Hello, Calvin Jones here, Park Tool Company with Tech Tuesday.
today we want to look at the difference between the freewheel and the cassette.
You know, words do have power. In the bike industry, sometimes that means the power to confuse.
The two terms freewheel and cassette are not interchangeable -
we need to know the difference so we can get the correct tool for the job.
The older system is the freewheel system found on vintage bikes and less expensive bikes.
The freewheel itself is the cogs and the ratcheting clicking mechanism that lets us freewheel or coast
built into one unit.
The hub will have a large thread machined right into the hub
This is the older or less expensive freewheel system.
The cassette system also ratchets - it also lets us freewheel.
Outside the smallest cog will be a locking ring.
There are tool fittings inside that ring that look a little like a freewheel - but it's not.
The tool from Park Tool is the FR-5 that fits inside - we turn it counterclockwise
The ring comes off, the cassette stack comes off, and there are no moving parts in these cogs at all.
The clicking or ratcheting is here - built into this cylinder attached to the hub.
And now it's time for your test.
We have here a modern wheel - shiny cogs and lots of them. A disc. Off of a fairly new bike.
Let's have a closer look. Smallest cog we have a ring, there are tool fittings - but on the outside.
Look deep down inside, we see the fittings of a freewheel.
This is not a cassette hub, it is not a cassette stack.
Second question: a wheel. More shiny cogs. Let's have a look. Smallest cog: a ring. Hmm. Tool fittings inside.
This one is the cassette. This is a freehub system, using a cassette.
Why the change? Why now the modern freehubs over the freewheel style hubs?
Well, one reason is axle strength. It may be the same piece of metal,
but here the bearings are fairly close together.
That narrow spacing really gives the axle more leverage that can get bent easy and deform.
The cassettes: the bearings are spread apart wider so it's better leverage for the advantage of the hub. Stronger.
Having trouble visualizing this? Let's take an example and grab yourself a video guy.
So for the older system, the bearings are close together
so let's bring our feet - the bearing braces - close together.
We're going to put some stress on it and see how strong it is.
Easy to push over the video guy. Now let's go the freehub.
In the freehub systems, the cassette hubs: wider apart, we have braced.
we have moved our braces, our bearings out. Let's try it again.
Immobile. So get a video guy and try it. we'll see you next week