Even though I didn't solve it, this story might help someone out there.
I received a rear wheel from an EA50 Aero from a customer.
They want to upgrade the freewheel body from Shimano 10-speed to 11-speed.
It has a clearly different freewheel body compared to
the R4 hub adopted in higher-end models.
I removed the freewheel body.
It has a 12mm diameter hub shaft with a shape that also serves as a bottom-out prevention spacer.
↑Here's the freewheel body.
Wait! I've seen this before!
My personal 10-speed cassette, the ultra-close-ratio fixed with a 7400 lockring
16–16–16–16–16–16–16–16–16–16T
(only the top gear is a dedicated 16T top sprocket), also known as
the "Death Beauty Facial Device," or as I call it, "Death Corn," which fixes
This freewheel body is exactly the same.
The depth to the bearing inside the freewheel body is identical,
and I've confirmed that the "Death Corn" even mounts normally on the EA50.
(The only difference is the color of the bearing seal)
As for where this came from—it's a 10-speed freewheel body that a customer gave me
when I was upgrading a Spinergy Zero Light's freewheel body to 11-speed.
The only difference between the Zero Light's 11-speed freewheel body and the 10-speed
is the amount of spline relief shaving, so
compatibility has been confirmed between
Zero Light 11-speed, Zero Light 10-speed, and EA50 10-speed.
I don't know if an 11-speed freewheel body for the EA50 is currently available,
but if upgrading with a Zero Light 11-speed,
the price is high enough to make me think "we really can't get that on this wheel,"
so we ended up shelving or putting it on hold this time.
Alternatively, if the EA50 freewheel body turned out to be available and cheaper than Spinergy,
then upgrading the Zero Light to 11-speed would be
Wait, who's that at this hour?
Whoa, what are you doing—stop!
I received a rear wheel from an EA50 Aero from a customer.
They want to upgrade the freewheel body from Shimano 10-speed to 11-speed.
It has a clearly different freewheel body compared to
the R4 hub adopted in higher-end models.
I removed the freewheel body.
It has a 12mm diameter hub shaft with a shape that also serves as a bottom-out prevention spacer.
↑Here's the freewheel body.
Wait! I've seen this before!
My personal 10-speed cassette, the ultra-close-ratio fixed with a 7400 lockring
16–16–16–16–16–16–16–16–16–16T
(only the top gear is a dedicated 16T top sprocket), also known as
the "Death Beauty Facial Device," or as I call it, "Death Corn," which fixes
This freewheel body is exactly the same.
The depth to the bearing inside the freewheel body is identical,
and I've confirmed that the "Death Corn" even mounts normally on the EA50.
(The only difference is the color of the bearing seal)
As for where this came from—it's a 10-speed freewheel body that a customer gave me
when I was upgrading a Spinergy Zero Light's freewheel body to 11-speed.
The only difference between the Zero Light's 11-speed freewheel body and the 10-speed
is the amount of spline relief shaving, so
compatibility has been confirmed between
Zero Light 11-speed, Zero Light 10-speed, and EA50 10-speed.
I don't know if an 11-speed freewheel body for the EA50 is currently available,
but if upgrading with a Zero Light 11-speed,
the price is high enough to make me think "we really can't get that on this wheel,"
so we ended up shelving or putting it on hold this time.
Alternatively, if the EA50 freewheel body turned out to be available and cheaper than Spinergy,
then upgrading the Zero Light to 11-speed would be
Wait, who's that at this hour?
Whoa, what are you doing—stop!