During this morning's training ride, the IRC S-Light developed a slow puncture.
But first. This is an image from the day right after I rode on the tire that got the slow puncture today.
April 30th of this year.
Exactly two months ago.
The location is the intersection in Ohno town at the base of Nabeya Pass.
It was already raining when I left home,
so I wore a rain jacket—or rather a waterproof wind breaker on top,
and didn't mind my shoes getting wet, but wore waterproof socks on the bottom.
I switched my race bib shorts to regular shorts.
I applied Wako's sunscreen to the exposed knees and shins.
It acts as a water-repelling waterproof coating and
doesn't come off unless you use cleansing—
just scrubbing with soap won't get it off.
I tend to use Wako's sunscreen more often for this purpose than actual sun protection,
but to do this you need temperatures warm enough that rain doesn't chill your knees.
I judged this day was right at the borderline of such temperatures,
so I didn't wear full-length rain pants.
With water-repelling legs and shorts, there's no interference with pedaling.
I intend to write an article someday about POLAR's poorusability,
but the current VANTAGE V series
doesn't allow you to select "temperature" as a display item.
The previous V800 series, and even older RS and S series,
did allow you to select temperature as a display item.
It's not that they don't collect temperature data—
they record it in the background, so
when you download the ride data to a PC, you can view it afterward.
It's convenient to be able to see temperature in real time,
so you can confirm while riding things like "at this temperature I'll need thermal shoe covers"
or "what temperature was it when I took off my arm warmers?"
Those electronic display thermometers on the roadside
tend to show temperatures that are "conservative" compared to actual body sensation.
The temperature sensor is located away from the ground,
so it doesn't pick up ground heat reflection well, or
in summer the cycle computer shows higher temperatures,
and in winter it doesn't pick up the chill, so
the cycle computer tends to show lower temperatures.
This is especially pronounced when it's particularly hot.
Just now, when I checked the temperature recorded when the GPS trace was at Ohno town on April 30th,
it was 16.3°C.
At this temperature range it seems to be a zone where there's no upswing or downswing.
Today I had business at my mentor's place,
so I left home at 4 AM to be able to stop by around 8–9 AM.
Judging that going out of Osaka via Kazahuki Pass and back into Osaka via Kimi Pass
would work out well in terms of both time and route.
This is the Osaka-side entrance to Kazahuki Pass today.
It's called the "Osaka-side entrance,"
but you've already entered Wakayama Prefecture just before the tunnel,
so officially it's in Wakayama Prefecture.
By the way, the road station just before the tunnel is also in Wakayama Prefecture.
For some reason, I often see snails at this tunnel entrance.
I don't think they're the same individual, but I always see just one.
You can see it in the upper part of the image above,
In close-up, it looks like this.
It's producing feces so I don't think it's dead,
but the body is withdrawn into the shell and doesn't move.
This is from July 30th of last year.
I didn't take photos, but the next day
what appeared to be the same snail
had progressed about 10 meters into the tunnel,
and I was curious whether it would make it back alive.
This is from June 1st of this year.
I splashed water from my bottle on it.
No reaction.
I took a bit of a detour (about 200 meters round trip),
but this is the Great Gate of Kokawa Temple (Kokawa-dera).
↑My mental map of the area
Between Nabeya Pass and Kimi Pass there's Mt. Katsuragi,
but I almost never go there so I left it out.
Between Kazahuki Pass and Nabeya Pass there's Mt. Inunaki (Ikeda Tunnel),
which I climb sometimes, but I forgot to mark it.
Descending Kazahuki Pass, there's first a regional farm road, then below that the Kokawa-Kada Line,
and further down National Route 24,
but the Kokawa-Kada Line connecting Kada to Kokawa and merging with Route 24
has little traffic and few traffic lights, making it easy to ride.
If I rode the regional farm road I'd hit the Miyuki-tsuji South intersection at the base of Kimi Pass,
but the ups and downs are gnarly so I skip it.
After getting onto Route 24, I head east for a bit,
but soon I cross the Kino River to the south and ride to the base of Kimi Pass,
so I barely ride on Route 24.
↑It's like this, I just pass through it.
By the way, from Nabeya Pass you can ride up to Mt. Koya via National Route 480
(or rather, Nabeya Pass itself is Route 480), and
from Kimi Pass via National Route 371
(or rather, Kimi Pass itself is Route 371),
and they both converge at Yatate Teahouse, after which it's a single road.
