A customer dropped off a rear wheel built with a Shimano MT400 hub and
WTB rim for repair.
The parts needed for the repair didn't arrive for a while, so
I've had it for about 10 months.
The hub is FH-MT400-B, and since it has a "B" at the end,
it's a BOOST-spec hub.
The rim is WTB
ST i30, a 32-hole, 14-gauge plain two-cross laced rim.
The spoke head is stamped with a five-petal flower mark, indicating
spokes made by a Taiwanese manufacturer called "HT's" or "Hsing Ta Industrial,"
though they're more of a pedal maker than a spoke manufacturer.
Searching "HTI pedal" brings up pedals with the HT logo,
and searching "HTI spoke" shows spokes with an S-shaped stamp,
which are from the same manufacturer as the ones in the photo above.
These spokes are inexpensive, but they're actually harder to find domestically,
so this wheel might be an in-house build from a manufacturer like ENVE or SRM.
The chain dropped inside the sprocket, so the customer asked me to replace any spokes
that need it. Paint is chipped on all the drive-side spokes and some non-drive-side ones,
but few are severely frayed or clearly bent, so I ended up replacing just 3 spokes.
I used DT's black Champion spokes.
The nipples are long nipples without any particular practical reason,
but I'm just reusing them as-is.
There was Stans tubeless tape on it, but we don't stock this wide size.
We could order it, but unless we absolutely have to peel it off,
I'd rather not, so I worked around it.
Setting the spoke replacement aside, there's play in the freehub body.
The customer mentioned it might be related to chain-drop damage,
and while it's true the chain dropped and there is slight play in the freehub body,
I don't think there's a causal connection.
Shimano freehub bodies have ratchet pawls and loose ball bearings inside,
and since the balls aren't in a retainer, there's a slight gap relative to the ball race.
As grease works out over time, it starts making a rattling sound.
For more details on this and what's rarely seen inside an HG freehub body,
see here.
Separate from internal component noise, HG freehub bodies do have some necessary
eccentric play relative to the hub axle. Many people with older Shimano wheels have seen
the sprocket (with the freehub body attached) wobble eccentrically when spinning
the rear wheel in the air, like a spinning top that's off-center.
That eccentric play isn't zero from the start and can't be improved by adjustment or lubrication.
When the freehub body has significant play relative to the hub shell or axle,
possible causes include internal component wear, grease loss, or
loose tension on the hollow bolt that fixes the freehub body.
In this case, the latter is definitely not the issue, and since the part isn't that expensive,
we decided to replace the freehub body.
But the part that was supposed to arrive in about a month took 10 months to show up.
Speaking of which, that FC-6800 outer chainring the customer ordered on January 10, 2021
is now scheduled for August 24, 2022. It's been delayed over 15 times.
This customer is moving out of Japan by the end of March,
so they definitely won't get it. When it arrives, I'm planning to frame it
with a memo showing the order date and delivery date, so I'm not canceling.
This freehub body specifies a tightening torque of 150 N·m. If you think about it normally,
that's an absurd number. The highest torque specification I can think of offhand
for bicycle parts is 42 N·m for the left and right shaft bolts on a Campagnolo
Ultra-Torque crank.
So I decided to check if something like this could actually exist.
First, from Shimano's manual, the case of a quick-release spec hub.
The hollow bolt is turned with a 10mm Allen wrench,
and the specified torque is 35–50 N·m.
With a through-axle spec hub, the story changes:
The hollow bolt is turned with a 15mm Allen wrench. It makes sense it would be larger,
since a 12mm through-axle shaft passes through the hub axle.
The specified torque was, hard as it is to believe, actually 150 N·m.
Because it's not a torque you can tighten or loosen with a hand-turned L-shaped Allen wrench,
the instructions say to clamp the wrench in a vise and turn the wheel.
My torque wrench is a fairly pricey Tohnichi model,
but I can't go clamping it in a vise. I thought that instruction was only for loosening,
but the diagram shows "y" for the loosening direction and "z" for the tightening direction,
with both directions illustrated for the vise method, so apparently you're supposed to
tighten it this way too. When loosening, as long as it comes loose, I don't care
what the original torque was, but since tightening is specified,
this freehub body is actually harder to tighten "properly" than to remove.
I removed the hub axle. The bearing grease appeared to be Finish Line Teflon grease.
Also, it's missing a dust seal, though a new one comes with the replacement freehub body,
so that's not really an issue anymore.
A 15mm Allen wrench exists as an off-the-shelf product, but buying
Shimano's tool was the quickest route, and the price wasn't absurdly high,
so I went with that.
It broke free with a snap, so now I'm loosening it smoothly with the long end
of the L-shaped wrench. I ended up not using a vise to loosen it.
Strictly speaking, Shimano's recommended method didn't work for loosening at all.
This confirms what I mentioned earlier: the freehub body's play is definitely not due
to bolt loosening.
It's out. The bolt diameter is 24mm. The removed freehub body rattles when shaken,
and when I hold the spline section and bolt threads separately and apply force,
I can confirm it has more play than a new identical unit.
These are from before the axle removal, a provisional centering.
The rim is shifted toward the non-drive side, and there's some lateral runout too,
so there might be a phase where it centers perfectly in one spot. But overall,
the rim is definitely shifted toward the non-drive side.
After replacing the freehub body and 3 spokes, and correcting lateral runout
well, it had radial runout too but whatever with emphasis on the drive-side tension,
this is the state when the centering is considered good enough.
It's still off by about a sheet of paper toward the non-drive side. So close.
