In the draft of my previous article
I had written down 3 things that bothered me
about the FH-TC500
but it got long, so I made it a separate post.
First, regarding the fact that there are
5 different variations in the model numbers at the end of the FH-TC500.
HM is a hub with an 11-speed HG freewheel body for MTB,
or in road bike terms,
a 10-speed HG freewheel body hub, and
limited to MTB 11-speed sprockets or 11-34T,
11-speed sprockets can be mounted. The speed designation
at Shimano is
M11/10/9/8.
HL is a road-use 11-speed HG freewheel body
and also supports 12-speed sprockets.
The freewheel body spline is
1.85mm longer than the HM, so
when using 11-34T 11-speed sprockets or
10~8-speed sprockets,
a 1.85mm spacer needs to be installed.
The speed designation at Shimano is 12/11-speed.
MS is a Microspline specification.
HM-B and MS-B are
respectively BOOST specifications of HM and MS, so
the rear hub end width is not 142mm
but 148mm.
HL does not have a BOOST specification.
There are 3 things that bother me about these.
The first is the road rim brake rear hubs
FH-RS300 and RS400
(nominally graded Sora and Tiagra)
each have freewheel bodies of
10-speed (11-speed possible with MTB and 11-34T) and
11-speed (12-speed also possible), and
these flange widths are respectively
57.9mm and 56.9mm.
Rather than the exact 1.85mm difference in freewheel body spline length,
there's a 1mm difference, but
"if a 10-speed freewheel body as used in road bikes is fine,
the RS300 is dimensionally superior."
In contrast, with the TC500 rear hub,
the flange width of HM, HL, and further MS are
all 55.45mm, and
"HM having a shorter freewheel body than HL's
dimensional superiority"
doesn't exist.
So I don't understand the meaning of setting up
an HM specification.
By the way, the flange width of HM-B and MS-B is
both 61.45mm, and
this is a dimension that puts all the
plus 6mm width from BOOSTification
entirely into the flange width.
The second is that as a
road 11-speed (also compatible with 12-speed)
disc road hub,
there are hubs called RS770 and RS470,
off-grade hubs, and
the front hubs of these RS770 and RS470 have
almost no weight difference.
There's barely any weight-related difference other than
the material of the end nuts.
When this becomes a rear hub, the hub shaft material is
aluminum or steel, so
RS470 is noticeably and considerably heavier
compared to RS770.
The TC500 front hub
even when held as a hub alone
doesn't feel particularly heavy, and
even verbatim from Shimano's site
"This sturdy and lightweight front hub is
designed for reliable road rides and
smooth gravel rides, and
is ideal for use with a
12mm E-thru axle."
they specifically mention lightness.
However, with the rear hub, only HL has
an introduction at the beginning about the hub's features, and
quoting the original:
"While considering ease of maintenance,
the versatile and reliable
12/11-speed freewheel hub features
reliability and combines e-bike, trekking, city riding and
matches all kinds of rides."
and that's all—if they said it was light
it would be a lie, so they don't mention it.
The third is, with the Microspline specification MS,
is there even a need to put out
a non-BOOST 142mm width rear hub?
Whether the next Dura-Ace (R9300 series)
will be Microspline specification or not, and
whether it will become 13-speed or not, I don't know, but
it's hard to imagine Shimano BOOSTifying road bike frames at that point.
The TC500 is a CUES-grade hub, but
if 142mm width road components
should become Microspline in the future,
it might have been set up as a hub for
hand-built wheels.
If that's the case, then all the more so,
why not put out a 24H specification?
And if that happens, I imagine
third-party 142mm width MS freehubs like Tni
will come out.
There are rumors that a wheel with carbon spokes
based on the WH-R9270
will be released at the WH-R9300 grade
ahead of the component groupset, but
in that case, the freewheel body should be
the current 12-speed-only HG.
Campagnolo announced the original Shamal
when they had 8-speed components, but
the following year (two years later in catalog year, but
roughly one year in practice) when the component became 9-speed,
they later released a freewheel body
that could be swapped from 8-speed to 9-speed
so that the rear wheel with the 8-speed freewheel body and Shamal
wouldn't be wasted.