So when I crossed the Kino River near Kokawa,
at a bridge joint that has a W-wave pattern,
there was a gap that was bigger than I expected, and carelessly I caused a rim strike.
I think it happened after that, but a fairly slow puncture
developed, and on the way back up Kimi Pass
I added air with a portable pump.
Just before that, there was a feeling of rim strike even at very small bumps.
From experience, when I notice a slow puncture and add air,
if I put in enough air that the internal pressure doesn't explode the sealant scab—
for example, about 4 bar—
the higher the pressure, the faster the air escapes, and
eventually it drops to about 2 bar, but
it often seems to stabilize at "an air pressure that barely leaks further."
But this time, the slow puncture went through that threshold and
leaked slowly but steadily on and on.
Separate from what I mentioned about adding air on Kimi Pass,
I also added air at the summit of Kimi Pass.
I pressurized it to the point where my finger wouldn't make a dent,
but I was still getting a feeling of rim strike on the descents of Kimi Pass at bumps.
↑This is the sealant scab.
I remembered it as "next to the round tire wear indicator near the valve,"
but since there are three valves it's hard to find.
This slow puncture wasn't caused by a scab burst, but rather
by a violent rim strike that partially compromised the tire bead seal.
That's my impression.
On the way back, I chose Kimi Pass because it's the closest pass to my mentor's workshop,
and I borrowed a floor pump there and gambled by putting in 5 bar,
at which point no scab burst occurred
(there was no "pop!" sound of the bead lifting either).
After chatting for about an hour, I headed out,
and when I checked before I left, the air hadn't leaked at all in that hour of sitting.
From there I passed in front of Brother Maintenance (→here)
and since Route 310 has a lot of traffic, I took an alternative back road one block in,
the Koya Kaido (which merges with Route 310 in Sakai),
and while riding that road, the scab burst three times,
spewing sealant with "pssh pssh pssh!" from the wound,
but as I kept riding it sealed itself back up and
just dropped to a lower pressure—and the sealant did its job in a few wheel rotations.
The air pressure when I got home was around 3 bar.
The slow puncture up to Kimi Pass
wasn't caused by a scab burst.
After the buckling of the bridge joint
there was an air leak with no lower limit, so to speak.
Probably even if there was no sealant scab at all, it would have happened.
On the way back from my mentor's place,
a scab burst occurred three times—something that didn't happen during the static hold at 5 bar—
but during that stretch I didn't feel any rim strike,
so it's almost certain that there was no continuous air leak
other than during the scab bursts.
The reason air was leaking before and after pumping with the floor pump
was different.
In the state where air was added at the summit of Kimi Pass,
the air would have continued to leak even at rest,
but after pumping with the floor pump,
the tire deformation from riding exceeded what it could handle,
and air only escaped if the scab couldn't hold—that's how it felt.
Then when I got home and looked at the bike,
sealant had splattered on the back of the seat tube.
The Cat Eye light in the leather case hanging from the saddle
also has sealant on it.
Since rain was forecast for that day, I put my wallet and phone in a waterproof pack
and carried a waterproof wind breaker in my back pocket,
but since it didn't rain during the time I rode, I didn't use them.
If I'd been riding in the rain, some of this sealant might have been washed off.
The puncture was on the right side, but sealant
had splattered even onto the back of the right crank's 4-arm.
It would be annoying if it dried completely,
so I scrubbed it off with a warm shower.
Unrelated to this, when you ride in summer and touch the underside of the top tube
and feel gritty from salt in your sweat,
if you can at least rinse it quickly with water,
or if that's difficult, wipe it with a damp cloth or paper towel,
making this a habit makes a significant difference
in the long-term damage accumulation to the frame.
The only frame you don't have to worry about this with is an unpainted titanium frame.
Even then, if the top tube's cable stop is blind-riveted rather than welded,
you should do it.
I've been told by customers multiple times,
"IRC's tubeless tires seem to puncture all the time."
I deliberately choose the S-Light knowing the puncture risk,
despite its being virtually unmatched in its lightness,
and since I ride pretty casually even in the rain
(I don't just get caught in rain, I ride even if it's already raining when I leave),
I'm not dissatisfied with the frequency of punctures.
