A customer brought in a
Bontrager Aeolos 3 tubular rim front wheel
for repair.
A straight spoke had broken at the head.
The original spokes were DT Aerolite,
so I'll replace the broken one with a Sapim CX-RAY straight spoke
that has the same butted section dimensions and spoke density.
When I pulled out the nipple from the side
where the spoke had broken,
the fractured spoke head
was still stuck inside.
↑That piece
I recovered the broken spoke.
If this nipple were to drop inside the rim,
I'd have to remove the tubular tire,
which would multiply the work required.
This nipple has a 3.2mm square grip on the outer side as well,
which is normally how you'd adjust tension,
but since the customer wanted to avoid removing the tubular tire,
I'm using the inner grip.
If this were a nipple from one of those Reynolds wheels from a certain period,
the inner grip would be short and the corners oddly rounded,
making it impossible to turn once the wheel is built up under tension.
It would definitely strip.
Those are decorative, or meant only for pre-assembly.
After replacing the spoke and truing the wheel for lateral run-out,
there was a slight centering issue, which I corrected.
I'm using a Park Tool WAG-4 centering gauge
(WAG is an acronym for Wheel Alignment Gauge)
rather than my usual Hozan,
because it can measure even when the tire
overhangs the rim,
in other words, you can measure with the tire on.
However, this WAG-4 can't detect gaps
that Hozan would call a one-sheet-of-paper center offset,
so its accuracy is inferior, which is why
I don't usually use it.
It's fixed.
I asked the customer why they brought it here
instead of to the nearby Trek shop,
and they said they didn't think it could be fixed on the spot
and they don't trust their technical ability.
The tire appeared to be glued on with rim cement,
and when I asked the customer, that was indeed the case (not tape).
The valve is at an angle because
the cement melted slightly from brake heat on the descent,
causing the tire to shift relative to the rim.
When this happens, the direction the tire leans
is toward you when the valve is at the top,
so the image above shows the right side of the rim.
When I asked where the customer lives,
they said they're near Mount Rokko, so I explained that
if they reverse the wheel at the summit and descend moderately,
it might correct itself,
but it could also go the other way and lean backwards.
↑The broken Aerolite and the replacement CX-RAY
↑Spoke head side
The replacement CX-RAY
is a threadless 310mm spoke
with an extended plain section
that accommodates lengths up to 270mm,
and luckily,
the boundary between the butted section on the rim side
matches the original spoke almost exactly,
so even looking at the wheel afterwards,
you can't tell it's a replacement spoke.
Bontrager Aeolos 3 tubular rim front wheel
for repair.
A straight spoke had broken at the head.
The original spokes were DT Aerolite,
so I'll replace the broken one with a Sapim CX-RAY straight spoke
that has the same butted section dimensions and spoke density.
When I pulled out the nipple from the side
where the spoke had broken,
the fractured spoke head
was still stuck inside.
↑That piece
I recovered the broken spoke.
If this nipple were to drop inside the rim,
I'd have to remove the tubular tire,
which would multiply the work required.
This nipple has a 3.2mm square grip on the outer side as well,
which is normally how you'd adjust tension,
but since the customer wanted to avoid removing the tubular tire,
I'm using the inner grip.
If this were a nipple from one of those Reynolds wheels from a certain period,
the inner grip would be short and the corners oddly rounded,
making it impossible to turn once the wheel is built up under tension.
It would definitely strip.
Those are decorative, or meant only for pre-assembly.
After replacing the spoke and truing the wheel for lateral run-out,
there was a slight centering issue, which I corrected.
I'm using a Park Tool WAG-4 centering gauge
(WAG is an acronym for Wheel Alignment Gauge)
rather than my usual Hozan,
because it can measure even when the tire
overhangs the rim,
in other words, you can measure with the tire on.
However, this WAG-4 can't detect gaps
that Hozan would call a one-sheet-of-paper center offset,
so its accuracy is inferior, which is why
I don't usually use it.
It's fixed.
I asked the customer why they brought it here
instead of to the nearby Trek shop,
and they said they didn't think it could be fixed on the spot
and they don't trust their technical ability.
The tire appeared to be glued on with rim cement,
and when I asked the customer, that was indeed the case (not tape).
The valve is at an angle because
the cement melted slightly from brake heat on the descent,
causing the tire to shift relative to the rim.
When this happens, the direction the tire leans
is toward you when the valve is at the top,
so the image above shows the right side of the rim.
When I asked where the customer lives,
they said they're near Mount Rokko, so I explained that
if they reverse the wheel at the summit and descend moderately,
it might correct itself,
but it could also go the other way and lean backwards.
↑The broken Aerolite and the replacement CX-RAY
↑Spoke head side
The replacement CX-RAY
is a threadless 310mm spoke
with an extended plain section
that accommodates lengths up to 270mm,
and luckily,
the boundary between the butted section on the rim side
matches the original spoke almost exactly,
so even looking at the wheel afterwards,
you can't tell it's a replacement spoke.