Similarly, if the WH-R9370 is released
for use with the current R9200 series and
the R9300 series becomes Microspline freewheel body,
surely they won't completely ignore
the innovators and early adopters
who jumped on the WH-R9370 right away, but...
Those are the 3 things that bothered me,
but I'll continue further.
The FH-TC500 is
a CUES-grade
off-grade rear hub, and
on the Shimano maker site,
selecting the hub item under
Road/MTB/Gravel/Lifestyle categories →
Lifestyle → Components →
Drivetrain → Hub
is the only way to find it—
it's an extremely hard-to-find product.
Aside from TC500, the TC series hubs include
TC600.
Whether this rear hub, like the
RS770 and RS470 rear hub weight difference I mentioned earlier,
has no sense of heaviness to the TC600... that is,
whether it's light enough, I don't know.
However, regardless of weight, the FH-TC600
is currently a rear hub unrelated to disc road.
The reason is that the model number suffix
only exists in HM-B and MS-B variants—that is, BOOST specifications only.
The spoke hole count deployed in TC500 and TC600 rear hubs is
only the HL of FH-TC500 comes in 28/32H, and
other than that, the
HM, HM-B, MS, MS-B of TC-500 and
HM-B, MS-B of FH-TC600
also come in 36H.
So when doing a 36H spoke-skipped lacing on a
24H disc road rim,
there's no choice but to use
FH-TC500-HM. ← doesn't really matter
FH-TC500 and TC600 are not
Shimano's traditional-style freewheel hubs
(where the entire hub's right lockring is at the freewheel body right end,
cup-and-cone type) but instead
use a ratchet with coil springs and
cartridge bearing specification.
Looking at their exploded diagrams...
First, the TC600.
The left and right hub bearings have the same part number, but
the dimensions of this are 17×30×7 as stated
(outside the image range), and
17×30×7 refers to standard size 6903.
The ratchet pawls are on the freewheel body side,
the ratchet teeth are on the hub body side.
The reason I'm bothering to write such a thing is
because with the TC500, this is reversed.
So TC500 and TC600
don't have freewheel body compatibility.
Furthermore, the left hub body bearing has
dimensions of 15×28×7, so
this refers to standard size 6902, but
in contrast, the right hub body bearing is
supplied as a "bearing-equipped inner unit," and
there's no individual bearing sale, and
the dimensions are undisclosed (seems like 6903 though).
This is a part with ratchet pawls attached, with
a bearing press-fitted from inside to outside of the hub,
and the specified torque is 180–200 Nm.
Shimano has in the past specified
hollow bolt tightening torque securing the freewheel body
at a maximum of 200 Nm for
several hubs.
The factory assembly uses
a dedicated jig for this, presumably, but
to loosen a bolt tightened at 200 Nm
there's no way to do it with the hub alone,
and the freewheel body swap for that type
first requires securing an Allen key
like 14mm or 15mm
(sizes aren't even standardized, and
this tool is only for this job)
L-shaped with the short side facing up in a vise,
and the hub itself, with the wheel assembled,
you're supposed to grip the rim while rotating the wheel to
install or remove it—this is the official instruction.
The right bearing unit of FH-TC500 also
supports the same installation/removal method, but
the Allen key used is surprisingly 19mm.
The "bearing press-fitted from inside the ratchet tooth unit
screwed into the hub body" style
also exists with DT's Ratchet EXP
rear hub (image above), but
the ratchet part has a specialized tool
spline on the inside, and
it's easy to lengthen the wrench handle with the tool attached, and
since the bearing size is 15×26×7 with a relatively
small outer diameter, installation/removal of this
isn't a difficult job.
The RS300 and RS400 hubs
I mentioned as an example in
the first of the 3 concerning things, but
these front hubs—I can't figure out
what the performance differences are.
Only the RS400 comes in a silver hub barrel specification, but
with black on both sides, the SHIMANO markings are exactly the same, and
the included quick-release is also the same.
