I received a Roval CLX50 rear wheel from a customer for repairs.
Although it had been overhauled at another shop,
the rotation became sluggish and made strange noises.
The customer said it's been used only in fair weather with less than 2000 km of distance.
Given the visible wear, I suspect the 2000 km is the distance since the overhaul, not from new.
But that's not the real problem—there were so many unbelievable things done to this wheel that
after completing the repairs, I called the customer and asked,
"I'm not accusing anyone, but you didn't do this yourself, right?"
What I learned was that they'd entrusted this wheel to that shop three times,
and each time it came back with some new problem.
Regarding the hub rotation, when holding the cone end and spinning it by hand,
the rotation feels less "murky" and more like
the catching sensation of a safe dial, or rough and grinding.
This Roval hub is a DT-made star ratchet type hub,
so a special tool is essential to replace the bearing on the right side of the hub body.
The bearing there had been replaced as well.
Since few individuals buy that tool,
it's certain this was done by the shop.
I removed the left cone end.
Oil and metal particles mixed into a paste-like residue had accumulated around the bearing seal.
This is the inner face of the left cone end.
There are wear marks beyond just the step that presses the inner race,
but I'll show the cleaned image later.
I removed the right cone end.
The orange color of the freewheel bearing and the flush surface is unusually glossy
because oil is on it.
Here too, paste-like residue had adhered.
On the star ratchet face and ratchet teeth,
there's no trace of the special grease being applied.
If it had been properly applied during overhaul,
it's impossible for it to disappear completely after only 2000 km of fair-weather use.
Even with the freewheel body removed—in "front hub mode"—
the rotation is still grinding.
So the problem remains on this side.
Using the special tool for loosening the star ratchet spline,
I loosened the spline.
Before the spline, a ring with a U-shaped groove
(for forming a labyrinth seal between the freewheel body)
came out first. Japanese suppliers call this
the "water and dust seal."
I removed the spline.
I tapped out the bearing on the right side of the hub body along with the hub shaft.
There's a special tool for tapping it out too.
From the original "overhaul" nonsense,
a gray, dull-looking grease had been applied liberally.
Perhaps it's their shop's "special grease" (laughs).
State after removing the bearing on the right side of the hub body.
I inserted the hub shaft from outside into the left-side hub body bearing
and rotated it by hand. There was a grinding sensation.
This is the main culprit for the bearing problems.
Normally this bearing won't budge.
With proper tooling, it should come out with a plastic hammer impact.
This bearing sits deep, but it looks like it was driven in crooked
and hammered forcefully, creating burrs partway down the cylindrical hole.
To avoid scratching the hub body,
I threaded an old rotor lock ring onto the centerlock socket.
Using a bearing puller attachment, separate from DT's hub shaft method,
and striking repeatedly with an iron hammer,
I was able to recover it, though it came out damaged.
For DT hub bearings, you leave one as a guide for driving straight in
using the special tool with impact force,
but for the hub body without the hub shaft passing through,
you can press-fit using this special tool as a static pressure fixture.
In this case, the left side of the hub body is the better choice.
I press-fitted the left hub body bearing.
Before that, I sanded away the burrs with sandpaper.
I wiped away the contamination from the contact face of the left cone end.
There are wear marks below the step that presses just the inner race.
The lightening cutout on the left cone end was also caked with gray grease.
There's some reddish paint-like substance stuck on it, but I can't explain that.
This cone end has no rubber O-ring or similar for water protection,
so if water gets on it, the bearing seal becomes
the final line of defense immediately.
The four bearings total that were replaced in the original "overhaul" nonsense—
between the hub body and freewheel body—
all had metal-seal bearings installed.
If you run these with oil instead of grease,
you can get lighter rotation if you don't care about longevity,
which is what this setup represents. I asked the customer during that phone call
if they knew about this,
and they didn't.
With customer approval, I could explain that it's a trade-off between durability and performance,
and it would be okay to do if they consent—but this was done without permission.
They probably thought, "You don't need expensive ceramic bearings;
with these bearings you can get lighter rotation more cheaply"—what idiots.
The left-side hub body bearing showed no water intrusion or rust,
so water damage wasn't the cause,
but the fact is the rotation failed in extremely short time
on sunny days only, under 2000 km.
The bearings are both NTN,
the metal-seal version is 6902Z,
and the non-contact rubber seal version is 6902LB.
Depending on the manufacturer,
Z or ZZ indicates metal seals, LB or LLB indicates non-contact rubber seals,
and LU or LLU indicates contact rubber seals.
With contact rubber seals, there's an incomplete rule
to make the seal color orange or brown,
and NTN does make them orange.
