Hello, Calvin Jones here for Park Tool Company.
In this Calvin's Corner video
we're going to focus on the narrow wide chainrings
these are becoming quite popular and trendy on mountain bikes
and cyclocross bikes.
The wide narrow chainrings are well named.
Let's look at this picture and see that there is a narrow
and a wide then narrow and a wide tooth on the left.
These match up with the chain on the right.
You'll see that the two outer plates are matching with the wide tooth the two
inner plates with the narrow tooth. It seems to be that wide tooth
that locks and holds the chain as it comes around.
So this chain ring is used
only when there is a single front chainring, no front derailleur is used.
It is best used with the clutch style rear derailleurs.
So let's get a better idea by some testing
of how they work and when they work.
Here we're gonna do a test, we're going to apply a
bouncy load to the chain, slapping back and forth
in that horrible load, the lateral side load.
In a regular chainring with no guide
it just seems to fall off very easily. This is why you would never want to run
a normal chainring without a front derailleur or a protection of some type.
Now let's put on a narrow wide chainring
and let's run that same type of test again.
So a bouncy situation
impacting the chains, slapping around going sideways.
It really does tend to stay on pretty well.
So on good circumstances these chainrings do seem to do their job.
However, there are circumstances that this chainring
will still fail. These are when it's very rough conditions
- that's cyclocross and mountain biking -
but combined with mud.
So let's see a recent case where something occurred
like a failure. Keep an eye on our rider
as he transitions from dirt to payment and watch the bounce of the chain.
It dropped. Right there is the chain slap, it falls off,
we can see him at the top of the screen now
get off his bike, he is going to fix that, he is going to get back on
and get going.
When can this happen?
again, rough and bouncy conditions combined with mud.
But the worst constituent of mud is actually clay.
I don't know if this was the case in the Czech Republic,
but clay build-up tends to fill up the teeth
it raises the rollers. Let's have a look what happens with a chain ring that is
with this clay
Here we're applying the same type of load and we do get a failure.
Nothing different than we did before, but it does fail.
A sideways view gives us
the best action of what's really going on.
Normally at the 12 o'clock position we would see that chain
locked in place, but the mud is filling up
between the pointed teeth lifting that roller
and we can see some daylight there where it should be locked down.
What happens? We get just the right bounce
at just the wrong time and over
it can go.
So what would be best then? A guide
in addition to these special chainrings. This is much like a derailleur
it wraps around the chain and holds it in
So you might ask yourself: why should I bother with the special rings?
Why not just run a traditional chainring
run a chain guide, that's probably gonna save some money.
Let's see what happens. Here we have the chain guide
with traditional chainring. It does a better job, but it does come off
a complete failure. It's better than nothing,
but still you can't call it the best.
So if you want the most security,
we really need to run a guide of some sort
and a special designed ring that can be good holding power.
Here, it's not coming off.
So in conclusion again, if you want the most secure,
run with the guide and the narrow wide,
suspenders and a belt. Thank you.