Hey folks!
In the video talking about the XTR 12 speed mech,
I mentioned that disk seems to be bent and twisted,
definitely compared to a SRAM Eagle 12 speed alternative,
so why don't we take a closer look and see what that is about.
In that video I showed you how the cage is bent,
definitely visible with the naked eye.
And also how the top and the bottom jockey wheels don't seem to line up with each other,
giving you the twisted look of that same derailleur cage.
However, after playing a little bit with this Shimano 12 speed
and having the experience of the SRAM Eagle 12 speed on my bikes,
I think the Shimano XTR 12 speed it's a bit more of a refined design.
It sounds like it's not a new design
because it's something that they've used in the past for road
on the 11 speed drivetrains, and this is what I mean.
One of the challenges of the 1x drivetrains is definitely the chainline,
something that in the past we would call the cross-chaining,
now it's considered to be acceptable.
Yes, the new chains or a lot better for allowing you to do that.
However, the extreme of the cassette, so the biggest cog and the smallest cog,
definitely put a lot of stress on the components,
and more specifically the derailleur cage, and that bottom jockey wheel.
So let's take the two extremes:
First, with the chain on the smallest cog,
your derailleur cage it's almost parallel to the ground,
almost horizontal, and yes,
Shimano added this little bumper here just so the chain doesn't rattle onto the cage.
How does the bend or twist help in this case?
Looking at the chainline from the top of the cassette,
you can see how it goes far left towards the chainring.
Looking down that derailleur,
this is the bent, like this.
And the twist of the bottom jockey it's like that, relative to the top jockey wheel.
And in this bottom view you can see the chain line
and you can understand hopefully how having the cage bent like that,
actually helps the bottom jockey being lined up better
with the chain, at that extreme angle.
So with the chain on the smallest cog,
the bend in the cage seems to help,
I don't think the twist in the cage does a whole lot in this case.
And that brings us to the other extreme:
chain on the largest cog,
which causes the derailleur to be almost vertical,
And this bottom jockey now it's gonna be a bit bent like this,
so the bottom is further away from the spokes.
Also, the tip of it here is angled a little bit towards the chain ring,
and that should help at this extreme of the cassette.
And this is how extreme that chain line looks like from the top.
This is an 11-50 cassette.
And from the bottom you can see how that bottom jockey is angled perfectly
towards the chain ring so
I believe that all the changes to the cage here
were made specifically for this scenario,
chain on the largest cog
which gives you the most extreme chain line of this drivetrain.
On an Eagle drivetrain, you have the same extreme chain lines,
and you don't have the cage here, bent or twisted.
However, if you look at this bottom jockey
it does use narrow wide profile teeth
which I assume help guide that chain properly on its way to the cassette.
So there you have it guys!
Clever design from Shimano.
Definitely, if you get a derailleur with that bent and twisted cage,
don't bend it back!
Because this might help your chain, chain line, and that bottom jockey in the long term.
And that's the end of my video as well.
Hope you guys found is useful.
If you have any questions, as usual, let me know in the comments below.
Don't forget to Like and Subscribe,
and until next time,
I will see you guys on the trails.
Cheers guys,
Cheers!