Centered.
Done.
↑Replaced spokes
WTB rim for repair.
The parts needed for the repair didn't arrive for a while, so
I've had it for about 10 months.
The hub is FH-MT400-B, and since it has a "B" at the end,
it's a BOOST-spec hub.
The rim is WTB
ST i30, a 32-hole, 14-gauge plain two-cross laced rim.
The spoke head is stamped with a five-petal flower mark, indicating
spokes made by a Taiwanese manufacturer called "HT's" or "Hsing Ta Industrial,"
though they're more of a pedal maker than a spoke manufacturer.
Searching "HTI pedal" brings up pedals with the HT logo,
and searching "HTI spoke" shows spokes with an S-shaped stamp,
which are from the same manufacturer as the ones in the photo above.
These spokes are inexpensive, but they're actually harder to find domestically,
so this wheel might be an in-house build from a manufacturer like ENVE or SRM.
The chain dropped inside the sprocket, so the customer asked me to replace any spokes
that need it. Paint is chipped on all the drive-side spokes and some non-drive-side ones,
but few are severely frayed or clearly bent, so I ended up replacing just 3 spokes.
I used DT's black Champion spokes.
The nipples are long nipples without any particular practical reason,
but I'm just reusing them as-is.
There was Stans tubeless tape on it, but we don't stock this wide size.
We could order it, but unless we absolutely have to peel it off,
I'd rather not, so I worked around it.
Setting the spoke replacement aside, there's play in the freehub body.
The customer mentioned it might be related to chain-drop damage,
and while it's true the chain dropped and there is slight play in the freehub body,
I don't think there's a causal connection.
Shimano freehub bodies have ratchet pawls and loose ball bearings inside,
and since the balls aren't in a retainer, there's a slight gap relative to the ball race.
As grease works out over time, it starts making a rattling sound.
For more details on this and what's rarely seen inside an HG freehub body,
see here.
Separate from internal component noise, HG freehub bodies do have some necessary
eccentric play relative to the hub axle. Many people with older Shimano wheels have seen
the sprocket (with the freehub body attached) wobble eccentrically when spinning
the rear wheel in the air, like a spinning top that's off-center.
That eccentric play isn't zero from the start and can't be improved by adjustment or lubrication.
When the freehub body has significant play relative to the hub shell or axle,
possible causes include internal component wear, grease loss, or
loose tension on the hollow bolt that fixes the freehub body.
In this case, the latter is definitely not the issue, and since the part isn't that expensive,
we decided to replace the freehub body.
But the part that was supposed to arrive in about a month took 10 months to show up.
Speaking of which, that FC-6800 outer chainring the customer ordered on January 10, 2021
is now scheduled for August 24, 2022. It's been delayed over 15 times.
This customer is moving out of Japan by the end of March,
so they definitely won't get it. When it arrives, I'm planning to frame it
with a memo showing the order date and delivery date, so I'm not canceling.
This freehub body specifies a tightening torque of 150 N·m. If you think about it normally,
that's an absurd number. The highest torque specification I can think of offhand
for bicycle parts is 42 N·m for the left and right shaft bolts on a Campagnolo
Ultra-Torque crank.
So I decided to check if something like this could actually exist.
First, from Shimano's manual, the case of a quick-release spec hub.
The hollow bolt is turned with a 10mm Allen wrench,
and the specified torque is 35–50 N·m.
With a through-axle spec hub, the story changes:
The hollow bolt is turned with a 15mm Allen wrench. It makes sense it would be larger,
since a 12mm through-axle shaft passes through the hub axle.
The specified torque was, hard as it is to believe, actually 150 N·m.
Because it's not a torque you can tighten or loosen with a hand-turned L-shaped Allen wrench,
the instructions say to clamp the wrench in a vise and turn the wheel.
My torque wrench is a fairly pricey Tohnichi model,
but I can't go clamping it in a vise. I thought that instruction was only for loosening,
but the diagram shows "y" for the loosening direction and "z" for the tightening direction,
with both directions illustrated for the vise method, so apparently you're supposed to
tighten it this way too. When loosening, as long as it comes loose, I don't care
what the original torque was, but since tightening is specified,
this freehub body is actually harder to tighten "properly" than to remove.
I removed the hub axle. The bearing grease appeared to be Finish Line Teflon grease.
Also, it's missing a dust seal, though a new one comes with the replacement freehub body,
so that's not really an issue anymore.
A 15mm Allen wrench exists as an off-the-shelf product, but buying
Shimano's tool was the quickest route, and the price wasn't absurdly high,
so I went with that.
It broke free with a snap, so now I'm loosening it smoothly with the long end
of the L-shaped wrench. I ended up not using a vise to loosen it.
Strictly speaking, Shimano's recommended method didn't work for loosening at all.
This confirms what I mentioned earlier: the freehub body's play is definitely not due
to bolt loosening.
It's out. The bolt diameter is 24mm. The removed freehub body rattles when shaken,
and when I hold the spline section and bolt threads separately and apply force,
I can confirm it has more play than a new identical unit.
These are from before the axle removal, a provisional centering.
The rim is shifted toward the non-drive side, and there's some lateral runout too,
so there might be a phase where it centers perfectly in one spot. But overall,
the rim is definitely shifted toward the non-drive side.
After replacing the freehub body and 3 spokes, and correcting lateral runout
this is the state when the centering is considered good enough.
It's still off by about a sheet of paper toward the non-drive side. So close.
Centered.
Done.
↑Replaced spokes