So I think these should be
unified to one (preferably the higher grade)
Campagnolo, after the Super Record came out,
the mechanical ergopower of Record and Chorus
have had all parts except brake lever parts (Record or Chorus marking)
be exactly the same.
So there's no difference in shift performance, feel, or weight.
Yet there's quite a price difference.
It's like paying money for the "prestige of using Record,"
but that said, when building up a groupset with Record,
it's rare to find someone saying
"it's actually the same as Record,
so I just used Chorus levers!"—
that's the terrifying thing about Campagnolo.
By the way, if you buy Chorus ergopower levers first and
then buy and retrofit Record brake lever parts,
it'll be more expensive than buying
genuine Record ergopower.
Changing the subject a bit,
Crank Brothers' pedaling cleats are
"odd-numbered grades
(though a 2 came out later), with 11 being the highest,"
but with Eggbeaters, the numbers jump drastically: 11, 3, 2, 1.
This is because in the old days when grades weren't numbers,
there were 3 types of Eggbeater titanium part specs
depending on how much was titaniumized,
and each was sold as Single Titanium, Double Titanium, and
Triple Titanium respectively.
The current 11 conforms to the former Triple Titanium spec.
And back then, aftermarket parts were sold
to upgrade Single and Double Titanium to
Triple Titanium.
But looking at their prices closely,
the cheapest way to get Triple Titanium was
"buy Single Titanium and upgrade to Triple Titanium with aftermarket parts."
Oh, how to tie this back to the main topic—
although there's a TC600 rear hub, there currently
doesn't exist an HB-TC600
front hub.
Which means, just like with the RS400 and RS300 front hubs,
if you're going to put out front hubs where you can't tell what's different,
you might as well merge them.
Rather, I don't understand the necessity of
making separate designs for TC500 and TC600 rear hubs
when their internal structures are completely different.
Upon investigation, the current M9200 series XTR and
M8200 series XT and M7100 series SLX rear hubs
use the same large-diameter coil spring method as the WH-R9270,
with two springs, and
the current M6100 series Deore
has no hub specification,
and the previous M6000 series
uses Shimano's traditional style, so
something like "TC600 is copied from XT style,
TC500 is copied from Deore style"
doesn't even hold water here.
The TC500 and TC600 rear hubs, while
the hub body shape is different, so
the dimensions of parts relating to wheel performance also differ.
Since TC600 only has BOOST hubs,
I'll compare with TC500's BOOST hub:
FH-TC500-( )-B flange width is
61.45mm.
In contrast, FH-TC600-( )-B's
61.1mm.
Looking at just this, TC500 seems superior, but
checking the left and right flange widths,
TC500's offset is 7.6mm,
TC600's offset is 7.19mm.
Smaller offset = less dishing
and left/right flange width is
"flange width/2 ± offset," so
calculating (or rather Shimano should publish the calculation results):
TC500 is
left flange width of 61.45/2+7.6 = 38.325mm,
right flange width of 61.45/2−7.6 = 23.125mm.
TC600 is
left flange width of 61.1/2+7.19 = 37.74mm,
right flange width of 61.1/2−7.19 = 23.36mm.
Flange width evaluation is completely different left and right;
a 1mm difference in left flange width is
barely noticeable even when building wheels, but
a 1mm difference in right flange width, especially on the narrower side,
you clearly feel the freewheel-side tension
immediately tighten more compared to the non-freewheel side.
From here, "TC600 has a narrower total
left and right flange width combined,
but with wider right flange width, is actually superior"
would be the conclusion, so I investigated,
but a 0.2mm right flange width difference
doesn't seem sufficient to overcome
the ~0.6mm wider left flange width
lateral stiffness merit when considering the magnitude of factors,
so they're about equivalent.
TC600 being a large flange is
likely to make for a better-engaging rear wheel.
Shimano traditionally (not all) often makes
the spoke hole PCD difference on rear hubs
1mm in diameter.
