A customer brought in the front wheel of a Shimano WH-RX05 for servicing.
When applying the front brake, the front wheel tilts and shifts toward the left side (rotor side),
so I took it for a test ride myself
and wow that was scary — the hub felt pinched and twisted,
and there was a subtle steering pull to the left with a jarring sensation.
There's no play in the headset (the feeling is similar),
and since this doesn't happen with other front wheels including the ones on my own Iron Cross build that I assembled,
it seems the problem is isolated to just this wheel.
The front quick-release wasn't loose either.
The hub bearing adjustment wasn't slack.
Black aero spokes with spoke weight ratio around 100%,
in a 28-hole four-cross pattern,
but the spoke tension was clearly sagging,
so I did a significant retensioning job including centering correction.
After that, I had the customer take it for another test ride,
and they said the distorted feeling was completely gone even under hard braking,
so maybe the spoke tension was the only culprit.
I haven't encountered another case this severe, so I can't say for certain.
On a different note, the customer with this wheel
apparently owns a complete R9100 wheelset (C60 tubular).
I might finally get to handle the real thing.
There are some puzzling quirks with the new R9100 wheelsets, and
first I lined up the tubular spec sheet values for the R9100 alongside the previous 9100 model.
The R9100 has gone along with the times by adopting a wider rim.
Though "wider rim" varies in how much wider it actually is,
a 28mm width is quite broad by any standard.
I said "gone along with the times" because I can't say outright that "wider rims = rim evolution,"
so I was being intentionally ambiguous—
it's not a criticism of Shimano wheels. I'll get to other criticisms later.
Only the C40's rim height doesn't match its name at 37mm high,
but I shouldn't make a fuss over such a detail.
Next, looking at the clincher spec sheet values, and get this:
the C40 and C60 rim dimensions are exactly the same as the previous C35 and C50 specs.
Many people don't know about this or haven't noticed,
and even the customer with this wheel didn't realize that their C60 clincher has a 50mm rim height
(even though they own it).
When I looked into it, I found many industry colleagues writing things like
"the 40mm rim height is just right" or "the rim height became 40mm"
about the C40 clincher,
so it seems plenty of people—both sellers and buyers—are being fooled.
Since the rim dimensions are identical, I thought I could compare wheel weights,
so I added catalog weights for the clincher versions as well.
And here's what's puzzling: the weight difference between the 9100's C35 and the R9100's C40 is
8g for both front and rear (with the R9100 being heavier),
but when you get to the C50 and C60, the front is 80g heavier
and the rear is 99g heavier (again with the R9100 being heavier).
Looking at the front wheel, the front hub looks identical (aside from color),
so it's hard to imagine it generating such a large weight difference.
The spoke gauge had more detailed specs on the 9100, but
the R9100 only mentions they're aero-butted,
and even if we assume the 9100 is equivalent to CX-RAY (about 65% weight)
and the R9100 is equivalent to CX (about 100% weight), you still wouldn't get an 80g difference.
So my current assessment is:
the C35 and C40 rims are the same (aside from color),
and for C50 and C60,there's something they're not proud of, so
they've made heavier rims but kept the dimensions the same.
I've thought about buying just the R9100 C60 clincher rear wheel
and taking it apart to inspect,
but it's so damn expensive (←that's not a comment on rim height, just to be clear)
that I can't justify it.
The list price is ¥112,084 before tax. Yikes.
Actually, the price isn't particularly higher than the 9100 C50,
so that's interesting.
I thought, "I guess I'll just have to wait for a customer to bring in a broken rear wheel,"
but since I don't even see any unbroken rear wheels around,
that day might never come.
When applying the front brake, the front wheel tilts and shifts toward the left side (rotor side),
so I took it for a test ride myself
and wow that was scary — the hub felt pinched and twisted,
and there was a subtle steering pull to the left with a jarring sensation.
There's no play in the headset (the feeling is similar),
and since this doesn't happen with other front wheels including the ones on my own Iron Cross build that I assembled,
it seems the problem is isolated to just this wheel.
The front quick-release wasn't loose either.
The hub bearing adjustment wasn't slack.
Black aero spokes with spoke weight ratio around 100%,
in a 28-hole four-cross pattern,
but the spoke tension was clearly sagging,
so I did a significant retensioning job including centering correction.
After that, I had the customer take it for another test ride,
and they said the distorted feeling was completely gone even under hard braking,
so maybe the spoke tension was the only culprit.
I haven't encountered another case this severe, so I can't say for certain.
On a different note, the customer with this wheel
apparently owns a complete R9100 wheelset (C60 tubular).
I might finally get to handle the real thing.
There are some puzzling quirks with the new R9100 wheelsets, and
first I lined up the tubular spec sheet values for the R9100 alongside the previous 9100 model.
The R9100 has gone along with the times by adopting a wider rim.
Though "wider rim" varies in how much wider it actually is,
a 28mm width is quite broad by any standard.
I said "gone along with the times" because I can't say outright that "wider rims = rim evolution,"
so I was being intentionally ambiguous—
it's not a criticism of Shimano wheels. I'll get to other criticisms later.
Only the C40's rim height doesn't match its name at 37mm high,
but I shouldn't make a fuss over such a detail.
Next, looking at the clincher spec sheet values, and get this:
the C40 and C60 rim dimensions are exactly the same as the previous C35 and C50 specs.
Many people don't know about this or haven't noticed,
and even the customer with this wheel didn't realize that their C60 clincher has a 50mm rim height
(even though they own it).
When I looked into it, I found many industry colleagues writing things like
"the 40mm rim height is just right" or "the rim height became 40mm"
about the C40 clincher,
so it seems plenty of people—both sellers and buyers—are being fooled.
Since the rim dimensions are identical, I thought I could compare wheel weights,
so I added catalog weights for the clincher versions as well.
And here's what's puzzling: the weight difference between the 9100's C35 and the R9100's C40 is
8g for both front and rear (with the R9100 being heavier),
but when you get to the C50 and C60, the front is 80g heavier
and the rear is 99g heavier (again with the R9100 being heavier).
Looking at the front wheel, the front hub looks identical (aside from color),
so it's hard to imagine it generating such a large weight difference.
The spoke gauge had more detailed specs on the 9100, but
the R9100 only mentions they're aero-butted,
and even if we assume the 9100 is equivalent to CX-RAY (about 65% weight)
and the R9100 is equivalent to CX (about 100% weight), you still wouldn't get an 80g difference.
So my current assessment is:
the C35 and C40 rims are the same (aside from color),
and for C50 and C60,
they've made heavier rims but kept the dimensions the same.
I've thought about buying just the R9100 C60 clincher rear wheel
and taking it apart to inspect,
but it's so damn expensive (←that's not a comment on rim height, just to be clear)
that I can't justify it.
The list price is ¥112,084 before tax. Yikes.
Actually, the price isn't particularly higher than the 9100 C50,
so that's interesting.
I thought, "I guess I'll just have to wait for a customer to bring in a broken rear wheel,"
but since I don't even see any unbroken rear wheels around,
that day might never come.