7bmwm3gtr

This is stupid to the ones who have been exposed to Cycling for quite a bit, but i really want to know this.

What is the roulette-like clicking noise in the rear wheel when a rider coasts? It's found in higher-end wheels and i wanna know if it's a bad thing or a good thing.

I personally like it, and if anyone has Bontrager Lites, (Not X Lite or anything higher) please tell me if they have this "noise"

Thanks, and sorry for the stupid question =p

silversx80

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

acaurora

I believe the term is "Freewheel", it is the device that allows your rear wheel to continue spinning despite you not pedaling. It is found on all road bikes (I think), and the only time you will not see it on a bike is on a fixed gear (unless they have it installed). The noise varies depending on the bike... I know that with my Allez it was very quiet but on my Tarmac it is definitely louder.

Fobdot

It's generally a bad thing. It's sound coming from the freewheel. Sound= energy = energy not used in spinning.
Although it's pretty insignificant. I had a wheelset that could wake the dead but they were high end wheels.
It's from the hub, not the wheel. It's nothing to worry about. To fix, just apply much grease.


NINJA EDIT: It's like a ratchet wrench. It clicks when it locks. That's the mechanism in the free wheel.

Cheers.

rollin

It's neither good nor bad. It's your bike's way of telling you to "Keep Pedaling Nancy!"

My bontrager race lites were silent.

If you want to hear loud wheels try to get near someone riding a Chris King rear hub, it's like being chased by a hive full of hornets!

It's not necessarily linked to higher end wheels.

umd

:facepalm:

Basil Moss

Thread fail. And as for this:

I'm not going to comment.

RacerOne

I suggest you disassemble it, that's the only way you'll know how it works. If you can get it back together that's a big bonus!

Braden1550

Gottaa pull mine apart anyway will post some pics for you in a sec so you understand.

EDIT:

Cleave

Hi 7bmwm3gtr,

As the saying goes, there's no such thing as stupid questions, but sometimes there are stupid answers.

The clicking noise is kind of hard to explain without photos, but fortunately Braden1550 supplied some interesting photos.

Anyway, in Braden1550's first photo, the three (3) object covered in grease that look like teeth are pawls. These are the things that cause the clicking noise. Braden1550's second photo shows the surface on the hub that the pawls engage. The pawls are spring loaded. When you stop pedaling the cassette is rotating in the opposite direction to the hub (relative to the hub) so the pawls click over the "teeth" in the hub. When you pedal, the pawls and the hub are moving in the relative same rotation and the springs are pushing the pawls so that they engage the teeth in hub.

A few corrections to some of the information above. All modern wheels have the pawl and engaging surface as part of the hub. So today the rear hub is sometimes referred to as a freehub. The gear assembly is called a cassette.

In the past, the pawls, etc. were part of the gear assembly and that was called a freewheel. The entire assembly screwed onto the hub.

There are a lot of advantages to the current design (freehub and cassette) and few disadvantages.

Finally, yes you can reduce the noise by putting more or heavier grease into the pawl assembly but don't. If you do the pawls may not engage the teeth properly and you can damage it to the point where they won't engaged at all.

Hope this helps.

Jynx

this thread has some of the dumbest answers i have ever read in my life along with some of the most helpful.

AndrewP

There are silent ones where the pawls are almost radial and the friction against a smooth surface is enough to lock them in position.

waterrockets 

***I'm thinking Braden may have just done this, but I can't see photobucket at work.***

Here's one opened up. You can see the ratchet bit on the end of the freehub body in his hand, and you can see the teeth inside the hub. The click occurs when the ratchets fall off one ramp and accelerate into the next one.

AngryScientist 

yes, the ratchets are called pawls. some wheels have more pawls around the circumference than others, and some use higher spring tension than others.as wr mentions the clicking is the snap return of the pawl. the viscosity of grease within the hub and spring tension (and number of pawls) determines the sound you will hear when coasting.

waterrockets 

Good call. I couldn't for the life of me think of the word "pawl." Man, I'm only 38 (this month). My memory recall is already getting a skip here and there.

Daytrip

Set it back down on the workbench and slowly step away from the grease, sir.

Grumpy McTrumpy

My name is Pawl. And this is between Y'all.

Psimet2001 

Grease.....:facepalm:

yes...use lots of heavy grease to silence it. Then be sure to take a video of you riding it once you get it all back together.

exRunner

No one actually explained why some are quite and some are noisy. Having not taken any of the "high end" freewheels apart, I have always assumed that the noisy ones are because their pawl springs are stronger and/or they have more pawls or deeper engagement teeth.

What's the real answer? I'm curious as well.

And to the guy that made the "noise = energy = bad" comment. Right concept, wrong application. Nice try, though. Save it for the next time you hear some one slapping their feet when they run and use.

Grumpy McTrumpy

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

Psimet2001 

the differences in sound come from different combinations of materials, spring tension, engagement points/pawl count, how the hub or wheel amplifys the sound or resonates....etc....a little bit of everything.

sd790

Waterrockets' freehub looks like it has two pawls. Here is a picture of a freehub with three pawls. This particular freehub was rather loud until I added some extra grease into these areas.

1223091442.jpg

Grumpy McTrumpy

The extra grease would probably soon be displaced by the pawls once you gave it a few revolutions. It would probably also act as an acoustic dampening material, like stuffing a helmholz resonator (or guitar box) with fiberglass insulation.

waterrockets 

Yeah, that's not my photo, but that one has three pawls on it. I'll bet a the same angle, yours looks like it only has two.

Psimet2001 

It is and it does, but it also has a nasty habit of making a little bit f vacum like suction not unlike getting your boot stuck in mud resulting in the pawls wanting to stick - loss of engagement.