The reason I say "virtually unmatched in its lightness" in the past tense
is because similar-weight tires are now available from other manufacturers,
and one of them, a certain Japanese brand that's not IRC,
has never made a decent road bike tire in the past—at least as far as I know—
and I've been burned by them many times,
so I'm leaving the role of being burned to other people.
If they ever made a decent tire, you'd hear such feedback.
Until then, I'm sitting this one out.
If I list a few examples of actual stories I've heard,
there's "the lightness you feel in your hands doesn't translate to rolling lightness,"
"it punctures immediately,"
"they supplied me with a tubular version, and it's a shit tire,"
"they said they'd give me one free if I wrote a report,
so I use it, but I wouldn't buy it to use,"
"(when I tried to refit the tire I'd removed for inspection)
I'm going back to Grand Prix 5000, so no tire needed,"
and similar things.
Also, I talked on the phone once with someone at a certain wholesale company
who is in some sense my senior in the bike business,
and the subject of that tire came up, and
he expressed surprise: "If you just do proper SNS advertising,
repeat customers aside, in the early stages it sells like that much?"r/>This senior was also a former pro rider,
so there was a time when he strictly upheld the pro job
of eating deliciously on camera, no matter what he truly thought
of what sponsors gave him,
and he may have had experience appearing to enjoy eating that brand's tire (so to speak).
Anyway, the tire that developed the slow puncture this time
has pretty worn tread, so
I decided to replace it, but I hadn't bought backup stock.
In such cases, as a makeshift measure, I'd normally
patch the back of the tire and use it until the same tire arrives,
but this time I decided to try
a Continental Grand Prix 5000S TR from the shop's inventory instead.
The actual measured weight for 25C is
just under 260g
(and as you can see in the image above,
I removed the 7-8g instruction sheet).
The 5000 TL, which was tubeless rather than tubeless ready,
was discontinued when the 5000S TR came out.
I've never used it (and never stocked it),
and at 300g measured weight in the narrowest 25C width,
I figured even if rolling was light, I didn't want it,
but from people who actually used it,
the feedback was mostly that compared to the tubed 5000,
before you could even feel the tubeless-specific ride quality,
the ride was abnormally sluggish and useless.
Also, the tire sidewall is thick and the bead is stiff,
so depending on the rim's internal width,
it's far harder to mount than a same-width tubed 5000,
and Mavic explicitly states that the only tubeless tire that fits Road UST tubeless rims
is Road UST tubeless tires, so while Mavic isn't wrong,
fitting it to a Mavic rim is extremely difficult,
and if you force it on, removing it in the field becomes
practically impossible for an ordinary person.
It's like equipping a cursed item in Dragon Quest.
You can only get it removed at the church.
While I've never stocked it,
I've handled it enough in inspections and such that
when I learned it was discontinued, I speculated there must have been
some awkward circumstances beyond the tire's performance.
With the 5000S TR, the tire bead is
considerably bulkier compared to the IRC.
There were no deformations like dents,
but there was a scrape on the rim side from the bridge joint buckling.
This definitely wasn't there until yesterday.
I really messed up there.
The bead protrusion is large.
People who started road cycling in the last couple of years
and have never ridden a rim-brake road bike
might not know, but before Grand Prix 5000,
there was a tire called Grand Prix 4000, and
it went through 4000 → 4000S → 4000S II as minor updates,
but with all of these models, at
the end of the casing just outside the tire-rim boundary,
threads would fray and stick out as a result of aging and use
(→here).
The 5000 TL came after 5000, but
for some reason the manufacturing was the same as the 4000,
and those threads that didn't appear on 5000
appeared on 5000 TL again.
I'm curious how this is on the 5000S TR.
Since the side is covered with rubber,
I suspect the threads won't appear, but.
With the IRC S-Light in 23C or 25C,
on the rims I use,
I've found from experience that I can mount and remove the tire without a tire lever.
I've confirmed that even with the tire mounted and bead seated to full pressure,
in its almost-new, unridden state, I can remove it without a lever.
So the portable tire lever I carry
is just one small one as insurance.
That's the IRC tire lever shortened
or the PB (famous for hex keys) tire lever in the image above.
In terms of pure tire lever performance, it's shorter even compared to the
Malni and Campagnolo (Fulcrum) ones above,
and since it has no curve, it's excellent for portability.
