A customer brought in a Bora One (high-performance carbon wheelset) for me to work on.
They wanted both wheels inspected,
but were particularly concerned about some radial runout in the rear wheel.
While not something you'd necessarily feel while riding,
when you look closely using the brake shoe as a reference point,
you can see the rim bouncing up and down.
Right below the G3 spoke and at the midpoint between spokes
I marked these spots with tape.
With the truing stand's gauge just barely touching at the midpoint,
I rotated the rim to the position directly below the G3 spoke
It looks like this...
It's hard to see, so I brightened the background,
but there's roughly this much inward deflection toward the inner edge.
With a 21-hole wheel, if this relationship is the same at all 7 midpoint phases
and all 7 positions directly below the G3 spokes,
then it's just a characteristic of G3 (three-cross) lacing and no problem.
The tire deformation at the contact patch is far greater anyway,
so you wouldn't notice anything when riding.
Actually, only the position directly below the G3 spoke where I'd placed the tape
was protruding further outward than the other 6 positions,
so at the time I took these photos, I tightened those 3 nipples
directly below the G3 to correct the radial runout.
I haven't touched any of the other 18 nipples
from the remaining 6 G3 positions
The rim was offset toward the anti-freewheel side.
This was the original condition.
I trued it and centered the wheel.
Next, the front wheel.
It was perfectly centered but had slight runout.
After truing, it remained perfectly centered, just as it was provisionally.
They wanted both wheels inspected,
but were particularly concerned about some radial runout in the rear wheel.
While not something you'd necessarily feel while riding,
when you look closely using the brake shoe as a reference point,
you can see the rim bouncing up and down.
Right below the G3 spoke and at the midpoint between spokes
I marked these spots with tape.
With the truing stand's gauge just barely touching at the midpoint,
I rotated the rim to the position directly below the G3 spoke
It looks like this...
It's hard to see, so I brightened the background,
but there's roughly this much inward deflection toward the inner edge.
With a 21-hole wheel, if this relationship is the same at all 7 midpoint phases
and all 7 positions directly below the G3 spokes,
then it's just a characteristic of G3 (three-cross) lacing and no problem.
The tire deformation at the contact patch is far greater anyway,
so you wouldn't notice anything when riding.
Actually, only the position directly below the G3 spoke where I'd placed the tape
was protruding further outward than the other 6 positions,
so at the time I took these photos, I tightened those 3 nipples
directly below the G3 to correct the radial runout.
I haven't touched any of the other 18 nipples
from the remaining 6 G3 positions
The rim was offset toward the anti-freewheel side.
This was the original condition.
I trued it and centered the wheel.
Next, the front wheel.
It was perfectly centered but had slight runout.
After truing, it remained perfectly centered, just as it was provisionally.