A customer brought in the rear wheel of a Princeton WAKE6560 for me to work on.
I had previously replaced the front wheel bearings (→here),
and the rear wheel has play in the hub axle.
From what I could see, rather than lateral play,
the hub rotation itself was rough,
and I suspected that at least one of the four bearings—
the left and right sides of the hub body and the front and rear of the freebody—
had gone bad.
WAKE is the model name,
and 6560 refers to the wavy profile shape with 65mm and 60mm heights.
Recently Fulcrum has released wheels that look like they might upset Princeton,
but I wonder if that's okay.
The customer mentioned that when they tried to apply grease to the freebody,
they disassembled the hub and found an O-ring had snapped,
and asked me to prepare a replacement for it as well.
When I looked at the linked front wheel article, there were still things I didn't fully understand,
but ultra-thin spacers and this O-ring turned out to be critical functional parts.
Tactic Racing is a hub brand, and on Princeton's maker website,
when you select wheel specifications,
it sits quietly among well-known hub makers like
DT, Chris King, and White Industries,
but it's actually a hub brand of Princeton Carbon Works.
Product-wise, rather than being quality-built and robust,
they're obsessed with cheap weight reduction that ignores durability,
and while the vector is slightly different, they have the same odor as ExtraLite hubs.
The problems occurring in this hub
wouldn't almost certainly happen with DT or Chris King hubs under the same usage conditions.
If I knew about this hub's structure beforehand
and ordered a Princeton wheel, I wouldn't choose Tactic hubs.
While it's true that Tactic hubs are light in weight,
I'd probably choose DT instead.
The gap around the left pinned end is already rust-colored.
I called it a pinned end, but the dimensional tolerance between
the hub axle's outer diameter and the pinned end's inner diameter
is tight enough to be called an interference fit.
Unless it's right after the pinned end is set up,
it often can't be removed without proper tools.
I removed the left pinned end.
There's rust bloom on the surface that was against the bearing.
↑Hub body left side after removing the end
Rust, oil, and sand had accumulated as a clay-like dirt.
In the image above, I've wiped it away only on the left half.
～About Non-Standard Bearings～
The bearing in the image above is the standard bearing 6803.
Using the notation for non-standard bearings where you list inner diameter/outer diameter/width in millimeters: 172265.
"Sports cycling" being the mechanical sport that frequently uses bearings with outer diameters up to about 30mm,
various non-standard bearings have emerged from the sports cycling world
that slightly modify either the inner or outer diameter from standard bearings.
Most industrial products choose their dimensions based on existing standard bearings for cost reasons,
but in the sports cycling world, non-standard bearings are sometimes made
because the demand justifies the cost, or the dimensions are special.
Shimano's HG freebody uses a structure in Shimano hubs that's like an extension of the Freewheel Hub
(or rather, that's how it originated),
but with almost all other manufacturers, two cartridge bearings are installed.
These were initially often 6902—that is, 152287—
but with an outer diameter of 28mm, the wall thickness of the valley of the freebody's spline becomes extremely thin,
so they thought "I wish there was a bearing that was 6902 but with just the outer diameter changed to 26mm,
but there's no such standard bearing,"
and that's how 152267 was made.
This was definitely first developed because the bicycle world demanded it.
Since a 12mm outer diameter through-axle passes through the rear hub axle,
the hub axle's inner diameter is 12mm, and with a 12mm inner diameter hub axle,
15mm outer diameter isn't impossible but 17mm is preferable,
so 6903—that is, 173307—is often used.
However, Mavic's Instant Drive 360 hub has a portion of the hub axle that's outboard at 18mm,
and a bearing 183307 made from 6903 but with just the inner diameter changed to 18mm is used.
Incidentally, an inner diameter of 18mm is a dimension that doesn't naturally exist in any standard bearing.
What's in Shimano's original Hollowtech II BB is 6805—that is, 253377.
A plastic cover is placed over this 25mm inner diameter
to reduce the inner diameter to 24mm, allowing the 24mm outer diameter crankshaft
to pass through without metal-to-metal contact.
