Another day with wheels (and so on).
A customer brought in the front wheel of a Rolf Vector Pro for repair.
It's hard to tell because of the paired spokes, but
one spoke is broken.
We could just repair this one spoke, but...
Rolf Prima explicitly states: "For Rolf repairs, ask Trek. Rolf Prima takes no responsibility for Rolf repairs."
I don't know if Trek stocks spokes for this, but the customer wants us to handle it at our shop.
As I'll explain later, this Rolf appears to be an early model, possibly from before Rolf came under the Trek umbrella.
The spokes are DT (Deutsch Tect) brand, but they're incredibly rare—not a standard item.
The spoke didn't break at the head but near where the threads begin.
It's not precisely at the thread start because that's where the internal nipple's end face is.
So, calculating the spoke weight ratio of this spoke, accounting for the length of the broken threaded section—it came out to about 120%. I initially suspected a calculation error, but it's correct. The problem with this is that when you replace just one spoke for repair, you need to match the spoke weight ratio with the other original spokes.
DT and Sapim have spokes where the butted section dimensions are almost identical, and thus the spoke weight ratios are also nearly the same. Competition and Race, Aero Lite and CX-RAY, New Aero and CX fall into this category. With these pairs, even if the manufacturer differs, there's no particular problem during repair. New Aero and CX have a spoke weight ratio of about 100%, so if you don't mind the appearance, you can also repair with #14 plain (100% weight ratio).
The problem when spokes with different weight ratios get mixed is that the deformation amount differs at that point, causing the spoke breakage to reoccur. It's also theoretically bad for the wheel.
Taken to an extreme, if you repair this one spoke with CX-RAY (spoke weight ratio about 65%), once you true the wheel, that spot alone becomes incredibly tight. (Though once you get it trued, whether you can even tension it that much is questionable.)
Conversely, if you mix just one CX spoke into a wheel built entirely with CX-RAY, once you true it, just that CX becomes so loose it moves around. When you bring it to proper tension, you'd have to make both neighboring CX-RAYs incredibly tight, which at that phase creates radial runout on the inboard side and causes large variance in spoke tension.
So if there were spokes with about 120% weight ratio, we could just repair with one, but since no such thing exists, we have no choice but to replace all the spokes. This spoke is 283mm, and fortunately we were able to source Sapim CX in that length from our distributor.
P.S.: I received a comment suggesting that some mama-chari (utility bikes) use spokes with #14 threads and #13 gauge elsewhere, which might be around 120%. However, calculations show that would come out to around 136%.
By the way, calculating spoke weight ratio using manufacturer's published weights: Sapim CX at 260mm/64 spokes/423g gives 0.989131..., about 99%. But from actual measurements of various lengths, it comes out to around 100.8%-101%. DT New Aero is 264mm/64 spokes/437g, giving 1.006385..., about 101%. The measured values for New Aero are unknown, but from the butted section dimensions, it's certain to be almost the same as CX. And it's also certain that these spokes are not about 120% weight ratio.
Since this wheel is in regular use by the customer, I suggested that if they needed it immediately, we could do a makeshift repair with Sapim Strong (barely possible), but they decided to wait for the full CX replacement, so we didn't use Strong. Strong has #13 at the head and #14 thereafter, single-butted, with the manufacturer's spec at 260mm/64 spokes/446g, giving a spoke weight ratio of 104.3%. We can't really treat it as equivalent to a 120% spoke, but I thought it would work for temporary use.
Previously, with a Bora WTO where a spoke got bent before spare spokes were available, we did a makeshift repair with Bora spokes and properly fixed it later when WTO spokes arrived. That time too, we got subtle radial runout from the spoke mismatch. The customer said they couldn't feel it while riding though.
The holes on the rim's outer perimeter are somewhat crudely shaped, as if two round holes were drilled and then connected linearly. The spokes protrude from the internal nipples, but this was probably intentional.
I disassembled the wheel. The original unbroken spokes at 283mm/13 spokes weigh 113g, giving a spoke weight ratio of 1.195131..., so indeed about 119-120%. What on earth is this? The butted section width is ordinary, but the thickness is extraordinarily thick.
The rim's measured weight. With few spokes and extremely high tension, a sturdy—and thus heavy—rim is inevitable.
