Another wheel day (details omitted).
A customer dropped off a WH-R9270-C50-TL rear wheel.
They want me to do something about an annoying malfunction
with the Direct Engagement freewheel body that they can't stand.
There are two issues with the annoying malfunction.
First is the play between the freewheel body itself
and the hub axle.
When you squeeze both ends of the low gear
with your fingers from the state shown in the image and shake it,
there's enough play that it makes a clicking sound.
Later I removed the sprockets and grabbed the freewheel body itself
and did the same thing,
and sure enough there's play that you wouldn't see on a new one.
The clicking noise reproduces with 100% consistency
just from shaking it by hand,
so when actually pedaling, a crunching sensation
is transmitted through your feet, which is unpleasant.
The other issue is that the internal resistance
of the freewheel body is extremely high.
The FTS-L freewheel body from Mavic's Quick-release-era hubs
has the hub shell and freewheel body
connected gently via a rubber seal ring,
and when the resistance around the seal area
and the resistance around the pawls of the freewheel body
increase from dirt,
the rubber seal ring enters a half-clutch-like state,
causing the rotation of the hub shell (the wheel itself)
to be transmitted to the freewheel body.
As a result, when you lift the rear wheel off the ground,
manually spin the crank, and then let go,
the chain drive synchronized with the wheel continues for a while—
creating a "ghost pedaling" state.
In cases where the internal resistance of the freewheel body
is especially high, if you stop the spinning crank arm with your hand,
the crank stops but the freewheel body keeps spinning,
pushing the chain out onto the top of the chainstay,
creating slack. In severe cases the chain
actually contacts the top of the chainstay.
This freewheel body is experiencing
the exact same phenomenon.
When you lift the rear wheel and manually spin the crank,
ghost pedaling occurs. The ghost pedaling is
especially persistent in outer×top,
and in actual downhill riding when the chain is
around the outer×top range
and you stop pedaling, the chain gets pushed forward
and goes slack on top of the chainstay.
When you pedal again, there's a loss before the chain slack
snaps tight and transfers to wheel rotation,
plus an uncomfortable thrashing sensation as if it might drop the chain.
ZIPP once used something called the Cognition hub,
a proprietary freewheel design similar to this Direct Engagement
in the sense that it's neither 3–6 pawl pole springs
nor a cartridge ratchet—
adopting it on their flagship-grade wheels.
Weight-wise it's heavier than
the ZR1 hub that was used on mid-grade wheels,
but the Cognition hub's structure rather than weight
was supposed to be the selling point.
However, the Cognition hub also developed the defect
of becoming almost fixed-gear in operation when internals got dirty,
and now models that formerly used the Cognition hub
have been quietly switched to the ZR1SL,
a slightly lightened version of the ZR1.
They've now switched their messaging from the rear hub structure
to emphasizing lightness—"30g lighter than the previous model!"
Direct Engagement was originally first adopted
on the XTRA microspline rear hub,
and is currently used on XTRA and Deore XT hubs and complete wheels,
as well as Dura-Ace complete wheels.
The MTB side hasn't had huge numbers out in the world,
so I think the problem just isn't recognized as such.
The rear hub of the WH-R9270's successor model, the WH-R9370,
has the same structure, but if sales pick up going forward,
I suspect it will become much more apparent.
I'm hoping it doesn't turn into a situation like this issue
(→here)
where they tried to play dumb until September 2023.
The customer has contacted Shimano many, many times
through the shop where they bought the wheel,
but ultimately no solution has been reached.
They keep getting answers like
"This isn't a malfunction," "It's just how these are,"
but there's no way I can fix
a Shimano wheel defect that Shimano can't fix themselves.
I've written about it once before, but I haven't put everything out there—
I've seen many cases of the same symptoms with WH-R9270 freewheel bodies.
I told the customer, "I don't want to be wishy-washy, but
depending on the freewheel body's temperament,
sometimes it seems to just fix itself, right?" and they said that was exactly right.
Since they wanted a proper hub,
I swapped it out and rebuilt the wheel.
Revo Disc hub 24H black semi CX Sprint
46 reverse Italian lacing with inner spoke configuration.
When I checked with the centering gauge before disassembling the original wheel,
it was perfectly centered,
but the spoke tension on the freewheel side (multi-spoke side)
was a bit loose.
Whether it was that way from the start or became that way with use,
I can't say.
Now that the wheel has been disassembled,
there was obviously a moment when the rim was bare,
and naturally I did what needed to be done.
But I'm not telling you the results of that.
↑this guy's got some nerve lol
Slightly out of true, pardon the appearance!
Please take a look at this image!