With Campagnolo's UltraTorque, the crankshaft outer diameter is 25mm
and appears to pass directly through 6805,
but the bearing in UltraTorque's crankarm root is
"6805 but with just the width changed to 6mm"—
in other words, 253376.
They must have had some design constraint that absolutely required reducing the thickness by 1mm.
I don't think it was meant to prevent repair with generic bearings—
it's just how it is.
Recently I was surprised to see
a bearing in a T47 spec BB where they've made 243377—
6805 with just the inner diameter changed to 24mm—
and the Shimano crankshaft passes through it in direct contact with the bearing's inner race.
BB30 comes from the 30mm crankshaft outer diameter,
and Cannondale's original BB30, which pressed standard bearings directly into the frame and held them with C-rings,
used 6806—that is, 304277 bearing.
In this Tactic hub, the hub body right side bearing is 172287—
6903, which is 173307, but with the outer diameter reduced by 2mm.
It's quite special, but obtainable.
The other three bearings are 6803, with a 17mm outer diameter hub axle
running straight through them.
If the bearing's outer diameter were larger by 1mm in radius (2mm in diameter),
it seems the ratchet mechanism around here couldn't work.
The face ratchet spring is single-acting,
and is inside the hub body
(incidentally, DT's Ratchet EXP is on the freebody side).
The face ratchet contact surface is tapered.
↑This is a Novatech freebody, and there's a spacer that slightly protrudes dimensionally
so the freebody doesn't make face contact with the hub body bearing
(doesn't press on anything but the inner race).
↑When removed, it looks like this
The corresponding part on Tactic was plastic.
The freebody bearings aren't both inserted from the outside;
the rear bearing is inserted from the inside.
Only this bearing had loose dimensional tolerance that didn't constitute an interference fit,
allowing hand removal and installation.
This doesn't seem to be because the freebody side has worn down.
The spacer supporting the inner races of the freebody bearings on the inside is omitted.
With Neumann hubs, the pinned end is flush against the hub axle (making it stronger against through-axle over-tightening),
but there's an example where the freebody outside and hub body left side bearings fail quickly (→here).
The freebody looks like this from the outside
For the bearings, the three 6803s other than the 172287 on the hub body right side
were all damaged to varying degrees, so they needed to be replaced.
I removed the thin spacers that fit inside the left and right pinned ends.
In the image above, what's dirty is the left side surface that faced outward,
↑and the surface facing inward looks like this.
I cleaned the rust as much as possible, but
interestingly, the left side actually had two stacked.
There are several holes in the hub axle,
but these aren't drain holes; when the hub axle is inserted,
they're more likely air holes to prevent the air from becoming pressurized
due to telescoping.
There are two at 180° phase, so
looking straight through, you can see they go all the way.
This same hole isn't found on cartridge bearings, so
the bearing's inner diameter and the hub axle's outer diameter aren't
perfectly sealed together. Cup-and-cone style Shimano complete wheels' hub axles also have these holes,
and even then, the through-axle and hub axle relationship is a tight telescoping fit,
so the hole might be made with the through-axle-to-hub-axle relationship in mind
rather than the hub axle-to-hub-body relationship.
Both left and right ends are flush-mounted to the pinned relationship,
so the hub axle plus right end shown in the image above should be separable,
but they're pressed at an interference fit level and aren't easily removed.
↑The cleaned left end as viewed from the hub body contact face.
There's a protrusion that presses only the bearing's inner race, but
in reality, there's also a groove elsewhere where an O-ring attaches and an ultra-thin spacer also fits between,
so this end doesn't directly contact the bearing's inner race.
On the inside of the right end,
the original O-ring remained unbroken.
I didn't realize the importance of this when looking at the front wheel article linked before,
but it's an essential functional part of the hub structure.
↑The original is in the center of the image,
on the right is a generic part I found with the same wire diameter and inner/outer diameters,
and on the left is what I stocked just in case—
same wire diameter but inner/outer diameter 1mm larger than the one on the right.
In the image, only the original's wire diameter appears thinner,
but they're originally the same.
The ultra-thin spacer was dimensioned to just barely not touch the bearing's outer race.
↑Shifted slightly, it looks like this
I fit the generic O-ring with the same inner/outer diameter as the original into the groove.
