Another day, another wheel (et cetera).
A customer brought in a Roviàl Rapidé CLX and I've received both front and rear wheels.
Today I'm rebuilding the front wheel.
Most Roviàl disc brake front wheels use a 2:1 spoke pattern with 3-spoke pairs—7 pairs for 21 spokes total.
This front wheel, however, has only 6 pairs for 18 spokes.
Also, while wheels like the CLX50 use a tangent-laced side with 2-cross XI (X-I) lacing,
the Rapidé CLX uses 1-cross J (Jay) lacing instead.
Both sides had black Aerolite spokes, so I disassembled the wheel,
swapped the spoke-sparse side to black CX Sprint spokes,
and adjusted the spoke tension on the spoke-rich side to roughly match what it was before disassembly.
I trued both radial and lateral runout pretty well.
The image above shows where I marked the position of the spoke-sparse side (right side) hub end with a centering gauge.
I'll refer to this position as point A going forward.
When I apply position A to the left side,
there's this much center offset.
From here, I can tighten only the right-side nipples
until the center is perfect.
There are limits, but center offset is a bonus when you're tightening.
It would be impossible to create this situation while keeping both sides with the same spoke count,
because at this point the spoke-rich side tension already matches the original perfectly-centered wheel.
From here, I tightened the 6 right-side nipples
exactly one full turn each.
Then I held the saved position A
against the right hub end.
This gap shows how much the rim moved with one full turn of the nipples.
I marked the right hub end position again.
I'll call this position B from now on.
I applied position B to the left side.
This is the amount of center offset at this point.
I tightened the right-side nipples exactly one more full turn
and held the centering gauge to the right side.
↑This is the rim movement from the second tightening.
I won't quote the position where this gap reaches zero as point C.
At this point, the rim position has passed the wheel center and
the direction of offset has reversed.
↑The center offset at this point.
To close this gap, I could either back off
the nipples I just tightened two full turns, or tighten the spoke-rich side.
But since I brought the spoke-rich side back to its original tension
and then tightened the spoke-sparse side by two full turns,
the spoke-rich side tension has risen slightly as well.
While it's not impossible to close this gap by tightening the spoke-rich side further,
it's better not to.
This corresponds to the "limit" I mentioned earlier regarding
using center offset as a tightening bonus.
I loosened the spoke-sparse side to get the center right.
In the end, from point A I tightened the spoke-sparse side
about 1 and 5/6 full turns.
The wheel is rebuilt.
The spoke-sparse side is using CX Sprint spokes.
The spoke-rich side has 12 spokes—the same as one side of a symmetrical 24-hole wheel—so even straight spokes could easily handle
3-cross (equivalent to 6-spoke pairs), and certainly 2-cross (equivalent to 4-spoke pairs).
But since we're deliberately changing away from theidiotic XI lacing used on wheels like the CLX50
to J lacing, and using 1-cross (equivalent to 2-spoke pairs) lacing,
the final cross point ends up very close to the hub flange,
making the tie-in essentially meaningless
(though I won't say I've never done it before) so I'm not doing it.
The choice to use 6+12 = 18 spokes total,
and to use 1-cross tangent lacing,
is presumably all for aerodynamic performance.
But with 1-cross XI lacing, it becomes almost radial,
so they're apparently using J lacing to avoid that.
A customer brought in a Roviàl Rapidé CLX and I've received both front and rear wheels.
Today I'm rebuilding the front wheel.
Most Roviàl disc brake front wheels use a 2:1 spoke pattern with 3-spoke pairs—7 pairs for 21 spokes total.
This front wheel, however, has only 6 pairs for 18 spokes.
Also, while wheels like the CLX50 use a tangent-laced side with 2-cross XI (X-I) lacing,
the Rapidé CLX uses 1-cross J (Jay) lacing instead.
Both sides had black Aerolite spokes, so I disassembled the wheel,
swapped the spoke-sparse side to black CX Sprint spokes,
and adjusted the spoke tension on the spoke-rich side to roughly match what it was before disassembly.
I trued both radial and lateral runout pretty well.
The image above shows where I marked the position of the spoke-sparse side (right side) hub end with a centering gauge.
I'll refer to this position as point A going forward.
When I apply position A to the left side,
there's this much center offset.
From here, I can tighten only the right-side nipples
until the center is perfect.
There are limits, but center offset is a bonus when you're tightening.
It would be impossible to create this situation while keeping both sides with the same spoke count,
because at this point the spoke-rich side tension already matches the original perfectly-centered wheel.
From here, I tightened the 6 right-side nipples
exactly one full turn each.
Then I held the saved position A
against the right hub end.
This gap shows how much the rim moved with one full turn of the nipples.
I marked the right hub end position again.
I'll call this position B from now on.
I applied position B to the left side.
This is the amount of center offset at this point.
I tightened the right-side nipples exactly one more full turn
and held the centering gauge to the right side.
↑This is the rim movement from the second tightening.
I won't quote the position where this gap reaches zero as point C.
At this point, the rim position has passed the wheel center and
the direction of offset has reversed.
↑The center offset at this point.
To close this gap, I could either back off
the nipples I just tightened two full turns, or tighten the spoke-rich side.
But since I brought the spoke-rich side back to its original tension
and then tightened the spoke-sparse side by two full turns,
the spoke-rich side tension has risen slightly as well.
While it's not impossible to close this gap by tightening the spoke-rich side further,
it's better not to.
This corresponds to the "limit" I mentioned earlier regarding
using center offset as a tightening bonus.
I loosened the spoke-sparse side to get the center right.
In the end, from point A I tightened the spoke-sparse side
about 1 and 5/6 full turns.
The wheel is rebuilt.
The spoke-sparse side is using CX Sprint spokes.
The spoke-rich side has 12 spokes—the same as one side of a symmetrical 24-hole wheel—so even straight spokes could easily handle
3-cross (equivalent to 6-spoke pairs), and certainly 2-cross (equivalent to 4-spoke pairs).
But since we're deliberately changing away from the
to J lacing, and using 1-cross (equivalent to 2-spoke pairs) lacing,
the final cross point ends up very close to the hub flange,
making the tie-in essentially meaningless
(though I won't say I've never done it before) so I'm not doing it.
The choice to use 6+12 = 18 spokes total,
and to use 1-cross tangent lacing,
is presumably all for aerodynamic performance.
But with 1-cross XI lacing, it becomes almost radial,
so they're apparently using J lacing to avoid that.