I never really realised how important some of those aerodynamic thingys were until coming home from the national rally. On the rear of my crash helmet is a vent. It has a nice plastic trim piece which somehow had become broken from on of its fixings allowing what seemed like a very small amount of movement. Sort it when I get home thinks I. Riding home at motorway speeds the effect was eyeball rattling causing blurred vision. All because above 65 the bit of vent started to flap about vigourously. This caused the whole helmet to destabilise.
Glued back into place very swiftly on arrival home. Will never doubt the wind tunnel testing again.