What concerned me was whether with the Grand Prix 5000S TR
I'd need to carry additional tire levers.
First, fitting: fitting the first bead to the rim required a tire lever.
Fitting the second bead was doable with hands only,
and surprisingly, the final part of seating the bead
was softer than the bead's thick appearance would suggest.
Getting the bead to seat via compressor
was quite smooth, and clearly easier than the IRC.
Incidentally, the IRC becomes pretty hard to get the bead up
if you use older, aged tires.
Most tire brands have that tendency,
but the IRC is especially pronounced.
Next, removing the tire from that state—
removing the first bead was doable by hand.
What surprised me was that the second bead also came off easily by hand.
Although fitting required a tire lever.
It seems unlikely that a single pressurization would have made the tire sidewall stretch that much,
so maybe I picked up some technique.
I think I can stick with just carrying one portable tire lever.
Fitted again.
Doable without a tire lever.
Second time I'madding Moji sealant.
Even though the tire width is 25C, I'm testing whether 35ml is sufficient.
↑This is the Grand Prix 4000 (on Racing Zero), but
the beginning of thread fraying and casing exposure look like this.
With the Grand Prix 5000S TR, given the way it's covered,
I suspect threads won't come out.
The sprocket is a Tni (Tني) chromoly 11-speed one (→here).
The supply of Shimano sprockets I was using before
wasn't stable
(↑that's written as if it's resolved now),
so I tried this, but after getting a 105 11-30T,
I went through a period of not using it.
This sprocket's shift performance is naturally inferior to genuine Shimano,
but it's not unusable,
but it seems that it doesn't fit the inner link width of Shimano 11-speed chains,
and the chain doesn't fully seat in the tooth valley,
so rarely, under hard acceleration or climbing torque
the chain slips forward.
I followed the sprocket's instruction to "start with a new chain,"
so chain wear isn't the cause.
That problem is now solved,
and I'm using a Campagnolo 12-speed chain.
Just to be clear again, the sprocket is 11-speed.
Why I did that is a "rice bowl" secret, so I won't say.
But separately from that,
there's an issue that occurred with the old Shimano 11-speed chain
and still occurs with the current Campagnolo 12-speed chain.
This sprocket contacts the freebody splines
at only two points—the outside and inside—
but a strange amount of metal powder
accumulates in the hollow freebody splines.
↑Like this when you remove the sprocket
The accumulation is partly due to chain oil, and
besides metal powder there's sand dirt mixed in, but
the dirt itself comes right off with just a paper towel wipe—no parts cleaner needed.
With the Shimano chain I did about 2000km,
and with the current chain I've ridden easily over 5000km from new . . .
Cleaned it.
Almost none of the sprocket's surface finish has flaked off.
The spline buildup—with a Shimano 11-speed chain it's
more pronounced (might even be magnetic enough to pick up with a magnet),
but the culprit seems to be "worn chain."
At 2000km when I swapped to a Shimano sprocket and cleaned it,
I couldn't even see wear marks from the roller engaging the tooth valley.
Currently at roughly 5000km from new,
on the frequently-used third and fourth cogs from the top,
there are wear marks only in the direction the chain roller engages.
By the way, the front ring is a 44T single.
For example, on Kimi Pass today, the cogs used ranged from
about one cog below the low gear to three below it,
but those cogs' tooth valleys have no wear marks.
In my commute these cogs aren't used at all,
but on a pass run you'd use them without fail,
so they have reasonable use history.
This sprocket's durability is extremely high,
but so high that it's hardness-mismatched with the chain,
making the chain life shorter.
It's like how the early black ball-race USB bearings
had ceramic balls in a ball race designed for steel balls—
due to hardness mismatch, they suffered from
frequent pitting failures in the races.
It's the same story.
Recently, KMC has announced regarding wind rumor that their own DLC
(diamond-like carbon, not downloadable content) coated chain
wears chainring teeth faster—"T-That's... not the case..."
But if lots of people didn't think "Wait, isn't chainring wear faster
with a DLC chain?", no such wind rumor would spring up in the first place.
Personally, I think "possible or not possible? It's possible."
What KMC's statement means isn't just
"DLC chains have no unusual wear or damage issues,"
it also means "we're not accepting claims that DLC chains caused
accelerated part wear," drawing a defensive line.
