Sounds From The Bike Hub & More Mysteries

Why does my bike hub make a sound?

The clicking/buzzing sound you hear when coasting is the freewheel's spring-loaded pawls moving over the ratchet teeth, which are moving in relation to the fixed position pawls. 



The sound differs depending on the brand and make of your wheel hub. The type of noise and how loud it is when you're coasting on your bike is entirely up to personal preference, as it does not really impact your ride at all. 
 

Do more expensive hubs make a louder sound? 

The noise they make depends on the design of the hub. Price is not related to noise produced, though many high-end wheels do tend to be noisy due to a higher pawl/ratchet count, and manufacturing with quality materials and tight tolerances. An excessively loud noise from the wheel hub has become an unofficial mark of quality, but it doesn't make you a better cyclist, maybe just a little more noticeable. 

Does the generation of this sound waste energy?

I've never heard makers of more quiet freewheels claim their designs waste less energy. I admit that I don't fully understand how the physics would work here, but my educated guess is that the less fewer pawls and less friction involved, the slower and less secure the engagement of the chain and gear would be.

While some riders may prefer a quiet ride, they all want their freewheel to engage quickly and securely.
 

What if I don't like that annoying buzz?

For those that like the quiet ride, famously silent freewheels include American Classic, which uses a 6-point pawl and cam plate design, and Shimano, which are specifically engineered to be quiet.

Many riders, myself included, enjoy the buzz of a moderately loud freewheel.
 

What if I want an extra loud motivational freewheel? 

Hubs known for loud volume include Chris King, Hope Pro, DT Swiss, and Hugi, which used an 18 pawl "star ratchet" design.

Some racers prefer a quiet hub, as it doesn't let riders near them know when they're coasting or drafting.