This is not with the flange part diameter of the hub body being the same
and drilling positioned inward only on the left side... rather,
the flange part diameter as a hub body dimension itself is also
1mm different.
Rim brake rear hubs typically have
left and right spoke hole PCD of 44/45mm, and
with TC500 rear hubs, this is
spoke hole PCD of 50.5/51.5mm,
flange itself diameter of 59.3/60.3mm,
with TC600 rear hubs,
spoke hole PCD of 60/61mm,
flange itself diameter of 68.8/69.8mm.
The flange's own diameter is
not necessary information for building wheels, so
when other hub manufacturers/brands
publish dimensions, it's usually
not even written, but
Shimano calls what I call
spoke hole PCD (or in most cases flange diameter) "P.C.D.,"
and the flange's own diameter "flange diameter," so
if you plug Shimano's "flange diameter" into the calculation formula,
you'll certainly get the spoke length wrong, so be careful.
"While bathing,
washing your head with shampoo
and installing a Hollowtech II BB"
is a situation Shimano apparently assumes, and
similarly, "placing a truing stand on top of a wide slide or
in the middle of a steep slope
to build the rear wheel"
is also apparently assumed.
If you accidentally roll a rear hub down a slope while trying to build a wheel,
if the left and right flanges had the same diameter,
it would roll forever, but
because the left and right flanges are slightly different diameters,
the hub, while rolling, spins around and changes direction, so
it hits something or stops, making it
easier to retrieve—this seems to be the intent.
The spline on the Hollowtech II threaded hole BB small parts
outer cup comes in the large diameter from the initial release and
the small diameter that came later for SM-BB9000,
plus a slightly smaller diameter that came after, which is hard to tell apart,
from the initial one, with
3 types, and the specialized tools for assembly also
are all different sizes.
The image above shows the initial one on the left and
the SM-BBR60-use one on the right, but
even in a situation where shampoo stings your eyes so they're closed,
to avoid accidentally choosing the wrong one
only the BBR-60 type has
the same tactile bumps (ridges) as on
shampoo pump heads or
the side of the bottle.
The smooth, smooth-feeling one is
the initial-size tool or rinse,
rinse-in shampoo, in which case
it falls under the definition of shampoo,
and the bumpy one, so if you remember
with-ridges-yes,
even with eyes closed you can avoid
wasting shampoo and tool mix-ups.
For BSC BBs where the right cup is
reverse-threaded, how do you even tell the difference?! people might ask—
I'd recommend getting a
shampoo hat, but
people like that should just give up on trying to
assemble BBs in the bath altogether.
For some reason Shimano
stubbornly refuses to make a
20H front hub for nipple-less spokes.
If you disassemble the front wheel of WH-R500/501,
you can get something equivalent,
but single units aren't sold.
Even Shimano's most spoke-count-diverse
7700 series Dura-Ace hubs come in
12, 16, 24, 28, 32, and 36H, and
with even 18H for the front only as well, and
yet with 12H hubs even being made,
not making 20H hubs
makes absolutely no sense.
If Dura-Ace, Ultegra, and 105 had
20H front hubs, they'd have been used
by the hundreds instead of Tni
for things like the Noma-Lab wheels.
Shimano continues, even now, with this sort of
outmoded, nonsensical spoke-count lineup in a way like
"we make 36H disc hubs,
but not 24H"—
stubbornly maintaining such practices.
The price difference between
TC500 and TC600 rear hubs is
nearly 2000 yen (※1), so
drop the poorly-maintained TC500's unique spec
(the spare parts holding period for the right bearing unit
will be quite short after product discontinuation, presumably)
and unify the rear hubs in TC600 spec, and
if you'd release 142mm width with HL freewheel body (12-speed) and
24H spec,
it could become a god hub, but
never scratching that itch
is what's "Shimano-like" about the
TC500/600 hubs.
※1 I understand that a 2000-yen price difference
is an absolutely huge factor in the judgment of
whether OEM manufacturers assemble them in complete bikes
※2 They're famous for continuing to release
"itchy" parts like sprocket tooth configurations
that draw complaints from laypeople
I had written down 3 things that bothered me
about the FH-TC500
but it got long, so I made it a separate post.