From this, I can really see how ridiculously specced the Shimano C24 front wheel is—a low-profile rim of about 390g, paired with paired spokes, built at 16H (only two more spokes than this wheel) with lightweight spokes at about 65% weight ratio—the "want-it-all aero-and-light" set. (Note: "want-it-all" doesn't include "stiffness.")
※The "want-it-all" list doesn't include "stiffness," mind you.
↑Left image is CX, right is the original spoke. The original spoke isn't extremely long, but the thread section is slightly longer.
CX will be cut from here and the threads re-rolled, and the thread length produced by a spoke cutter is subtly different from Sapim's off-the-shelf version. But compared to how long the Rolf spoke is, the difference is negligible.
Between the internal nipple and rim was a spacer or tall washer.
The nipple's contact face with the rim is
flat, not rounded, and the washer is flat on both sides. Unlike nipples with rounded bottoms and washers with one concave side that function like a ball joint to absorb spoke angle bending, this has no such function. The washer's base area is about the same as the nipple's, so the only point to having this washer is to prevent nipple rotation from transferring to the rim.
With the original spoke's slightly longer thread section, I confirmed that it has some thread remaining against the nipple's inner edge face. The broken spoke makes this obvious.
↑The original state looks like this in diagram form. Since the spoke protruded from the nipple, I could grab the broken section with a vise clamp and recover it.
If I cut the CX to the same 283mm as the original spoke, there's a risk of using up all the threads. So I set it to 282mm so that the "thread start length" matches the original spoke. This way, when assembled, the threads won't be completely used, and the spoke end should be flush with the nipple.
But as I'll explain later, it actually protruded slightly (though the threads definitely weren't used up). Since under-tensioning makes pulling-away easier, and given the CX has a smaller weight ratio than the original, I tensioned quite carefully and deliberately. But according to the customer—who watched us build this wheel—the rebuilt wheel is stiffer than the original. So the spoke pull-in must be greater than before.
Also, in the diagram, I drew the CX's plain section longer than the original, and while that's factually true, the original spoke's batted section boundary was nearly flush with the rim hole, and CX was somewhat better but still pretty tight.
The hub body logo is from early Rolf,
(For reference, the Rolf you commonly see looks like this)
It's actually a DT "Fugi" (Fuji) brand hub. The bearing diameter isn't unnecessarily small, and despite this wheel seeing considerable years of use, the rotation is smooth.
Why did I write "isn't unnecessarily small"? Because the Rolf Prima White Industries wide small-flange front hub frequently—or rather, constantly—has bearings that feel gritty. I saw one today on another job, actually. There's no way those Rolf Prima hubs have more years of use than this Rolf.
I've mentioned it here before, but I own a Fugi rear hub myself.
An 18H rear hub is extremely rare.
The rim holes have clear vertical alignment, arranged front-to-back. Some XEROLITE wheels have paired spoke rim holes aligned side-to-side.
I threaded plain spokes through the left and right flange holes. There's zero phase offset. So the spokes run parallel to the hub shell. But since the rim holes are arranged front-to-back, the 0-cross lacing pattern of this front wheel doesn't follow a truly radial trajectory—the spokes' path deviates from radial lines. Looking at the wheel from the side, the flanges appear twisted in opposite directions on the near and far sides, with the spoke path twisting. Put in extreme terms, it's like taking a JIS-pattern wheel and keeping only the non-crossed spokes.
It's built. The opening image was shot from the left side, but this image is from the right side. As for what distinguishes left from right on this rim—
The sticker has elaborate design—
On the right side you read Rolf→Vector Pro, and
on the left side it reads Vector Pro→Rolf. Also, the CX spoke plain section protrusion is as shown in the image.
This wheel obsessively pursues reducing spoke count alone, adopting spokes with about 120% weight ratio and paired spoke configuration, but Mavic's Cosmic Carbone uses #13 base spokes from the first generation (first gen was 16H front and rear, later rear-only 20H) all the way to the rear left spoke thread section of the Cosmic Carbone Ultimatum. If this Rolf had used #13 base spokes, the thread-section fracture might not have happened. But precisely because it used #14, we could repair with standard spokes (though it became a full replacement) and can henceforth repair with CX. We procured CX in quantities well beyond the bare minimum needed to rebuild this wheel. And even if spoke thread-section breaking happened again in the future and we couldn't retrieve the broken remnant from the nipple, we have inventory of nearly identical nipples (same #3/16" tool size), so there's no situation where we couldn't fix it.
