The front wheel of the Ｒｏｖａａｌ CLX50 that I reassembled the other day—after wiring it up,
I replaced the bearings.
The image above shows the CeramicSpeed bearings I removed—the outer side had a black seal, but the inside had a blue seal.
The replacement bearings are steel ball bearings, but after consulting with the customer,
I've intentionally gone with non-contact seals rather than contact seals.
Even though it's a DT hub, what's confusing to me is why DT adopted fairly large contact-type bearings in the first place—this applies to Ｒｏｖａａｌ and GIANT's SLR series wheels.
This isn't the first time I've touched on this issue, but looking at the image above, you can see that
the diameter of the bearing seat has been deliberately filled in,
forcing the use of a smaller-diameter bearing.
With a 12mm through-axle hub shaft, the outer diameter is usually 15mm,
so the bearing bore diameter is also 15mm.
The 6802 bearings used in this hub have an outer diameter of 24mm and a thickness of 5mm, but
the 6902 commonly used in DT hubs has an outer diameter of 28mm and a thickness of 7mm.
Beyond that, a 28mm outer diameter is already cutting it close for fitting into a Shimano HG freebody, and even then it's tight for the hub shell, so
there's also the 15267—a bearing that's 6902 in spec except the outer diameter has been reduced to 26mm,
creating inner diameter 15mm, outer diameter 26mm, thickness 7mm dimensions that became the part number as-is.
If this hub adopted the 6902 or 15267,
the bearing durability would improve considerably, I think....
According to NTN documentation, the 6902 is 18.1g and the 6802 is 7.0g, so
if I swapped from 6802 to 6902 for both bearings on either side,
that's a 22g weight increase for the pair, and as a result
the CLX50 Disc's stated weight of 645g would become 677g—
(↑I'm ignoring the aluminum weight reduction on the hub body side from the larger bearings)
the likelihood of being chosen by buyers who look at catalog specs drops
(a 650g wheel from another brand sells instead), which is probably why they went with the 6802.
The jump from 645g to 677g didn't cross a hundred-gram threshold, but when weight jumps across a hundred-gram boundary,
the appeal to that purchasing demographic drops significantly.
This is my bias, but except in cases where it came forced on a Specialized complete bike,
the people who deliberately choose a Ｒｏｖａａｌ wheel seem to
be buying based on catalog weight as their primary information source.
↑Yes, that one's too strong, so it's banned. I can't use it anymore going forward.
I replaced the bearings.
The image above shows the CeramicSpeed bearings I removed—the outer side had a black seal, but the inside had a blue seal.
The replacement bearings are steel ball bearings, but after consulting with the customer,
I've intentionally gone with non-contact seals rather than contact seals.
Even though it's a DT hub, what's confusing to me is why DT adopted fairly large contact-type bearings in the first place—this applies to Ｒｏｖａａｌ and GIANT's SLR series wheels.
This isn't the first time I've touched on this issue, but looking at the image above, you can see that
the diameter of the bearing seat has been deliberately filled in,
forcing the use of a smaller-diameter bearing.
With a 12mm through-axle hub shaft, the outer diameter is usually 15mm,
so the bearing bore diameter is also 15mm.
The 6802 bearings used in this hub have an outer diameter of 24mm and a thickness of 5mm, but
the 6902 commonly used in DT hubs has an outer diameter of 28mm and a thickness of 7mm.
Beyond that, a 28mm outer diameter is already cutting it close for fitting into a Shimano HG freebody, and even then it's tight for the hub shell, so
there's also the 15267—a bearing that's 6902 in spec except the outer diameter has been reduced to 26mm,
creating inner diameter 15mm, outer diameter 26mm, thickness 7mm dimensions that became the part number as-is.
If this hub adopted the 6902 or 15267,
the bearing durability would improve considerably, I think....
According to NTN documentation, the 6902 is 18.1g and the 6802 is 7.0g, so
if I swapped from 6802 to 6902 for both bearings on either side,
that's a 22g weight increase for the pair, and as a result
the CLX50 Disc's stated weight of 645g would become 677g—
(↑I'm ignoring the aluminum weight reduction on the hub body side from the larger bearings)
the likelihood of being chosen by buyers who look at catalog specs drops
(a 650g wheel from another brand sells instead), which is probably why they went with the 6802.
The jump from 645g to 677g didn't cross a hundred-gram threshold, but when weight jumps across a hundred-gram boundary,
the appeal to that purchasing demographic drops significantly.
This is my bias, but except in cases where it came forced on a Specialized complete bike,
the people who deliberately choose a Ｒｏｖａａｌ wheel seem to
be buying based on catalog weight as their primary information source.
↑Yes, that one's too strong, so it's banned. I can't use it anymore going forward.