It looks like it's sticking out,
but it ends up fitting properly.
I inserted the ultra-thin spacer.
On the right side, so just one, like the original.
↑The spacer blends into the background and is hard to see, but
when the O-ring isn't shrunken, it looks like this.
With this hub, the two side ends are first flush-mounted to the hub axle
so that even under the compression force of a through-axle,
the distance between the left and right ends doesn't change.
This eliminates the need for a spacer inside the freebody or hub body
to restrain the bearing's inner race, and allows it to endure even
a foolish specification like making the freebody flush-mount stop spacer plastic.
The distance between the left and right ends
is longer than the outer-to-outer dimension of the bearings
from the hub body left side to the freebody right side.
If the former were smaller, it would excessively press the bearing's inner race,
making the hub rotation abnormally heavy or stopping it entirely.
So the O-ring and ultra-thin spacer
work like the wave washers in play-adjustment crank sets
where the crankshaft and one crankarm are connected by bolt,
applying just the right amount of pressure to the bearing's inner race—
that's the foolish structure of this hub.
When the bearings, especially the outer two, wear and the inner race develops play
(lateral play) relative to the outer race,
and the amount of this lateral play exceeds what the O-ring and ultra-thin spacer can absorb,
then the hub axle develops play.
When I received it, I was more concerned with the rotation being rough overall
than with the hub axle play the customer mentioned,
so I didn't carefully examine the play itself,
but with this structure, even just the O-ring snapping
could cause play to appear.
When I was working on the front wheel, the customer had sent me
bearing from Tactic Racing saying "If you find a bearing that seems bad, use this,"
and I also have that bearing this time.
The 172287 on the hub body right side had no roughness in rotation,
so I didn't replace it this time.
All the other 6803s I replaced.
I replaced the most severely damaged hub body left side last,
but I ran out of the 6803 bearings the customer provided,
so I used a bearing from our shop inventory for this one.
↑The most severely damaged hub body left side bearing.
The insides are completely rusted.
When I pulled out the hub axle, there was some resistance in the freebody bearings,
and I wondered if it was rust-seizure or just tight dimensional tolerance,
I had previously replaced the front wheel bearings (→here),
and the rear wheel has play in the hub axle.
From what I could see, rather than lateral play,
the hub rotation itself was rough,
and I suspected that at least one of the four bearings—
the left and right sides of the hub body and the front and rear of the freebody—
had gone bad.
WAKE is the model name,
and 6560 refers to the wavy profile shape with 65mm and 60mm heights.
Recently Fulcrum has released wheels that look like they might upset Princeton,
but I wonder if that's okay.
The customer mentioned that when they tried to apply grease to the freebody,
they disassembled the hub and found an O-ring had snapped,
and asked me to prepare a replacement for it as well.
When I looked at the linked front wheel article, there were still things I didn't fully understand,
but ultra-thin spacers and this O-ring turned out to be critical functional parts.
Tactic Racing is a hub brand, and on Princeton's maker website,
when you select wheel specifications,
it sits quietly among well-known hub makers like
DT, Chris King, and White Industries,
but it's actually a hub brand of Princeton Carbon Works.
Product-wise, rather than being quality-built and robust,
they're obsessed with cheap weight reduction that ignores durability,
and while the vector is slightly different, they have the same odor as ExtraLite hubs.
The problems occurring in this hub
wouldn't almost certainly happen with DT or Chris King hubs under the same usage conditions.
If I knew about this hub's structure beforehand
and ordered a Princeton wheel, I wouldn't choose Tactic hubs.
While it's true that Tactic hubs are light in weight,
I'd probably choose DT instead.
The gap around the left pinned end is already rust-colored.
I called it a pinned end, but the dimensional tolerance between
the hub axle's outer diameter and the pinned end's inner diameter
is tight enough to be called an interference fit.
Unless it's right after the pinned end is set up,
it often can't be removed without proper tools.
I removed the left pinned end.
There's rust bloom on the surface that was against the bearing.
↑Hub body left side after removing the end
Rust, oil, and sand had accumulated as a clay-like dirt.
In the image above, I've wiped it away only on the left half.