↑You can see the 6902LU has ridges where it contacts the inner race.
This time I replaced all with non-contact rubber seal bearings.
Metal seals are also non-contact, but
within the non-contact category,
the water resistance of Z is inferior to LB.
The hub shaft passing through the left hub body bearing
serves as a guide for driving straight,
so I attached the special tool
and seated the bearing.
It protrudes slightly from the back face of the hub body,
which is the normal state.
↑This is the face of the star ratchet spline toward the hub body,
and you need to seat a washer in the depression.
If you tighten the spline with this misaligned,
it'll be a disaster (not that I've done it).
The tightening tool tip has a step that matches the washer's inner diameter,
but as you tighten,
it doesn't automatically guide itself,
so you must confirm correct placement before firmly tightening.
This is the water-dust seal ring's face toward the hub body,
and the U-shaped groove side faces outward.
There's also a special tool for driving this straight in,
and this is how you seat it.
It's strange that in the original "overhaul" nonsense, they had the tool
but had no star ratchet special grease.
Well, I don't need to understand or bother trying to.
I returned it to front hub mode again.
Rotating the hub shaft by hand, it spins smoothly without cloudiness.
The freewheel body stop spacer touching the inner race of the right hub body bearing
shows wear marks that shouldn't appear in the short term.
Below this spacer are the star ratchet parts
set up like this,
but if the hub shaft has no play or runout,
such wear marks wouldn't appear in the short term.
The star ratchet parts were the lightened version.
With DT brand wheels, when you buy a fairly high-end wheel
or order just this part separately,
you get this version.
↑This has more ratchet teeth, an even higher grade,
so naturally it's lightened.
Budget hubs have the non-lightened version.
You can't buy this part individually.
In the lightened sections of the star ratchet parts,
the pink-colored star ratchet special grease
remains in its clean color even after extended use.
On this wheel, there was none of that,
and gray grease had seeped in.
DT has a multi-purpose grease (left in the image above) separate from the star ratchet special grease,
but this is different grease from both.
The freewheel body bearings were also swapped out for 6802Z.
There was nothing wrong internally or externally,
but after consulting with the customer, we decided to replace them anyway.
I removed the inner bearing and the spacer pressing the inner race.
The gray grease, mixed with contamination,
had become cotton-like,
and I extracted it with tweezers.
Although it had been overhauled at another shop,
the rotation became sluggish and made strange noises.
The customer said it's been used only in fair weather with less than 2000 km of distance.
Given the visible wear, I suspect the 2000 km is the distance since the overhaul, not from new.
But that's not the real problem—there were so many unbelievable things done to this wheel that
after completing the repairs, I called the customer and asked,
"I'm not accusing anyone, but you didn't do this yourself, right?"
What I learned was that they'd entrusted this wheel to that shop three times,
and each time it came back with some new problem.
Regarding the hub rotation, when holding the cone end and spinning it by hand,
the rotation feels less "murky" and more like
the catching sensation of a safe dial, or rough and grinding.
This Roval hub is a DT-made star ratchet type hub,
so a special tool is essential to replace the bearing on the right side of the hub body.
The bearing there had been replaced as well.
Since few individuals buy that tool,
it's certain this was done by the shop.
I removed the left cone end.
Oil and metal particles mixed into a paste-like residue had accumulated around the bearing seal.
This is the inner face of the left cone end.
There are wear marks beyond just the step that presses the inner race,
but I'll show the cleaned image later.
I removed the right cone end.
The orange color of the freewheel bearing and the flush surface is unusually glossy
because oil is on it.
Here too, paste-like residue had adhered.
On the star ratchet face and ratchet teeth,
there's no trace of the special grease being applied.
If it had been properly applied during overhaul,
it's impossible for it to disappear completely after only 2000 km of fair-weather use.
Even with the freewheel body removed—in "front hub mode"—
the rotation is still grinding.
So the problem remains on this side.
Using the special tool for loosening the star ratchet spline,
I loosened the spline.
Before the spline, a ring with a U-shaped groove
(for forming a labyrinth seal between the freewheel body)
came out first. Japanese suppliers call this
the "water and dust seal."
I removed the spline.
I tapped out the bearing on the right side of the hub body along with the hub shaft.
There's a special tool for tapping it out too.
From the original "overhaul" nonsense,
a gray, dull-looking grease had been applied liberally.
Perhaps it's their shop's "special grease" (laughs).
State after removing the bearing on the right side of the hub body.
I inserted the hub shaft from outside into the left-side hub body bearing
and rotated it by hand. There was a grinding sensation.