First, regarding the fact that there are
5 different variations in the model numbers at the end of the FH-TC500.
HM is a hub with an 11-speed HG freewheel body for MTB,
or in road bike terms,
a 10-speed HG freewheel body hub, and
limited to MTB 11-speed sprockets or 11-34T,
11-speed sprockets can be mounted. The speed designation
at Shimano is
M11/10/9/8.
HL is a road-use 11-speed HG freewheel body
and also supports 12-speed sprockets.
The freewheel body spline is
1.85mm longer than the HM, so
when using 11-34T 11-speed sprockets or
10~8-speed sprockets,
a 1.85mm spacer needs to be installed.
The speed designation at Shimano is 12/11-speed.
MS is a Microspline specification.
HM-B and MS-B are
respectively BOOST specifications of HM and MS, so
the rear hub end width is not 142mm
but 148mm.
HL does not have a BOOST specification.
There are 3 things that bother me about these.
The first is the road rim brake rear hubs
FH-RS300 and RS400
(nominally graded Sora and Tiagra)
each have freewheel bodies of
10-speed (11-speed possible with MTB and 11-34T) and
11-speed (12-speed also possible), and
these flange widths are respectively
57.9mm and 56.9mm.
Rather than the exact 1.85mm difference in freewheel body spline length,
there's a 1mm difference, but
"if a 10-speed freewheel body as used in road bikes is fine,
the RS300 is dimensionally superior."
In contrast, with the TC500 rear hub,
the flange width of HM, HL, and further MS are
all 55.45mm, and
"HM having a shorter freewheel body than HL's
dimensional superiority"
doesn't exist.
So I don't understand the meaning of setting up
an HM specification.
By the way, the flange width of HM-B and MS-B is
both 61.45mm, and
this is a dimension that puts all the
plus 6mm width from BOOSTification
entirely into the flange width.
The second is that as a
road 11-speed (also compatible with 12-speed)
disc road hub,
there are hubs called RS770 and RS470,
off-grade hubs, and
the front hubs of these RS770 and RS470 have
almost no weight difference.
There's barely any weight-related difference other than
the material of the end nuts.
When this becomes a rear hub, the hub shaft material is
aluminum or steel, so
RS470 is noticeably and considerably heavier
compared to RS770.
The TC500 front hub
even when held as a hub alone
doesn't feel particularly heavy, and
even verbatim from Shimano's site
"This sturdy and lightweight front hub is
designed for reliable road rides and
smooth gravel rides, and
is ideal for use with a
12mm E-thru axle."
they specifically mention lightness.
However, with the rear hub, only HL has
an introduction at the beginning about the hub's features, and
quoting the original:
"While considering ease of maintenance,
the versatile and reliable
12/11-speed freewheel hub features
reliability and combines e-bike, trekking, city riding and
matches all kinds of rides."
and that's all—if they said it was light
it would be a lie, so they don't mention it.
The third is, with the Microspline specification MS,
is there even a need to put out
a non-BOOST 142mm width rear hub?
Whether the next Dura-Ace (R9300 series)
will be Microspline specification or not, and
whether it will become 13-speed or not, I don't know, but
it's hard to imagine Shimano BOOSTifying road bike frames at that point.
The TC500 is a CUES-grade hub, but
if 142mm width road components
should become Microspline in the future,
it might have been set up as a hub for
hand-built wheels.
If that's the case, then all the more so,
why not put out a 24H specification?
And if that happens, I imagine
third-party 142mm width MS freehubs like Tni
will come out.
There are rumors that a wheel with carbon spokes
based on the WH-R9270
will be released at the WH-R9300 grade
ahead of the component groupset, but
in that case, the freewheel body should be
the current 12-speed-only HG.
Campagnolo announced the original Shamal
when they had 8-speed components, but
the following year (two years later in catalog year, but
roughly one year in practice) when the component became 9-speed,
they later released a freewheel body
that could be swapped from 8-speed to 9-speed
so that the rear wheel with the 8-speed freewheel body and Shamal
wouldn't be wasted.