～About Non-Standard Bearings～
The bearing in the image above is the standard bearing 6803.
Using the notation for non-standard bearings where you list inner diameter/outer diameter/width in millimeters: 172265.
"Sports cycling" being the mechanical sport that frequently uses bearings with outer diameters up to about 30mm,
various non-standard bearings have emerged from the sports cycling world
that slightly modify either the inner or outer diameter from standard bearings.
Most industrial products choose their dimensions based on existing standard bearings for cost reasons,
but in the sports cycling world, non-standard bearings are sometimes made
because the demand justifies the cost, or the dimensions are special.
Shimano's HG freebody uses a structure in Shimano hubs that's like an extension of the Freewheel Hub
(or rather, that's how it originated),
but with almost all other manufacturers, two cartridge bearings are installed.
These were initially often 6902—that is, 152287—
but with an outer diameter of 28mm, the wall thickness of the valley of the freebody's spline becomes extremely thin,
so they thought "I wish there was a bearing that was 6902 but with just the outer diameter changed to 26mm,
but there's no such standard bearing,"
and that's how 152267 was made.
This was definitely first developed because the bicycle world demanded it.
Since a 12mm outer diameter through-axle passes through the rear hub axle,
the hub axle's inner diameter is 12mm, and with a 12mm inner diameter hub axle,
15mm outer diameter isn't impossible but 17mm is preferable,
so 6903—that is, 173307—is often used.
However, Mavic's Instant Drive 360 hub has a portion of the hub axle that's outboard at 18mm,
and a bearing 183307 made from 6903 but with just the inner diameter changed to 18mm is used.
Incidentally, an inner diameter of 18mm is a dimension that doesn't naturally exist in any standard bearing.
What's in Shimano's original Hollowtech II BB is 6805—that is, 253377.
A plastic cover is placed over this 25mm inner diameter
to reduce the inner diameter to 24mm, allowing the 24mm outer diameter crankshaft
to pass through without metal-to-metal contact.
With Campagnolo's UltraTorque, the crankshaft outer diameter is 25mm
and appears to pass directly through 6805,
but the bearing in UltraTorque's crankarm root is
"6805 but with just the width changed to 6mm"—
in other words, 253376.
They must have had some design constraint that absolutely required reducing the thickness by 1mm.
I don't think it was meant to prevent repair with generic bearings—
it's just how it is.
Recently I was surprised to see
a bearing in a T47 spec BB where they've made 243377—
6805 with just the inner diameter changed to 24mm—
and the Shimano crankshaft passes through it in direct contact with the bearing's inner race.
BB30 comes from the 30mm crankshaft outer diameter,
and Cannondale's original BB30, which pressed standard bearings directly into the frame and held them with C-rings,
used 6806—that is, 304277 bearing.
In this Tactic hub, the hub body right side bearing is 172287—
6903, which is 173307, but with the outer diameter reduced by 2mm.
It's quite special, but obtainable.
The other three bearings are 6803, with a 17mm outer diameter hub axle
running straight through them.
If the bearing's outer diameter were larger by 1mm in radius (2mm in diameter),
it seems the ratchet mechanism around here couldn't work.
The face ratchet spring is single-acting,
and is inside the hub body
(incidentally, DT's Ratchet EXP is on the freebody side).
The face ratchet contact surface is tapered.
↑This is a Novatech freebody, and there's a spacer that slightly protrudes dimensionally
so the freebody doesn't make face contact with the hub body bearing
(doesn't press on anything but the inner race).
↑When removed, it looks like this
The corresponding part on Tactic was plastic.
The freebody bearings aren't both inserted from the outside;
the rear bearing is inserted from the inside.
Only this bearing had loose dimensional tolerance that didn't constitute an interference fit,
allowing hand removal and installation.
This doesn't seem to be because the freebody side has worn down.
The spacer supporting the inner races of the freebody bearings on the inside is omitted.
With Neumann hubs, the pinned end is flush against the hub axle (making it stronger against through-axle over-tightening),
but there's an example where the freebody outside and hub body left side bearings fail quickly (→here).
The freebody looks like this from the outside
For the bearings, the three 6803s other than the 172287 on the hub body right side
were all damaged to varying degrees, so they needed to be replaced.
