If there comes a time that you need to actually use your helmet for something more than a style accessory - you dont want anything on the helmet that will cause the helmet to torque when it hits the ground. You want a rounded helmet that will hit the asphalt and bounce, not twist. If you have those cool pointy fins coming out of the back of your head - serving no real purpose because you dont bike nearly fast enough for that to make a smidgen of difference - you risk your helmet hitting the ground, fin first, torquing the helmet, twisting your head, and twisting your neck.
This is what is known as a bad idea.
Dont believe me? One of the great local unknown secrets is that the Bicycle Helmet Safety Institute is a WABA project. Here is what they say:
The goal of the helmet if used is to absorb as much of an impact as possible, resulting in the least amount of damage to your nut as possible. Any accessories on your helmet (fins, lights, cameras) increase your risk of neck and head injury. Forget the fins - they arent doing nothing. Get a nice rounded helmet.
|Bicycle Helmet Safety Institute|