Why do some rear wheel hubs make a louder noise than others?
 

Is there a functional reason for it?
Is it simply designed in by the makers?
Is there a way of making the noise quieter/louder?
Any thoughts gratefully received.

Basically, the way the pawls/ratchets in there were designed. Check out the GCN video for a good explanation.

It's simply a characteristic of hubs, with no rhyme or reason to it - some are simply louder than others. Campagnolo hubs were traditionally pretty loud, Shimano are traditionally very quiet (although my current Campag Zonda hub is ghostlike compared to my previous Rolfs, which used a DT hub). A guy I ride with - I think he has a Specialized bike, but I have no idea what hubs - his rear hub sounds like the proverbial swarm of angry hornets doused in meth. Loudest bloody hub I ever heard. If your hub is too loud, you might try adding more or thicker grease, but don't overdo it, as you might end up interfering with pawl action.

I'm curious about this as well. In my area, it seems people with high end, newer road bikes always have the loudest hubs.

If a hub is loud, does that not make it generally less efficient than a quieter hub as well?

I used to dislike my bikes/wheels with the louder hubs. But, I now view louder hubs as a "safety feature"!
When I am approaching pedestrians, and other cyclists, if I pause my peddling, the hub noise alerts the pedestrians & cyclist that someone is approaching.
Try it, I think you will find it is quite effective, at least in my experience it is, they will turn and look, but it doesn't seem to startle them, works especially on MUPs and other locations when the ambient noise is not too high.

I have Campy Protons and Zondas and they are very audible but I do notice people turn their heads when I approach on the loop in Central Park. For me it is a good thing.

My Shimano hubs are almost dead silent, like being a ninja on a bike. My Sun Ringle hubs are obnoxiously loud. My SRAM hubs fall somewhere between the Shimano and Sun Ringle.

I have older wheels with quiet freewheels and freehubs. In the short run, louder hubs would annoy me greatly, but I take the point about the safety feature.

Otto

The reason for loud hubs? Advertising. The quiet hubs never get noticed.

As a racer back in a distant millennia, I use to grease my SunTour freewheels because I never wanted to advertise that I was doing less work than those around me.

That's actually a really good case for having a loud hub that I hadn't thought of.

I've considered taping a piece of plastic to my seat stay in the path of the spokes to make my bike sound like a "motorcycle" (like I did when I was a kid).

Ringing my bell doesn't work well because 50% of the time the people are startled and jump into my path, and 25% of the time people are annoyed by me ringing my bell "at" them.

What's a SunTour? Is that one of those long rides you take when it is sunny.

I sometimes like the noisy freehub and sometimes I don't as much. My touring bike is by far the loudest with an Industry Nine freehub on Paul hubs and it is always funny when people ask if it is broken.

The loud hub fans are just like the loud pipe motorcycle fans.

Put a fairly loud hub in one of those hollow carbon fiber disc time trial wheels and you will scare away animals.



freewheeling in my Rohloff is quiet





..

I used to love my dead-silent Shimano hubs back when I was road racing...I could sometimes sneak up behind someone and draft for quite a while without being noticed.

My rear end makes exceptionally loud noises. It’s a point of pride, if I do say so.

You could probably put weaker return springs in the pawls of a noisy drive unit, but why???

There's a variety without ratchet pawls, probably moist commonly found in single-speed coaster-brake bikes, but not always. I once had a Raleigh Technium touring bike with that. One day I was out riding with a friend and all at once he said, "Hey, your bike don't make no noise." I like things quiet.

https://en.wikipedia.org/wiki/Freewheel

+1 Why give that away! Making a really good and silent freewheel mechanism isn't hard. The new noisy ones aren't better, just a whole lot louder. Racing is a chess game as much as it is a test of strength. Why start the game without your knights?

In short no. But usually over time the pawls wear the edges down and become a little quieter. There are designs in which the clearance between the pawl and the hub is very narrow and the angle of the hub locks so sharp that the hub is so quiet it is effectively soundless. I really like these but the Chinese hubs most commonly available these days for a reasonable price are so loud that freewheeling a quarter mile aware from some jogger on a path makes them leap off as if they're about to be run over.

Got new wheels recently and the new rear hub is very loud compared to the old one. Was very annoying, almost sounded like a deisel truck behind me whenever i'd start coasting. Thankfully it's getting quieter with use. After 400 miles or so, it is still a bit loud but not nearly as loud as it was. So maybe they get quieter after break- in period.

:)

Quality
 

I do like the silent hubs better; but my loud hubs have quicker engagement, which I really like. I'd like to think that the extra noise was from the extra pawls or similar, as opposed to marketing driven sound engineering, but I am probably fooling myself.

I also disliked loud hubs but after doing group rides, I actually started liking them. Louder hubs make a great warning system when someone in the group breaks cadence.

Sorry, but if I had to listen to that stupid buzz the whole time during a long ride, I'd want to kill someone.

It's really got a "fingernails on chalkboard" effect on me for some reason.