[volcomstoner21]

I have never been able to fiind out what the thing on the back of racers jackets are called. The cone like looking things behind the helmet. Or does it even have a name. Weird quiestion but just one that I randomly think of. thanks guys.

 

[TOMIMOTO]

The speed hump thingy for aerodynamics?

 

[volcomstoner21]

Yep. Is that what its called. speed humpy thing.

 

[steelrain]

It is called a areodynamic wedge, areodynamic speed hump or speed hump.

Basically like the draft plates on AMA, WSBK, and MotoGP bikes it helps to break up the flow air behind the rider and bike, making it very difficult to "draft" a rider in the straights if you are more than a few inches away.

It has very little if anyhting to do with your areodynamics.

 

[eRRoc]

it also creates a bridge between the ground and your back during a fall...so a bit of a safety thing as well

 

[raptor]

... it helps to break up the flow air behind the rider and bike, making it very difficult to "draft" a rider in the straights if you are more than a few inches away.

It has very little if anyhting to do with your areodynamics.

Now there's a load if I've ever heard it. Read up on a somthing called the "Coanda Effect":

The shape and positioning of the bump behind the riders helmet helps reduce recirculation in behind the helmet. It smooths out the flow by providing a suface for the air moving past the helmet to align itself with. This helps increase the base pressure behind the helmet, thereby reducing pressure drag. The same reasoning goes into the Haya having such a huge ass!!! Straight line speed!

Woah. Think I blacked out for a second there - feel like Will Ferrel in Old Skool...

 

[NewRedRider]

Raptor is correct. The speed hump is there to reduce the lower pressure point behind the riders helmet much like the aerodynamic pieces they put on the top of semi rigs. It doesn't allow the air to create a low pressure by filling in the void. It is purely for aerodynamics. Safety is just a secondary effect if any.

Now, how that speed hump affects rider drafting, I can't say for sure. It probably does reduce the draft for the rider behind you because it reduces the low pressure which causes the "draft".