Since aftermarket aluminum pulleys with the same tooth count as OEM
need replacement more frequently than chainrings,
you can definitively say they wear faster, so
(→here)(→here)
if you did a wear test with a new aluminum pulley and DLC chain,
you might get wear results comparatively quickly.
I won't do it though.
Also, with a big pulley, even in aluminum,
the wear might be somewhat better.
What? You're saying you changed to a KMC DLC coated chain
and the wear on parts that contact the chain
(besides gears, like the inside of a front derailleur cage)
seems faster!?
Stop your whining, that's just your imagination.
But first. This is an image from the day right after I rode on the tire that got the slow puncture today.
April 30th of this year.
Exactly two months ago.
The location is the intersection in Ohno town at the base of Nabeya Pass.
It was already raining when I left home,
so I wore a rain jacket—or rather a waterproof wind breaker on top,
and didn't mind my shoes getting wet, but wore waterproof socks on the bottom.
I switched my race bib shorts to regular shorts.
I applied Wako's sunscreen to the exposed knees and shins.
It acts as a water-repelling waterproof coating and
doesn't come off unless you use cleansing—
just scrubbing with soap won't get it off.
I tend to use Wako's sunscreen more often for this purpose than actual sun protection,
but to do this you need temperatures warm enough that rain doesn't chill your knees.
I judged this day was right at the borderline of such temperatures,
so I didn't wear full-length rain pants.
With water-repelling legs and shorts, there's no interference with pedaling.
I intend to write an article someday about POLAR's poor
but the current VANTAGE V series
doesn't allow you to select "temperature" as a display item.
The previous V800 series, and even older RS and S series,
did allow you to select temperature as a display item.
It's not that they don't collect temperature data—
they record it in the background, so
when you download the ride data to a PC, you can view it afterward.
It's convenient to be able to see temperature in real time,
so you can confirm while riding things like "at this temperature I'll need thermal shoe covers"
or "what temperature was it when I took off my arm warmers?"
Those electronic display thermometers on the roadside
tend to show temperatures that are "conservative" compared to actual body sensation.
The temperature sensor is located away from the ground,
so it doesn't pick up ground heat reflection well, or
in summer the cycle computer shows higher temperatures,
and in winter it doesn't pick up the chill, so
the cycle computer tends to show lower temperatures.
This is especially pronounced when it's particularly hot.
Just now, when I checked the temperature recorded when the GPS trace was at Ohno town on April 30th,
it was 16.3°C.
At this temperature range it seems to be a zone where there's no upswing or downswing.
Today I had business at my mentor's place,
so I left home at 4 AM to be able to stop by around 8–9 AM.
Judging that going out of Osaka via Kazahuki Pass and back into Osaka via Kimi Pass
would work out well in terms of both time and route.
This is the Osaka-side entrance to Kazahuki Pass today.
It's called the "Osaka-side entrance,"
but you've already entered Wakayama Prefecture just before the tunnel,
so officially it's in Wakayama Prefecture.
By the way, the road station just before the tunnel is also in Wakayama Prefecture.
For some reason, I often see snails at this tunnel entrance.
I don't think they're the same individual, but I always see just one.
You can see it in the upper part of the image above,
In close-up, it looks like this.
It's producing feces so I don't think it's dead,
but the body is withdrawn into the shell and doesn't move.
This is from July 30th of last year.
I didn't take photos, but the next day
what appeared to be the same snail
had progressed about 10 meters into the tunnel,
and I was curious whether it would make it back alive.
This is from June 1st of this year.
I splashed water from my bottle on it.
No reaction.
I took a bit of a detour (about 200 meters round trip),
but this is the Great Gate of Kokawa Temple (Kokawa-dera).
↑My mental map of the area
Between Nabeya Pass and Kimi Pass there's Mt. Katsuragi,
but I almost never go there so I left it out.
Between Kazahuki Pass and Nabeya Pass there's Mt. Inunaki (Ikeda Tunnel),
which I climb sometimes, but I forgot to mark it.
Descending Kazahuki Pass, there's first a regional farm road, then below that the Kokawa-Kada Line,
and further down National Route 24,
but the Kokawa-Kada Line connecting Kada to Kokawa and merging with Route 24
has little traffic and few traffic lights, making it easy to ride.