↑Stop it right now!
A customer dropped off a WH-R9270-C50-TL rear wheel.
They want me to do something about an annoying malfunction
with the Direct Engagement freewheel body that they can't stand.
There are two issues with the annoying malfunction.
First is the play between the freewheel body itself
and the hub axle.
When you squeeze both ends of the low gear
with your fingers from the state shown in the image and shake it,
there's enough play that it makes a clicking sound.
Later I removed the sprockets and grabbed the freewheel body itself
and did the same thing,
and sure enough there's play that you wouldn't see on a new one.
The clicking noise reproduces with 100% consistency
just from shaking it by hand,
so when actually pedaling, a crunching sensation
is transmitted through your feet, which is unpleasant.
The other issue is that the internal resistance
of the freewheel body is extremely high.
The FTS-L freewheel body from Mavic's Quick-release-era hubs
has the hub shell and freewheel body
connected gently via a rubber seal ring,
and when the resistance around the seal area
and the resistance around the pawls of the freewheel body
increase from dirt,
the rubber seal ring enters a half-clutch-like state,
causing the rotation of the hub shell (the wheel itself)
to be transmitted to the freewheel body.
As a result, when you lift the rear wheel off the ground,
manually spin the crank, and then let go,
the chain drive synchronized with the wheel continues for a while—
creating a "ghost pedaling" state.
In cases where the internal resistance of the freewheel body
is especially high, if you stop the spinning crank arm with your hand,
the crank stops but the freewheel body keeps spinning,
pushing the chain out onto the top of the chainstay,
creating slack. In severe cases the chain
actually contacts the top of the chainstay.
This freewheel body is experiencing
the exact same phenomenon.
When you lift the rear wheel and manually spin the crank,
ghost pedaling occurs. The ghost pedaling is
especially persistent in outer×top,
and in actual downhill riding when the chain is
around the outer×top range
and you stop pedaling, the chain gets pushed forward
and goes slack on top of the chainstay.
When you pedal again, there's a loss before the chain slack
snaps tight and transfers to wheel rotation,
plus an uncomfortable thrashing sensation as if it might drop the chain.
ZIPP once used something called the Cognition hub,
a proprietary freewheel design similar to this Direct Engagement
in the sense that it's neither 3–6 pawl pole springs
nor a cartridge ratchet—
adopting it on their flagship-grade wheels.
Weight-wise it's heavier than
the ZR1 hub that was used on mid-grade wheels,
but the Cognition hub's structure rather than weight
was supposed to be the selling point.
However, the Cognition hub also developed the defect
of becoming almost fixed-gear in operation when internals got dirty,
and now models that formerly used the Cognition hub
have been quietly switched to the ZR1SL,
a slightly lightened version of the ZR1.
They've now switched their messaging from the rear hub structure
to emphasizing lightness—"30g lighter than the previous model!"
Direct Engagement was originally first adopted
on the XTRA microspline rear hub,
and is currently used on XTRA and Deore XT hubs and complete wheels,
as well as Dura-Ace complete wheels.
The MTB side hasn't had huge numbers out in the world,
so I think the problem just isn't recognized as such.
The rear hub of the WH-R9270's successor model, the WH-R9370,
has the same structure, but if sales pick up going forward,
I suspect it will become much more apparent.
I'm hoping it doesn't turn into a situation like this issue
(→here)
where they tried to play dumb until September 2023.
The customer has contacted Shimano many, many times
through the shop where they bought the wheel,
but ultimately no solution has been reached.
They keep getting answers like
"This isn't a malfunction," "It's just how these are,"
but there's no way I can fix
a Shimano wheel defect that Shimano can't fix themselves.
I've written about it once before, but I haven't put everything out there—
I've seen many cases of the same symptoms with WH-R9270 freewheel bodies.
I told the customer, "I don't want to be wishy-washy, but
depending on the freewheel body's temperament,
sometimes it seems to just fix itself, right?" and they said that was exactly right.
Since they wanted a proper hub,
I swapped it out and rebuilt the wheel.
Revo Disc hub 24H black semi CX Sprint
46 reverse Italian lacing with inner spoke configuration.
When I checked with the centering gauge before disassembling the original wheel,
it was perfectly centered,
but the spoke tension on the freewheel side (multi-spoke side)
was a bit loose.
Whether it was that way from the start or became that way with use,
I can't say.
Now that the wheel has been disassembled,
there was obviously a moment when the rim was bare,
and naturally I did what needed to be done.
But I'm not telling you the results of that.
↑this guy's got some nerve lol
Slightly out of true, pardon the appearance!
Please take a look at this image!
↑Stop it right now!