Another day of wheels (and so on).
A customer brought in a rear wheel built with a Corima "47mm" rim.
It's a carbon rim with 47mm rim height (WO versions exist too, but this one is tubular),
and "yonjūnana-miri" (literally "forty-seven mill") is the model name as-is.
FH-7801 24-hole, fully laser-welded 4-cross pattern.
I put a marker tape at the crossing point of the final cross on the non-drive side because
I wanted to capture the smoothness when squeezing it in your hand.
The center had drifted toward the drive side by about one sheet of paper,
but that's a normal amount of drift in that direction from long-term use, so no problem.
From here I could tension it more while maintaining center,
but not by much, so a rebuild was called for.
This freehub body is 10-speed only.
With a 9-speed sprocket, it won't pass beyond the spline tooth step (Shimano's usual practice),
and with an 11-speed sprocket, the spline depth is insufficient.
Since the customer said they wouldn't be upgrading to 11-speed for at least a while,
the rear hub was reused.
When I spun the hub axle by hand, the rotation was gritty, but
upon closer inspection, it wasn't the hub bearings but rather
the inside of the 6803-sized bearing on the outside of the freehub body had rusted.
By the time of the image above, I'd already replaced it with a new one of the same size,
but this freehub body has a bearing design that doesn't come apart easily.
I had quite a struggle with it.
Incidentally, this hand-built wheel's rear is quite smooth—
from when I started rebuilding it,
within less than ten minutes at the initial rough-build stage,
it had already reached the tension of the original finished state... but
The WH-9000-C50 tubular rear wheel that was also brought in for inspection
turned out to be even smoother.
In other words, a terrible wheel that undercuts even this smooth hand-built Corima.
No center offset, drive-side tension that didn't get worse when tightened further,
and no runout significant enough to require peeling off the tubular tire,
so I returned it to the customer as-is.
The fact that this is even smoother than the already-smooth Corima has a basis beyond mere feeling:
with the Shimano wheel, when standing and climbing, the spoke rubs readily,
whereas with the Corima, that doesn't happen.
Done.
Corima rims once had reverse drilled holes,
but by the original Medium generation they switched to forward drilling,
so naturally the wide-rim hand-build rims—32mm, 47mm, 58mm—
all have forward drilling.
Campagnolo and Fulcrum carbon rims are now forward-drilled too,
but that change is relatively recent.
FH-7801 24-hole, half-competition 4-6 cross pattern with tie-in.
A customer brought in a rear wheel built with a Corima "47mm" rim.
It's a carbon rim with 47mm rim height (WO versions exist too, but this one is tubular),
and "yonjūnana-miri" (literally "forty-seven mill") is the model name as-is.
FH-7801 24-hole, fully laser-welded 4-cross pattern.
I put a marker tape at the crossing point of the final cross on the non-drive side because
I wanted to capture the smoothness when squeezing it in your hand.
The center had drifted toward the drive side by about one sheet of paper,
but that's a normal amount of drift in that direction from long-term use, so no problem.
From here I could tension it more while maintaining center,
but not by much, so a rebuild was called for.
This freehub body is 10-speed only.
With a 9-speed sprocket, it won't pass beyond the spline tooth step (Shimano's usual practice),
and with an 11-speed sprocket, the spline depth is insufficient.
Since the customer said they wouldn't be upgrading to 11-speed for at least a while,
the rear hub was reused.
When I spun the hub axle by hand, the rotation was gritty, but
upon closer inspection, it wasn't the hub bearings but rather
the inside of the 6803-sized bearing on the outside of the freehub body had rusted.
By the time of the image above, I'd already replaced it with a new one of the same size,
but this freehub body has a bearing design that doesn't come apart easily.
I had quite a struggle with it.
Incidentally, this hand-built wheel's rear is quite smooth—
from when I started rebuilding it,
within less than ten minutes at the initial rough-build stage,
it had already reached the tension of the original finished state... but
The WH-9000-C50 tubular rear wheel that was also brought in for inspection
turned out to be even smoother.
In other words, a terrible wheel that undercuts even this smooth hand-built Corima.
No center offset, drive-side tension that didn't get worse when tightened further,
and no runout significant enough to require peeling off the tubular tire,
so I returned it to the customer as-is.
The fact that this is even smoother than the already-smooth Corima has a basis beyond mere feeling:
with the Shimano wheel, when standing and climbing, the spoke rubs readily,
whereas with the Corima, that doesn't happen.
Done.
Corima rims once had reverse drilled holes,
but by the original Medium generation they switched to forward drilling,
so naturally the wide-rim hand-build rims—32mm, 47mm, 58mm—
all have forward drilling.
Campagnolo and Fulcrum carbon rims are now forward-drilled too,
but that change is relatively recent.
FH-7801 24-hole, half-competition 4-6 cross pattern with tie-in.