A customer brought in the front wheel of a Rolf Vector Pro for repair.
It's hard to tell because of the paired spokes, but
one spoke is broken.
We could just repair this one spoke, but...
Rolf Prima explicitly states: "For Rolf repairs, ask Trek. Rolf Prima takes no responsibility for Rolf repairs."
I don't know if Trek stocks spokes for this, but the customer wants us to handle it at our shop.
As I'll explain later, this Rolf appears to be an early model, possibly from before Rolf came under the Trek umbrella.
The spokes are DT (Deutsch Tect) brand, but they're incredibly rare—not a standard item.
The spoke didn't break at the head but near where the threads begin.
It's not precisely at the thread start because that's where the internal nipple's end face is.
So, calculating the spoke weight ratio of this spoke, accounting for the length of the broken threaded section—it came out to about 120%. I initially suspected a calculation error, but it's correct. The problem with this is that when you replace just one spoke for repair, you need to match the spoke weight ratio with the other original spokes.
DT and Sapim have spokes where the butted section dimensions are almost identical, and thus the spoke weight ratios are also nearly the same. Competition and Race, Aero Lite and CX-RAY, New Aero and CX fall into this category. With these pairs, even if the manufacturer differs, there's no particular problem during repair. New Aero and CX have a spoke weight ratio of about 100%, so if you don't mind the appearance, you can also repair with #14 plain (100% weight ratio).
The problem when spokes with different weight ratios get mixed is that the deformation amount differs at that point, causing the spoke breakage to reoccur. It's also theoretically bad for the wheel.
Taken to an extreme, if you repair this one spoke with CX-RAY (spoke weight ratio about 65%), once you true the wheel, that spot alone becomes incredibly tight. (Though once you get it trued, whether you can even tension it that much is questionable.)
Conversely, if you mix just one CX spoke into a wheel built entirely with CX-RAY, once you true it, just that CX becomes so loose it moves around. When you bring it to proper tension, you'd have to make both neighboring CX-RAYs incredibly tight, which at that phase creates radial runout on the inboard side and causes large variance in spoke tension.
So if there were spokes with about 120% weight ratio, we could just repair with one, but since no such thing exists, we have no choice but to replace all the spokes. This spoke is 283mm, and fortunately we were able to source Sapim CX in that length from our distributor.
P.S.: I received a comment suggesting that some mama-chari (utility bikes) use spokes with #14 threads and #13 gauge elsewhere, which might be around 120%. However, calculations show that would come out to around 136%.
By the way, calculating spoke weight ratio using manufacturer's published weights: Sapim CX at 260mm/64 spokes/423g gives 0.989131..., about 99%. But from actual measurements of various lengths, it comes out to around 100.8%-101%. DT New Aero is 264mm/64 spokes/437g, giving 1.006385..., about 101%. The measured values for New Aero are unknown, but from the butted section dimensions, it's certain to be almost the same as CX. And it's also certain that these spokes are not about 120% weight ratio.
Since this wheel is in regular use by the customer, I suggested that if they needed it immediately, we could do a makeshift repair with Sapim Strong (barely possible), but they decided to wait for the full CX replacement, so we didn't use Strong. Strong has #13 at the head and #14 thereafter, single-butted, with the manufacturer's spec at 260mm/64 spokes/446g, giving a spoke weight ratio of 104.3%. We can't really treat it as equivalent to a 120% spoke, but I thought it would work for temporary use.
Previously, with a Bora WTO where a spoke got bent before spare spokes were available, we did a makeshift repair with Bora spokes and properly fixed it later when WTO spokes arrived. That time too, we got subtle radial runout from the spoke mismatch. The customer said they couldn't feel it while riding though.
The holes on the rim's outer perimeter are somewhat crudely shaped, as if two round holes were drilled and then connected linearly. The spokes protrude from the internal nipples, but this was probably intentional.
I disassembled the wheel. The original unbroken spokes at 283mm/13 spokes weigh 113g, giving a spoke weight ratio of 1.195131..., so indeed about 119-120%. What on earth is this? The butted section width is ordinary, but the thickness is extraordinarily thick.
The rim's measured weight. With few spokes and extremely high tension, a sturdy—and thus heavy—rim is inevitable.