I removed the thin spacers that fit inside the left and right pinned ends.
In the image above, what's dirty is the left side surface that faced outward,
↑and the surface facing inward looks like this.
I cleaned the rust as much as possible, but
interestingly, the left side actually had two stacked.
There are several holes in the hub axle,
but these aren't drain holes; when the hub axle is inserted,
they're more likely air holes to prevent the air from becoming pressurized
due to telescoping.
There are two at 180° phase, so
looking straight through, you can see they go all the way.
This same hole isn't found on cartridge bearings, so
the bearing's inner diameter and the hub axle's outer diameter aren't
perfectly sealed together. Cup-and-cone style Shimano complete wheels' hub axles also have these holes,
and even then, the through-axle and hub axle relationship is a tight telescoping fit,
so the hole might be made with the through-axle-to-hub-axle relationship in mind
rather than the hub axle-to-hub-body relationship.
Both left and right ends are flush-mounted to the pinned relationship,
so the hub axle plus right end shown in the image above should be separable,
but they're pressed at an interference fit level and aren't easily removed.
↑The cleaned left end as viewed from the hub body contact face.
There's a protrusion that presses only the bearing's inner race, but
in reality, there's also a groove elsewhere where an O-ring attaches and an ultra-thin spacer also fits between,
so this end doesn't directly contact the bearing's inner race.
On the inside of the right end,
the original O-ring remained unbroken.
I didn't realize the importance of this when looking at the front wheel article linked before,
but it's an essential functional part of the hub structure.
↑The original is in the center of the image,
on the right is a generic part I found with the same wire diameter and inner/outer diameters,
and on the left is what I stocked just in case—
same wire diameter but inner/outer diameter 1mm larger than the one on the right.
In the image, only the original's wire diameter appears thinner,
but they're originally the same.
The ultra-thin spacer was dimensioned to just barely not touch the bearing's outer race.
↑Shifted slightly, it looks like this
I fit the generic O-ring with the same inner/outer diameter as the original into the groove.
It looks like it's sticking out,
but it ends up fitting properly.
I inserted the ultra-thin spacer.
On the right side, so just one, like the original.
↑The spacer blends into the background and is hard to see, but
when the O-ring isn't shrunken, it looks like this.
With this hub, the two side ends are first flush-mounted to the hub axle
so that even under the compression force of a through-axle,
the distance between the left and right ends doesn't change.
This eliminates the need for a spacer inside the freebody or hub body
to restrain the bearing's inner race, and allows it to endure even
a foolish specification like making the freebody flush-mount stop spacer plastic.
The distance between the left and right ends
is longer than the outer-to-outer dimension of the bearings
from the hub body left side to the freebody right side.
If the former were smaller, it would excessively press the bearing's inner race,
making the hub rotation abnormally heavy or stopping it entirely.
So the O-ring and ultra-thin spacer
work like the wave washers in play-adjustment crank sets
where the crankshaft and one crankarm are connected by bolt,
applying just the right amount of pressure to the bearing's inner race—
that's the foolish structure of this hub.
When the bearings, especially the outer two, wear and the inner race develops play
(lateral play) relative to the outer race,
and the amount of this lateral play exceeds what the O-ring and ultra-thin spacer can absorb,
then the hub axle develops play.
When I received it, I was more concerned with the rotation being rough overall
than with the hub axle play the customer mentioned,
so I didn't carefully examine the play itself,
but with this structure, even just the O-ring snapping
could cause play to appear.
When I was working on the front wheel, the customer had sent me
bearing from Tactic Racing saying "If you find a bearing that seems bad, use this,"
and I also have that bearing this time.
The 172287 on the hub body right side had no roughness in rotation,
so I didn't replace it this time.
All the other 6803s I replaced.
I replaced the most severely damaged hub body left side last,
but I ran out of the 6803 bearings the customer provided,
so I used a bearing from our shop inventory for this one.
↑The most severely damaged hub body left side bearing.
The insides are completely rusted.
When I pulled out the hub axle, there was some resistance in the freebody bearings,
and I wondered if it was rust-seizure or just tight dimensional tolerance,
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