed is exactly what makes it less than ideal off-road, if you crash
(Image credit: Cape Epic/Greg Beadle)

If you are a multi-discipline cyclist, the burden of gear duplication is real and expensive.

Would it not be great if you could use certain road cycling tech or commuter gear on your mountain bike? Or the other way around?

One of the most contentious equipment issues in cycling regards helmet choice. Why can’t you use the same version of this crucial bit of safety equipment on both a road and mountain bike? Surely all certified cycling helmets are graded to a similar safety specification?

Some riders might assume the cycling industry is attempting to profit by marketing dedicated road and mountain-bike helmets. But there are vast differences in terrain between on- and off-road cycling, which warrant a specific helmet design for each.

Let us evaluate what the road bike helmet is supposed to do. Beyond safety, there are two significant influences on road-bike helmet design: aerodynamics and ventilation.

For road cyclists, a reduced drag coefficient is valuable. Engineering a helmet which is shaped to be most aerodynamic, without compromising its safety rating, is a design destiny for road bike product planners.  

Road riders are also exposed to the secondary heat radiation produced by Tarmac, and therefore require the best possible ventilation profile through their helmet when riding. A mountain biker is hardly ever riding on a surface which is absorbing and then emitting heat with the intensity of Tarmac.

The result is that road bike helmets, for the interest of aerodynamics and airflow optimisation, appear minimalist in comparison to a mountain bike helmet. Less overall structure with huge ventilation ducts.

For mountain bikers, increased protection and adaptability are desirable features in helmet design. Mountain bikers are more at risk of crashing awkwardly, in terrain littered rocks, roots and all manner of strangely shaped nature. As a result, mountain bike helmets are heavier and feature more material, providing greater protection towards the base of the skull and top of the neck area.

Because mountain bikers ride at a lower general speed, aerodynamics aren’t as important. This is evident by the presence of visors on mountain bike helmets, which certainly are not aerodynamic. 

Visors are important, as they minimise sun flare in ravines and help manage vision in dappled light conditions, prevalent when riding deep forest trails. 

It is worth remembering that on a mountain bike, you are riding in a more upright position, which means sunlight has a greater influence on your field of vision than when on a road bike, where the posture is more aggressive and your eyes are often focussed on a fixed point directly ahead. 

Different helmets for different disciplines. Repurposing a road or commuter bike helmet for mountain biking will be a deeply frustrating experience, leveraging none of the inherent design benefits.

Lance Branquinho is a Namibian-born media professional who graduated to mountain biking after injuries curtailed his fascination with trail running. He has a weakness for British steel hardtails, especially those which only run a single gear. Rides: Morewood Kwela Cotic Simple 26 Pyga 160mm aluminium prototype