Bicycle Mechanics - I'm ignorant please explain freewheel vs cassette

Trust me, I searched the forum and read through some sheldonbrown but I simply don't get this.

so on nashbar, one rear wheel has the option of either being purchased as a freewheel or as a cassette.

I don't get it, doesnt the cassette go on the freewheel? Whats the difference between the two?

Please help a dummy like me.

Hello "steve"

Freewheel: back in the dark ages. Most multi-speed hubs used a freewheel. This type has the rachets built into the sprockets as one unit and screwed onto a hubs threads. This will later prove to be a poor design. For the spacing on the axle extend past the hub and have a greater chance of bending. As the Freewheels got more sprockets like an 8 speed, axles bent easier. Not to mention the bearings aren't placed evenly. Talking about the drive side. You also have to over dish the wheel compared to a freehub wheel.

Freehub: What if you redid the hub and moved the drive side bearings out further and shorted the axle spacing? Improve the rachets to be placed onto the hub in a body and separate from the sprockets. The hub body is bolted into the hub and would look like a naked freewheel without it's sprockets. Now the sprockets become what is know as the cassette. Which like a puzzle are notched and fit over the body that holds the rachets. The sprockets are keep on by a type of lockring.

so the freehub/cassette is just modern, better version?

"Correct"

They have just finished making 10speed cassettes. But they are running out of hub sizes before they start spreading the frames again...

great explanation pest...

now what to do with 14 speed by 2008...

allegedly..

great explanation pest...

now what to do with 14 speed by 2008...

allegedly..

Oh boy. :D

Nobody actually NEEDS that many speeds. Jesus.

And who needs the 3*10 currently available?

And who needs the 3*10 currently available?
Old codgers like me & loving it !!!

I'm currently ridiculously happy with 8 speed, and refuse anything more. No need. I do like all this 10 speed stuff, as now all the 8 speed components are getting less expensive.

By the by, great explanation on the differences there.

And who needs the 3*10 currently available?

I doubt anyone really needs it but, the nice part about the newer 9 and 10 speed cassettes is not really that you get any more range (it still starts at around 12t and ends at around 25t no matter what), but that you get more steps in between. It is nice to not have to ride a corn cob to get that feeling of finding just the right gear for the conditions. I have an old 12 speed, and the jumps with each shift are not at all subtle.

Pests explaination is great, but I'm even a tad overwhelmed by it. I think the original post needs a simpler version.

Freehub is the part on more modern bikes that ratchets and therefore allows you to pedal when you want and coast when you want.

Cassettes slide over the freehub, they are the actual gears with the teeth that the chain catches onto. So long as the freehub is long enough or you make some sort of sleeve that slides over the freehub, you can theoretically change your number of gears by just manufacturing different spacing between your cogs to make them closer or farther apart to squeeze in more or take out a few cogs.

FREEWHEEL: On older multi speed bikes the freehub and the cassette were inseperable, if you replaced one you replaced the other. I think the max # of gears i've ever seen on a freewheels was 5 different cogs. This is basically what BMX bikes have, but with only 1 gear back there.

Fixed Gear: the one gear is fixed to the hub, it will not allow you to coast, you cannot coast, you must always pedal your legs unless you're trying to stop the bike or it is already stopped. If the wheel is spining, so are your pedals. Advantage? forwards or backwards are both A-Okay.

Trust me, I searched the forum and read through some sheldonbrown but I simply don't get this.

so on nashbar, one rear wheel has the option of either being purchased as a freewheel or as a cassette.

I don't get it, doesnt the cassette go on the freewheel? Whats the difference between the two?

This is a Frequently Asked Question, so I made an illustrated Web page just about this distinction:

http://sheldonbrown.com/free-k7

By the way, in searching my Website, generally the best place to start is the Bicycle Glossary

http://sheldonbrown.com/glossary

Sheldon "It Matters" Brown

Did I read someplace that an advantage to casettes is that you only need to swap out a worn cog set, not both cogs and ratchet as in a freewheel?

Coyote--That's only true because cogs are more readily available now for freehubs than they are for freewheels. Both have cogs that are equally replaceable, and as easily replaceable, if you have the replacement cogs.

And FWIW Orange Leader, freewheels were made in up to *8* speeds.