A customer brought in the front and rear wheels of a Dura-Ace C36 for inspection.
They requested a checkup.
Let's start with the rear wheel.
As expected of a Shimano wheel—
the kind that makes you proud to own it—
the spokes are showing signs of age.
There are areas where the paint is flaking off like eggshell,
and rust is surfacing on both sides indiscriminately.
Since it's not just dirt, wiping it off won't make it clean again.
I wrote "age-related" changes earlier,
but regardless of when it was purchased,
the manufacturing date was May 2022.
The provisional centering was spot-on.
There was some runout, so if I searched,
there's likely a phase shift of about one or two sheets of paper somewhere.
For just over a year of actual use since hanging on the shelf,
it's within the realm of possibility,
but the spoke tension had sagged, so
I focused on tightening the freewheel side
while also truing, and tensioned the wheel.
At this point, the rim is shifted toward the freewheel side.
From that state, I then tightened the non-freewheel side
to bring it into center.
Next up, the front wheel.
Manufactured in October 2021,
so it's slightly different from the rear wheel's date,
but this was during the period of extreme component and wheel shortages from Shimano,
so it may have taken time to get matching front and rear wheels.
It was hard to confirm, so I didn't check,
but for a 2021 unit,
there's a high likelihood of finding a MAC spoke stamp on the spoke head
(→here).
In fact, the front wheel rebuilt at that link was also TJ.
Though it was C50, not C36.
It's far from stainless, so the tensile strength is probably high,
but Sapim and DT spokes don't surface rust like this.
Sapim and DT have slightly different spoke construction,
so it's certain they don't have the same manufacturer,
but the spoke weight ratio matches one other company
(hard to see this as coincidence).
Strictly speaking, what's being matched isn't the spoke weight ratio
but the dimensions of the butted section.
I think DT was first with round-butted and the flat spokes requiring slit flanges,
but Sapim beat them to aero spokes that fit round holes.
For R9200-series Dura-Ace wheels,
they're assembled with spokes lighter than the 65% spoke weight of CX-RAY or Aero Lite,
and whether they chose a manufacturer that's easier to order custom spokes from
or went with a spoke manufacturer that complete wheel builders normally wouldn't pick for cost reasons—that's unclear.
The front wheel's provisional centering was also spot-on,
and since the spoke tension was actually on the tight side,
I just corrected about three minor runout points.
After the work, it was dead-centered,
but I forgot to take photos of either wheel.
Also, there's a 140mm disc rotor with some major runout on one spot that they also left with me.
When I installed it on the rear wheel of my personal bike,
the one spot with major runout and
two spots with slight pad contact
I corrected with the proper tool,
and now with my SRAM brake caliper at least,
it's straight enough that there's no contact under unloaded rotation.
I have photos of that, but I'm not posting them here.
I've printed them and given them to the customer.
They requested a checkup.
Let's start with the rear wheel.
As expected of a Shimano wheel—
the kind that makes you proud to own it—
the spokes are showing signs of age.
There are areas where the paint is flaking off like eggshell,
and rust is surfacing on both sides indiscriminately.
Since it's not just dirt, wiping it off won't make it clean again.
I wrote "age-related" changes earlier,
but regardless of when it was purchased,
the manufacturing date was May 2022.
The provisional centering was spot-on.
There was some runout, so if I searched,
there's likely a phase shift of about one or two sheets of paper somewhere.
For just over a year of actual use since hanging on the shelf,
it's within the realm of possibility,
but the spoke tension had sagged, so
I focused on tightening the freewheel side
while also truing, and tensioned the wheel.
At this point, the rim is shifted toward the freewheel side.
From that state, I then tightened the non-freewheel side
to bring it into center.
Next up, the front wheel.
Manufactured in October 2021,
so it's slightly different from the rear wheel's date,
but this was during the period of extreme component and wheel shortages from Shimano,
so it may have taken time to get matching front and rear wheels.
It was hard to confirm, so I didn't check,
but for a 2021 unit,
there's a high likelihood of finding a MAC spoke stamp on the spoke head
(→here).
In fact, the front wheel rebuilt at that link was also TJ.
Though it was C50, not C36.
It's far from stainless, so the tensile strength is probably high,
but Sapim and DT spokes don't surface rust like this.
Sapim and DT have slightly different spoke construction,
so it's certain they don't have the same manufacturer,
but the spoke weight ratio matches one other company
(hard to see this as coincidence).
Strictly speaking, what's being matched isn't the spoke weight ratio
but the dimensions of the butted section.
I think DT was first with round-butted and the flat spokes requiring slit flanges,
but Sapim beat them to aero spokes that fit round holes.
For R9200-series Dura-Ace wheels,
they're assembled with spokes lighter than the 65% spoke weight of CX-RAY or Aero Lite,
and whether they chose a manufacturer that's easier to order custom spokes from
or went with a spoke manufacturer that complete wheel builders normally wouldn't pick for cost reasons—that's unclear.
The front wheel's provisional centering was also spot-on,
and since the spoke tension was actually on the tight side,
I just corrected about three minor runout points.
After the work, it was dead-centered,
but I forgot to take photos of either wheel.
Also, there's a 140mm disc rotor with some major runout on one spot that they also left with me.
When I installed it on the rear wheel of my personal bike,
the one spot with major runout and
two spots with slight pad contact
I corrected with the proper tool,
and now with my SRAM brake caliper at least,
it's straight enough that there's no contact under unloaded rotation.
I have photos of that, but I'm not posting them here.
I've printed them and given them to the customer.