If I rode the regional farm road I'd hit the Miyuki-tsuji South intersection at the base of Kimi Pass,
but the ups and downs are gnarly so I skip it.
After getting onto Route 24, I head east for a bit,
but soon I cross the Kino River to the south and ride to the base of Kimi Pass,
so I barely ride on Route 24.
↑It's like this, I just pass through it.
By the way, from Nabeya Pass you can ride up to Mt. Koya via National Route 480
(or rather, Nabeya Pass itself is Route 480), and
from Kimi Pass via National Route 371
(or rather, Kimi Pass itself is Route 371),
and they both converge at Yatate Teahouse, after which it's a single road.
So when I crossed the Kino River near Kokawa,
at a bridge joint that has a W-wave pattern,
there was a gap that was bigger than I expected, and carelessly I caused a rim strike.
I think it happened after that, but a fairly slow puncture
developed, and on the way back up Kimi Pass
I added air with a portable pump.
Just before that, there was a feeling of rim strike even at very small bumps.
From experience, when I notice a slow puncture and add air,
if I put in enough air that the internal pressure doesn't explode the sealant scab—
for example, about 4 bar—
the higher the pressure, the faster the air escapes, and
eventually it drops to about 2 bar, but
it often seems to stabilize at "an air pressure that barely leaks further."
But this time, the slow puncture went through that threshold and
leaked slowly but steadily on and on.
Separate from what I mentioned about adding air on Kimi Pass,
I also added air at the summit of Kimi Pass.
I pressurized it to the point where my finger wouldn't make a dent,
but I was still getting a feeling of rim strike on the descents of Kimi Pass at bumps.
↑This is the sealant scab.
I remembered it as "next to the round tire wear indicator near the valve,"
but since there are three valves it's hard to find.
This slow puncture wasn't caused by a scab burst, but rather
by a violent rim strike that partially compromised the tire bead seal.
That's my impression.
On the way back, I chose Kimi Pass because it's the closest pass to my mentor's workshop,
and I borrowed a floor pump there and gambled by putting in 5 bar,
at which point no scab burst occurred
(there was no "pop!" sound of the bead lifting either).
After chatting for about an hour, I headed out,
and when I checked before I left, the air hadn't leaked at all in that hour of sitting.
From there I passed in front of Brother Maintenance (→here)
and since Route 310 has a lot of traffic, I took an alternative back road one block in,
the Koya Kaido (which merges with Route 310 in Sakai),
and while riding that road, the scab burst three times,
spewing sealant with "pssh pssh pssh!" from the wound,
but as I kept riding it sealed itself back up and
just dropped to a lower pressure—and the sealant did its job in a few wheel rotations.
The air pressure when I got home was around 3 bar.
The slow puncture up to Kimi Pass
wasn't caused by a scab burst.
After the buckling of the bridge joint
there was an air leak with no lower limit, so to speak.
Probably even if there was no sealant scab at all, it would have happened.
On the way back from my mentor's place,
a scab burst occurred three times—something that didn't happen during the static hold at 5 bar—
but during that stretch I didn't feel any rim strike,
so it's almost certain that there was no continuous air leak
other than during the scab bursts.
The reason air was leaking before and after pumping with the floor pump
was different.
In the state where air was added at the summit of Kimi Pass,
the air would have continued to leak even at rest,
but after pumping with the floor pump,
the tire deformation from riding exceeded what it could handle,
and air only escaped if the scab couldn't hold—that's how it felt.
Then when I got home and looked at the bike,
sealant had splattered on the back of the seat tube.
The Cat Eye light in the leather case hanging from the saddle
also has sealant on it.
Since rain was forecast for that day, I put my wallet and phone in a waterproof pack
and carried a waterproof wind breaker in my back pocket,
but since it didn't rain during the time I rode, I didn't use them.
If I'd been riding in the rain, some of this sealant might have been washed off.
The puncture was on the right side, but sealant
had splattered even onto the back of the right crank's 4-arm.
It would be annoying if it dried completely,
so I scrubbed it off with a warm shower.
Unrelated to this, when you ride in summer and touch the underside of the top tube
and feel gritty from salt in your sweat,
if you can at least rinse it quickly with water,
or if that's difficult, wipe it with a damp cloth or paper towel,
making this a habit makes a significant difference
in the long-term damage accumulation to the frame.
The only frame you don't have to worry about this with is an unpainted titanium frame.
