A customer brought me an Intense complete bike's stock wheel for service.
Intense is an MTB frame brand, and
based on my knowledge of Intense from the early 2000s and before,
their forks were often Marzocchi,
but this wheel came stock on a limited edition complete bike
that was a collaboration with DVO (a suspension brand),
and the light green color is DVO's corporate color.
Around half the rim's circumference
there's an Inte
nse
decal, and it's repeated twice around the entire rim circumference.
The rim is a low-profile wide rim made of carbon fiber,
the hub is a 350 disc with 28H, all black competition-grade lacing.
A DT 14mm length nipple has fractured.
There are also scratch marks on the rim surface.
This kind of fracture isn't unheard of,
but it's been happening frequently on this wheel.
The biggest cause of this is
the use of nipple washers.
I think they wanted to distribute
the spoke tension load on the carbon rim's spoke holes,
but with something like a PHR washer, if you use
Squorx nipples that have reinforced contact areas
matching the washer thickness,
this kind of fracture virtually never happens.
Use a regular nipple with a nipple washer,
and the fracture risk skyrockets.
I specify the use of PHR washer + Squorx nipples
on DT's RR411 rim and XR331 rim,
and since Squorx nipples only come in silver and black back then
(nowadays red has been added),
I've built wheels with other color nipples + PHR washers,
and both on my own wheels and customers' wheels,
nipple fractures occurred in an unusually short timeframe,
something that normally wouldn't happen at all.
I had to take back all those wheels that were built without Squorx nipples
and rebuild them all for free.
There's no sign of sealant flowing into the rim,
but condensation might have formed at some point.
Most of the nipples were corroded.
The potential difference between the washer material might be a factor too.
Short spokes also relate to fracture risk.
There's a clear difference in fracture risk depending on whether
the spoke end is flush with the slot or flush with the nipple end itself.
Experience shows the latter is less prone to fracture,
and this wheel falls into the former category.
↑Original 14mm nipple
↑DT 12mm black aluminum nipple
Actually, this wheel has already had
several fractured nipples replaced at my shop.
The replaced nipples have never fractured again.
The fracture at the beginning happened when the customer
took the wheel home and was installing a tire,
when suddenly it went snap! and fractured.
That finally convinced them to do a complete replacement.
↑The DT 12mm nipples
are installed without washers.
The threads should advance by the washer thickness,
yet they still look short.
Well, since the washer is the main cause of fracture,
I'm not doing a complete spoke replacement
in conjunction with this nipple replacement.
↑Previously replaced nipples
(these aren't all of them)
Hardened thread-locking compound was packed
into the thread valleys,
and while it provided some loosening resistance on initial nipple rotation,
it actually caused the spokes to twist.
I broke out and removed all of that hardened compound.
↑The carbon rim's weight.
I don't have a standard in my mind
for whether this type of rim is light or heavy.
Rebuilt it.
Replaced the nipples.
The parts that were already DT I reused.
I didn't want it to feel like double-charging,
so I deducted the previous nipple replacement charge
from today's wheel building labor fee.
Intense is an MTB frame brand, and
based on my knowledge of Intense from the early 2000s and before,
their forks were often Marzocchi,
but this wheel came stock on a limited edition complete bike
that was a collaboration with DVO (a suspension brand),
and the light green color is DVO's corporate color.
Around half the rim's circumference
there's an Inte
nse
decal, and it's repeated twice around the entire rim circumference.
The rim is a low-profile wide rim made of carbon fiber,
the hub is a 350 disc with 28H, all black competition-grade lacing.
A DT 14mm length nipple has fractured.
There are also scratch marks on the rim surface.
This kind of fracture isn't unheard of,
but it's been happening frequently on this wheel.
The biggest cause of this is
the use of nipple washers.
I think they wanted to distribute
the spoke tension load on the carbon rim's spoke holes,
but with something like a PHR washer, if you use
Squorx nipples that have reinforced contact areas
matching the washer thickness,
this kind of fracture virtually never happens.
Use a regular nipple with a nipple washer,
and the fracture risk skyrockets.
I specify the use of PHR washer + Squorx nipples
on DT's RR411 rim and XR331 rim,
and since Squorx nipples only come in silver and black back then
(nowadays red has been added),
I've built wheels with other color nipples + PHR washers,
and both on my own wheels and customers' wheels,
nipple fractures occurred in an unusually short timeframe,
something that normally wouldn't happen at all.
I had to take back all those wheels that were built without Squorx nipples
and rebuild them all for free.
There's no sign of sealant flowing into the rim,
but condensation might have formed at some point.
Most of the nipples were corroded.
The potential difference between the washer material might be a factor too.
Short spokes also relate to fracture risk.
There's a clear difference in fracture risk depending on whether
the spoke end is flush with the slot or flush with the nipple end itself.
Experience shows the latter is less prone to fracture,
and this wheel falls into the former category.
↑Original 14mm nipple
↑DT 12mm black aluminum nipple
Actually, this wheel has already had
several fractured nipples replaced at my shop.
The replaced nipples have never fractured again.
The fracture at the beginning happened when the customer
took the wheel home and was installing a tire,
when suddenly it went snap! and fractured.
That finally convinced them to do a complete replacement.
↑The DT 12mm nipples
are installed without washers.
The threads should advance by the washer thickness,
yet they still look short.
Well, since the washer is the main cause of fracture,
I'm not doing a complete spoke replacement
in conjunction with this nipple replacement.
↑Previously replaced nipples
(these aren't all of them)
Hardened thread-locking compound was packed
into the thread valleys,
and while it provided some loosening resistance on initial nipple rotation,
it actually caused the spokes to twist.
I broke out and removed all of that hardened compound.
↑The carbon rim's weight.
I don't have a standard in my mind
for whether this type of rim is light or heavy.
Rebuilt it.
Replaced the nipples.
The parts that were already DT I reused.
I didn't want it to feel like double-charging,
so I deducted the previous nipple replacement charge
from today's wheel building labor fee.