Similarly, if the WH-R9370 is released
for use with the current R9200 series and
the R9300 series becomes Microspline freewheel body,
surely they won't completely ignore
the innovators and early adopters
who jumped on the WH-R9370 right away, but...
Those are the 3 things that bothered me,
but I'll continue further.
The FH-TC500 is
a CUES-grade
off-grade rear hub, and
on the Shimano maker site,
selecting the hub item under
Road/MTB/Gravel/Lifestyle categories →
Lifestyle → Components →
Drivetrain → Hub
is the only way to find it—
it's an extremely hard-to-find product.
Aside from TC500, the TC series hubs include
TC600.
Whether this rear hub, like the
RS770 and RS470 rear hub weight difference I mentioned earlier,
has no sense of heaviness to the TC600... that is,
whether it's light enough, I don't know.
However, regardless of weight, the FH-TC600
is currently a rear hub unrelated to disc road.
The reason is that the model number suffix
only exists in HM-B and MS-B variants—that is, BOOST specifications only.
The spoke hole count deployed in TC500 and TC600 rear hubs is
only the HL of FH-TC500 comes in 28/32H, and
other than that, the
HM, HM-B, MS, MS-B of TC-500 and
HM-B, MS-B of FH-TC600
also come in 36H.
24H disc road rim,
there's no choice but to use
FH-TC500-HM. ← doesn't really matter
FH-TC500 and TC600 are not
Shimano's traditional-style freewheel hubs
(where the entire hub's right lockring is at the freewheel body right end,
cup-and-cone type) but instead
use a ratchet with coil springs and
cartridge bearing specification.
Looking at their exploded diagrams...
First, the TC600.
The left and right hub bearings have the same part number, but
the dimensions of this are 17×30×7 as stated
(outside the image range), and
17×30×7 refers to standard size 6903.
The ratchet pawls are on the freewheel body side,
the ratchet teeth are on the hub body side.
The reason I'm bothering to write such a thing is
because with the TC500, this is reversed.
So TC500 and TC600
don't have freewheel body compatibility.
Furthermore, the left hub body bearing has
dimensions of 15×28×7, so
this refers to standard size 6902, but
in contrast, the right hub body bearing is
supplied as a "bearing-equipped inner unit," and
there's no individual bearing sale, and
the dimensions are undisclosed (seems like 6903 though).
This is a part with ratchet pawls attached, with
a bearing press-fitted from inside to outside of the hub,
and the specified torque is 180–200 Nm.
Shimano has in the past specified
hollow bolt tightening torque securing the freewheel body
at a maximum of 200 Nm for
several hubs.
The factory assembly uses
a dedicated jig for this, presumably, but
to loosen a bolt tightened at 200 Nm
there's no way to do it with the hub alone,
and the freewheel body swap for that type
first requires securing an Allen key
like 14mm or 15mm
(sizes aren't even standardized, and
this tool is only for this job)
L-shaped with the short side facing up in a vise,
and the hub itself, with the wheel assembled,
you're supposed to grip the rim while rotating the wheel to
install or remove it—this is the official instruction.
The right bearing unit of FH-TC500 also
supports the same installation/removal method, but
the Allen key used is surprisingly 19mm.
The "bearing press-fitted from inside the ratchet tooth unit
screwed into the hub body" style
also exists with DT's Ratchet EXP
rear hub (image above), but
the ratchet part has a specialized tool
spline on the inside, and
it's easy to lengthen the wrench handle with the tool attached, and
since the bearing size is 15×26×7 with a relatively
small outer diameter, installation/removal of this
isn't a difficult job.
The RS300 and RS400 hubs
I mentioned as an example in
the first of the 3 concerning things, but
these front hubs—I can't figure out
what the performance differences are.
Only the RS400 comes in a silver hub barrel specification, but
with black on both sides, the SHIMANO markings are exactly the same, and
the included quick-release is also the same.