From this, I can really see how ridiculously specced the Shimano C24 front wheel is—a low-profile rim of about 390g, paired with paired spokes, built at 16H (only two more spokes than this wheel) with lightweight spokes at about 65% weight ratio—the "want-it-all aero-and-light" set. (Note: "want-it-all" doesn't include "stiffness.")
※The "want-it-all" list doesn't include "stiffness," mind you.
↑Left image is CX, right is the original spoke. The original spoke isn't extremely long, but the thread section is slightly longer.
CX will be cut from here and the threads re-rolled, and the thread length produced by a spoke cutter is subtly different from Sapim's off-the-shelf version. But compared to how long the Rolf spoke is, the difference is negligible.
Between the internal nipple and rim was a spacer or tall washer.
The nipple's contact face with the rim is
flat, not rounded, and the washer is flat on both sides. Unlike nipples with rounded bottoms and washers with one concave side that function like a ball joint to absorb spoke angle bending, this has no such function. The washer's base area is about the same as the nipple's, so the only point to having this washer is to prevent nipple rotation from transferring to the rim.
With the original spoke's slightly longer thread section, I confirmed that it has some thread remaining against the nipple's inner edge face. The broken spoke makes this obvious.
↑The original state looks like this in diagram form. Since the spoke protruded from the nipple, I could grab the broken section with a vise clamp and recover it.
If I cut the CX to the same 283mm as the original spoke, there's a risk of using up all the threads. So I set it to 282mm so that the "thread start length" matches the original spoke. This way, when assembled, the threads won't be completely used, and the spoke end should be flush with the nipple.
But as I'll explain later, it actually protruded slightly (though the threads definitely weren't used up). Since under-tensioning makes pulling-away easier, and given the CX has a smaller weight ratio than the original, I tensioned quite carefully and deliberately. But according to the customer—who watched us build this wheel—the rebuilt wheel is stiffer than the original. So the spoke pull-in must be greater than before.
Also, in the diagram, I drew the CX's plain section longer than the original, and while that's factually true, the original spoke's batted section boundary was nearly flush with the rim hole, and CX was somewhat better but still pretty tight.
The hub body logo is from early Rolf,
(For reference, the Rolf you commonly see looks like this)
It's actually a DT "Fugi" (Fuji) brand hub. The bearing diameter isn't unnecessarily small, and despite this wheel seeing considerable years of use, the rotation is smooth.
Why did I write "isn't unnecessarily small"? Because the Rolf Prima White Industries wide small-flange front hub frequently—or rather, constantly—has bearings that feel gritty. I saw one today on another job, actually. There's no way those Rolf Prima hubs have more years of use than this Rolf.
I've mentioned it here before, but I own a Fugi rear hub myself.
An 18H rear hub is extremely rare.
The rim holes have clear vertical alignment, arranged front-to-back. Some XEROLITE wheels have paired spoke rim holes aligned side-to-side.
I threaded plain spokes through the left and right flange holes. There's zero phase offset. So the spokes run parallel to the hub shell. But since the rim holes are arranged front-to-back, the 0-cross lacing pattern of this front wheel doesn't follow a truly radial trajectory—the spokes' path deviates from radial lines. Looking at the wheel from the side, the flanges appear twisted in opposite directions on the near and far sides, with the spoke path twisting. Put in extreme terms, it's like taking a JIS-pattern wheel and keeping only the non-crossed spokes.
It's built. The opening image was shot from the left side, but this image is from the right side. As for what distinguishes left from right on this rim—
The sticker has elaborate design—
On the right side you read Rolf→Vector Pro, and
on the left side it reads Vector Pro→Rolf. Also, the CX spoke plain section protrusion is as shown in the image.
This wheel obsessively pursues reducing spoke count alone, adopting spokes with about 120% weight ratio and paired spoke configuration, but Mavic's Cosmic Carbone uses #13 base spokes from the first generation (first gen was 16H front and rear, later rear-only 20H) all the way to the rear left spoke thread section of the Cosmic Carbone Ultimatum. If this Rolf had used #13 base spokes, the thread-section fracture might not have happened. But precisely because it used #14, we could repair with standard spokes (though it became a full replacement) and can henceforth repair with CX. We procured CX in quantities well beyond the bare minimum needed to rebuild this wheel. And even if spoke thread-section breaking happened again in the future and we couldn't retrieve the broken remnant from the nipple, we have inventory of nearly identical nipples (same #3/16" tool size), so there's no situation where we couldn't fix it.