Ordered an Aerohead in Large. "Need" a Medium

Triathlon Forum
1

Here in the UK the Giro importer is infamous for limited stock
Aerohead in Medium has been out of stock for ages, and not due in until October !
I ordered a Large instead to see what the fuss was about (and see how much the sizes overlap)
It actually feels okay on - but looks huge on my head !

Here is a question; whats the aero disadvantage on sizing up? Is it modest; or enough to return this and choose another model completely?

2

difficult to know… probably some though.

Difference between a medium and a small S-works TT was 3 watts for me. But that’s n=1 on a different helmet design, so ¯_(ツ)_/¯.

3

Thanks
I have a Kask Bambino in a Medium and thats tiny on (feels comfy though)
But the ‘mirror test’ is that the Kask seems 2/3 of the size on !
But I fully appreciate that does not represent how the wind hits each of them etc etc