So I think these should be
unified to one (preferably the higher grade)
Campagnolo, after the Super Record came out,
the mechanical ergopower of Record and Chorus
have had all parts except brake lever parts (Record or Chorus marking)
be exactly the same.
So there's no difference in shift performance, feel, or weight.
Yet there's quite a price difference.
It's like paying money for the "prestige of using Record,"
but that said, when building up a groupset with Record,
it's rare to find someone saying
"it's actually the same as Record,
so I just used Chorus levers!"—
that's the terrifying thing about Campagnolo.
By the way, if you buy Chorus ergopower levers first and
then buy and retrofit Record brake lever parts,
it'll be more expensive than buying
genuine Record ergopower.
Changing the subject a bit,
Crank Brothers' pedaling cleats are
"odd-numbered grades
(though a 2 came out later), with 11 being the highest,"
but with Eggbeaters, the numbers jump drastically: 11, 3, 2, 1.
This is because in the old days when grades weren't numbers,
there were 3 types of Eggbeater titanium part specs
depending on how much was titaniumized,
and each was sold as Single Titanium, Double Titanium, and
Triple Titanium respectively.
The current 11 conforms to the former Triple Titanium spec.
And back then, aftermarket parts were sold
to upgrade Single and Double Titanium to
Triple Titanium.
But looking at their prices closely,
the cheapest way to get Triple Titanium was
"buy Single Titanium and upgrade to Triple Titanium with aftermarket parts."
Oh, how to tie this back to the main topic—
although there's a TC600 rear hub, there currently
doesn't exist an HB-TC600
front hub.
Which means, just like with the RS400 and RS300 front hubs,
if you're going to put out front hubs where you can't tell what's different,
you might as well merge them.
Rather, I don't understand the necessity of
making separate designs for TC500 and TC600 rear hubs
when their internal structures are completely different.
Upon investigation, the current M9200 series XTR and
M8200 series XT and M7100 series SLX rear hubs
use the same large-diameter coil spring method as the WH-R9270,
with two springs, and
the current M6100 series Deore
has no hub specification,
and the previous M6000 series
uses Shimano's traditional style, so
something like "TC600 is copied from XT style,
TC500 is copied from Deore style"
doesn't even hold water here.
The TC500 and TC600 rear hubs, while
the hub body shape is different, so
the dimensions of parts relating to wheel performance also differ.
Since TC600 only has BOOST hubs,
I'll compare with TC500's BOOST hub:
FH-TC500-( )-B flange width is
61.45mm.
In contrast, FH-TC600-( )-B's
61.1mm.
Looking at just this, TC500 seems superior, but
checking the left and right flange widths,
TC500's offset is 7.6mm,
TC600's offset is 7.19mm.
Smaller offset = less dishing
and left/right flange width is
"flange width/2 ± offset," so
calculating (or rather Shimano should publish the calculation results):
TC500 is
left flange width of 61.45/2+7.6 = 38.325mm,
right flange width of 61.45/2−7.6 = 23.125mm.
TC600 is
left flange width of 61.1/2+7.19 = 37.74mm,
right flange width of 61.1/2−7.19 = 23.36mm.
Flange width evaluation is completely different left and right;
a 1mm difference in left flange width is
barely noticeable even when building wheels, but
a 1mm difference in right flange width, especially on the narrower side,
you clearly feel the freewheel-side tension
immediately tighten more compared to the non-freewheel side.
From here, "TC600 has a narrower total
left and right flange width combined,
but with wider right flange width, is actually superior"
would be the conclusion, so I investigated,
but a 0.2mm right flange width difference
doesn't seem sufficient to overcome
the ~0.6mm wider left flange width
lateral stiffness merit when considering the magnitude of factors,
so they're about equivalent.
TC600 being a large flange is
likely to make for a better-engaging rear wheel.
Shimano traditionally (not all) often makes
the spoke hole PCD difference on rear hubs
1mm in diameter.
