FreeWheel vs Cassette

[Tyran]

I've read up on the Freewheel but keep hearing or seeing it in contrast to the cassette and am a bit confused by that. Isn't a freewheel simply a device in the hub or attached to the hub; on which a cassette is placed, and allows it to spin freely when the biker is coasting or not using the pedals?

[mfried]

You could probably consult John Richards.

"The 2001 Ig Nobel Prize Winners were honored in a gala ceremony at
Harvard on October 4. Seven of the ten attended the ceremony, and two others sent taped acceptance speeches. The prizes were physically handed to the winners by four Nobel Laureates....

LITERATURE John Richards of Boston, England, founder of The Apostrophe
Protection Society, for his efforts to protect, promote, and defend the differences between plural and possessive"

[sjannasch]

The freewheel does have bearings, otherwise it couldn't coast. These bearings, however are separate from the bearings that hold the bicycle up, and they only turn when coasting.

You're quite welcome...but please seek professional help for your apostrophe abuse poblem... ;-)

Sheldon "Ellipsis Abuser...No Help For Me...Incurable..." Brown
+-----------------------------------------+
+-----------------------------------------+ Harris Cyclery, West Newton, Massachusetts Phone 617-244-9772 FAX 617-244-1041 http://harriscyclery.com Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

[MrWiZo]

That's possible too. However, did I also have it right?

I'd really hate to think I'm riding around confused... <G>

[Tyran]

Thanks fellows. I now see where I was confused.

To dumb it up, a 'freewheel' is a separate piece with cogs, that screws on to the hub; but has no bearings, and is not part of the axle support structure, etc. Is older style, etc.

Whereas a 'cassette' or 'freehub' has an integated ratchet in the hub, on which cogs can be mounted. The bearings are on the 'end' of this, making it stronger and part of the axle support system. Shimano started this 'new' style.

I was just thinking of these as 'old style' and 'new style' freewheels' and
I was thinking of a 'cassette' as just a set of cogs.

Thanks for the 'article' and the clarification in your comments.

[sjannasch]

Not in standard bicycle terminology. This is a common cause of confusion, so I've put up a special Web page about exactly this issue:

http://sheldonbrown.com/free-k7.html

Sheldon "Never The Twain Shall Meet" Brown
+----------------------------------------------------------+
+----------------------------------------------------------+ Harris Cyclery, West Newton, Massachusetts Phone 617-244-9772 FAX 617-244-1041 http://harriscyclery.com Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

[MrWiZo]

I think you're still confused, but I could be wrong.
Even in the face of my possible wrong-ness, I'll say what I think, and be corrected (and so learn).

Wrong. A freewheel has the cogs, and screws on to the hub, and has the ratchet mechanism; and (I'm not so clear on this part) supports the rider's weight too, rather than the axle going through it to the frame's dropout.

Mostly wrong. A freehub is the hub of the wheel, and has the ratchet mechanism inside it. A cassette is the collection of cogs that slides onto the freehub.
The freehub axle goes all the way through to the dropout.

It's confusing. Just look at it this way:
Freewheel: Cogs and ratchet mechanism all in one.
-Apparently prone to axle breakage
Cassette: Cogs for use on a freehub.
Freehub: Ratchet mechanism inside hub for use with cassette.

I do know that much from experience; I have a few cassettes that have been replaced on my MTB and one from my road bike, and they are definately just a bunch of cogs fastened together.

I also have a freewheel that broke from another bike, and it has the ratchet mechanism inside it, and screws on to the hub. It broke in so far as the ratchet mechanism failed. I do remember the axle did go right through it to the dropout, so no explanation as to why I seem to have read

something.

[Bluecynic]

Not exactly. Well, yes, sort of. A freewheel is a device that allows the wheel to spin freely in one direction (forward) when the rider is not pedalling. But the sprockets are not called a cassette in general.

The old style is to have a freewheel on which are installed several sprockets. The freewheel is then threaded onto the hub. A "cassette" wheel is slightly different. The "freewheel" part -- called a freehub in this case -- is an integral part of the hub itself, still serving the same function as a freewheel. The structural difference is that it is not simply threaded onto the hub, but is a part of the hub design. The cassette is then the bare sprockets, which usually fit onto a splined portion of the freehub.

The operational difference is that a freewheel system forces the bearing to be inside of the last sprocket (almost)-- a long, unsupported distance from the frame. This gives considerable leverage from the frame (where the rider weight goes) to the bearing (which takes that force), with only a skinny axle to hold you up. It breaks often. A cassette style hub has bearings closer to the frame, so there is not so much unsupported axle length, and not the leverage that can break axles.

Also, in theory a cassette hub allows you to replace worn sprockets easier. In practice, though, most people just replace all the sprockets at once. But at least you don't have to replace the freewheeling mechanism just because the sprockets are worn out.

[jezmond]

Er, you type with your hands, don't you? Isn't that enough?

You can't put scare quotes around words on the phone either. How DO you cope???