What is the purpose of this part on vintage brakes?
 

The little wings on the brake pads.
http://bikeforums.net/attachment.php...hmentid=180862

To facilitate quicker wheel insertion. They're guides.

They are guides for reinstalling the wheels w/o getting the tires hung up on the brake shoes.

Their there to make your bike look faster and to make other people wonder what their for.

New bikes have them too sometimes.

Thanks for the info.

They also assist in setting the brake pad clearance from the rims - I grip them tight onto the rim, pull the brake cable tight, tighten the cable bolt, and release them. Usually there is enough slack in the system that the pads will just clear the rim without requiring further adjustment.

In the front they act like wings to assist in steering. In the back they assist in keeping the bike straight and induce a little downforce due to their angle.

I asked that too, several months ago, and I was made to figure it out...

You! You get an answer right off the bat!

Not fair!

They're cooling fins to help keep the pad temp down on those long descents.

They bang on the spokes to warn you that the pads are worn down too much.

Little antennae to make it easier for the government to read your thoughts?