This is not with the flange part diameter of the hub body being the same
and drilling positioned inward only on the left side... rather,
the flange part diameter as a hub body dimension itself is also
1mm different.
Rim brake rear hubs typically have
left and right spoke hole PCD of 44/45mm, and
with TC500 rear hubs, this is
spoke hole PCD of 50.5/51.5mm,
flange itself diameter of 59.3/60.3mm,
with TC600 rear hubs,
spoke hole PCD of 60/61mm,
flange itself diameter of 68.8/69.8mm.
The flange's own diameter is
not necessary information for building wheels, so
when other hub manufacturers/brands
publish dimensions, it's usually
not even written, but
Shimano calls what I call
spoke hole PCD (or in most cases flange diameter) "P.C.D.,"
and the flange's own diameter "flange diameter," so
if you plug Shimano's "flange diameter" into the calculation formula,
you'll certainly get the spoke length wrong, so be careful.
"While bathing,
washing your head with shampoo
and installing a Hollowtech II BB"
is a situation Shimano apparently assumes, and
similarly, "placing a truing stand on top of a wide slide or
in the middle of a steep slope
to build the rear wheel"
is also apparently assumed.
If you accidentally roll a rear hub down a slope while trying to build a wheel,
if the left and right flanges had the same diameter,
it would roll forever, but
because the left and right flanges are slightly different diameters,
the hub, while rolling, spins around and changes direction, so
it hits something or stops, making it
easier to retrieve—this seems to be the intent.
The spline on the Hollowtech II threaded hole BB small parts
outer cup comes in the large diameter from the initial release and
the small diameter that came later for SM-BB9000,
plus a slightly smaller diameter that came after, which is hard to tell apart,
from the initial one, with
3 types, and the specialized tools for assembly also
are all different sizes.
The image above shows the initial one on the left and
the SM-BBR60-use one on the right, but
even in a situation where shampoo stings your eyes so they're closed,
to avoid accidentally choosing the wrong one
only the BBR-60 type has
the same tactile bumps (ridges) as on
shampoo pump heads or
the side of the bottle.
The smooth, smooth-feeling one is
the initial-size tool or rinse,
rinse-in shampoo, in which case
it falls under the definition of shampoo,
and the bumpy one, so if you remember
with-ridges-yes,
even with eyes closed you can avoid
wasting shampoo and tool mix-ups.
For BSC BBs where the right cup is
reverse-threaded, how do you even tell the difference?! people might ask—
I'd recommend getting a
shampoo hat, but
people like that should just give up on trying to
assemble BBs in the bath altogether.
For some reason Shimano
stubbornly refuses to make a
20H front hub for nipple-less spokes.
If you disassemble the front wheel of WH-R500/501,
you can get something equivalent,
but single units aren't sold.
Even Shimano's most spoke-count-diverse
7700 series Dura-Ace hubs come in
12, 16, 24, 28, 32, and 36H, and
with even 18H for the front only as well, and
yet with 12H hubs even being made,
not making 20H hubs
makes absolutely no sense.
If Dura-Ace, Ultegra, and 105 had
20H front hubs, they'd have been used
by the hundreds instead of Tni
for things like the Noma-Lab wheels.
Shimano continues, even now, with this sort of
outmoded, nonsensical spoke-count lineup in a way like
"we make 36H disc hubs,
but not 24H"—
stubbornly maintaining such practices.
The price difference between
TC500 and TC600 rear hubs is
nearly 2000 yen (※1), so
drop the poorly-maintained TC500's unique spec
(the spare parts holding period for the right bearing unit
will be quite short after product discontinuation, presumably)
and unify the rear hubs in TC600 spec, and
if you'd release 142mm width with HL freewheel body (12-speed) and
24H spec,
it could become a god hub, but
never scratching that itch
is what's "Shimano-like" about the
TC500/600 hubs.
※1 I understand that a 2000-yen price difference
is an absolutely huge factor in the judgment of
whether OEM manufacturers assemble them in complete bikes
※2 They're famous for continuing to release
"itchy" parts like sprocket tooth configurations
that draw complaints from laypeople