Originally Posted by
rseeker
Hey,
This is a question about the rim design on a bike I saw while looking. It's not about damage -- this is by design, on a brand new bike. The area where the caliper brake pads make contact on the rim has raised ridges and grooves, parallel to the circumference, all the way around.
Is this "a thing", done on purpose for good reason, or just some goofy manufacturer's design decision?
The ridges prevent brake squeal on test rides that might cause a potential buyer to purchase a different manufacturer's product.
Here's a Jobst Brandt (_The Bicycle Wheel_ author, mechanical engineer) quote stating that
http://www.sheldonbrown.com/brandt/machined-rims.html