This is the main culprit for the bearing problems.
Normally this bearing won't budge.
With proper tooling, it should come out with a plastic hammer impact.
This bearing sits deep, but it looks like it was driven in crooked
and hammered forcefully, creating burrs partway down the cylindrical hole.
To avoid scratching the hub body,
I threaded an old rotor lock ring onto the centerlock socket.
Using a bearing puller attachment, separate from DT's hub shaft method,
and striking repeatedly with an iron hammer,
I was able to recover it, though it came out damaged.
For DT hub bearings, you leave one as a guide for driving straight in
using the special tool with impact force,
but for the hub body without the hub shaft passing through,
you can press-fit using this special tool as a static pressure fixture.
In this case, the left side of the hub body is the better choice.
I press-fitted the left hub body bearing.
Before that, I sanded away the burrs with sandpaper.
I wiped away the contamination from the contact face of the left cone end.
There are wear marks below the step that presses just the inner race.
The lightening cutout on the left cone end was also caked with gray grease.
There's some reddish paint-like substance stuck on it, but I can't explain that.
This cone end has no rubber O-ring or similar for water protection,
so if water gets on it, the bearing seal becomes
the final line of defense immediately.
The four bearings total that were replaced in the original "overhaul" nonsense—
between the hub body and freewheel body—
all had metal-seal bearings installed.
If you run these with oil instead of grease,
you can get lighter rotation if you don't care about longevity,
which is what this setup represents. I asked the customer during that phone call
if they knew about this,
and they didn't.
With customer approval, I could explain that it's a trade-off between durability and performance,
and it would be okay to do if they consent—but this was done without permission.
They probably thought, "You don't need expensive ceramic bearings;
with these bearings you can get lighter rotation more cheaply"—what idiots.
The left-side hub body bearing showed no water intrusion or rust,
so water damage wasn't the cause,
but the fact is the rotation failed in extremely short time
on sunny days only, under 2000 km.
The bearings are both NTN,
the metal-seal version is 6902Z,
and the non-contact rubber seal version is 6902LB.
Depending on the manufacturer,
Z or ZZ indicates metal seals, LB or LLB indicates non-contact rubber seals,
and LU or LLU indicates contact rubber seals.
With contact rubber seals, there's an incomplete rule
to make the seal color orange or brown,
and NTN does make them orange.
↑You can see the 6902LU has ridges where it contacts the inner race.
This time I replaced all with non-contact rubber seal bearings.
Metal seals are also non-contact, but
within the non-contact category,
the water resistance of Z is inferior to LB.
The hub shaft passing through the left hub body bearing
serves as a guide for driving straight,
so I attached the special tool
and seated the bearing.
It protrudes slightly from the back face of the hub body,
which is the normal state.
↑This is the face of the star ratchet spline toward the hub body,
and you need to seat a washer in the depression.
If you tighten the spline with this misaligned,
it'll be a disaster (not that I've done it).
The tightening tool tip has a step that matches the washer's inner diameter,
but as you tighten,
it doesn't automatically guide itself,
so you must confirm correct placement before firmly tightening.
This is the water-dust seal ring's face toward the hub body,
and the U-shaped groove side faces outward.
There's also a special tool for driving this straight in,
and this is how you seat it.
It's strange that in the original "overhaul" nonsense, they had the tool
but had no star ratchet special grease.
Well, I don't need to understand or bother trying to.
I returned it to front hub mode again.
Rotating the hub shaft by hand, it spins smoothly without cloudiness.
The freewheel body stop spacer touching the inner race of the right hub body bearing
shows wear marks that shouldn't appear in the short term.
Below this spacer are the star ratchet parts
set up like this,
but if the hub shaft has no play or runout,
such wear marks wouldn't appear in the short term.
The star ratchet parts were the lightened version.
With DT brand wheels, when you buy a fairly high-end wheel
or order just this part separately,
you get this version.
↑This has more ratchet teeth, an even higher grade,
so naturally it's lightened.
Budget hubs have the non-lightened version.
You can't buy this part individually.
In the lightened sections of the star ratchet parts,
the pink-colored star ratchet special grease
remains in its clean color even after extended use.
On this wheel, there was none of that,
and gray grease had seeped in.
DT has a multi-purpose grease (left in the image above) separate from the star ratchet special grease,
but this is different grease from both.
The freewheel body bearings were also swapped out for 6802Z.
There was nothing wrong internally or externally,
but after consulting with the customer, we decided to replace them anyway.
I removed the inner bearing and the spacer pressing the inner race.
The gray grease, mixed with contamination,
had become cotton-like,
and I extracted it with tweezers.
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