Even then, if the top tube's cable stop is blind-riveted rather than welded,
you should do it.
I've been told by customers multiple times,
"IRC's tubeless tires seem to puncture all the time."
I deliberately choose the S-Light knowing the puncture risk,
despite its being virtually unmatched in its lightness,
and since I ride pretty casually even in the rain
(I don't just get caught in rain, I ride even if it's already raining when I leave),
I'm not dissatisfied with the frequency of punctures.
The reason I say "virtually unmatched in its lightness" in the past tense
is because similar-weight tires are now available from other manufacturers,
and one of them, a certain Japanese brand that's not IRC,
has never made a decent road bike tire in the past—at least as far as I know—
and I've been burned by them many times,
so I'm leaving the role of being burned to other people.
If they ever made a decent tire, you'd hear such feedback.
Until then, I'm sitting this one out.
If I list a few examples of actual stories I've heard,
there's "the lightness you feel in your hands doesn't translate to rolling lightness,"
"it punctures immediately,"
"they supplied me with a tubular version, and it's a shit tire,"
"they said they'd give me one free if I wrote a report,
so I use it, but I wouldn't buy it to use,"
"(when I tried to refit the tire I'd removed for inspection)
I'm going back to Grand Prix 5000, so no tire needed,"
and similar things.
Also, I talked on the phone once with someone at a certain wholesale company
who is in some sense my senior in the bike business,
and the subject of that tire came up, and
he expressed surprise: "If you just do proper SNS advertising,
repeat customers aside, in the early stages it sells like that much?"r/>This senior was also a former pro rider,
so there was a time when he strictly upheld the pro job
of eating deliciously on camera, no matter what he truly thought
of what sponsors gave him,
and he may have had experience appearing to enjoy eating that brand's tire (so to speak).
Anyway, the tire that developed the slow puncture this time
has pretty worn tread, so
I decided to replace it, but I hadn't bought backup stock.
In such cases, as a makeshift measure, I'd normally
patch the back of the tire and use it until the same tire arrives,
but this time I decided to try
a Continental Grand Prix 5000S TR from the shop's inventory instead.
The actual measured weight for 25C is
just under 260g
(and as you can see in the image above,
I removed the 7-8g instruction sheet).
The 5000 TL, which was tubeless rather than tubeless ready,
was discontinued when the 5000S TR came out.
I've never used it (and never stocked it),
and at 300g measured weight in the narrowest 25C width,
I figured even if rolling was light, I didn't want it,
but from people who actually used it,
the feedback was mostly that compared to the tubed 5000,
before you could even feel the tubeless-specific ride quality,
the ride was abnormally sluggish and useless.
Also, the tire sidewall is thick and the bead is stiff,
so depending on the rim's internal width,
it's far harder to mount than a same-width tubed 5000,
and Mavic explicitly states that the only tubeless tire that fits Road UST tubeless rims
is Road UST tubeless tires, so while Mavic isn't wrong,
fitting it to a Mavic rim is extremely difficult,
and if you force it on, removing it in the field becomes
practically impossible for an ordinary person.
It's like equipping a cursed item in Dragon Quest.
You can only get it removed at the church.
While I've never stocked it,
I've handled it enough in inspections and such that
when I learned it was discontinued, I speculated there must have been
some awkward circumstances beyond the tire's performance.
With the 5000S TR, the tire bead is
considerably bulkier compared to the IRC.
There were no deformations like dents,
but there was a scrape on the rim side from the bridge joint buckling.
This definitely wasn't there until yesterday.
I really messed up there.
The bead protrusion is large.
People who started road cycling in the last couple of years
and have never ridden a rim-brake road bike
might not know, but before Grand Prix 5000,
there was a tire called Grand Prix 4000, and
it went through 4000 → 4000S → 4000S II as minor updates,
but with all of these models, at
the end of the casing just outside the tire-rim boundary,
threads would fray and stick out as a result of aging and use
(→here).
The 5000 TL came after 5000, but
for some reason the manufacturing was the same as the 4000,
and those threads that didn't appear on 5000
appeared on 5000 TL again.
I'm curious how this is on the 5000S TR.
Since the side is covered with rubber,
I suspect the threads won't appear, but.
With the IRC S-Light in 23C or 25C,
on the rims I use,
I've found from experience that I can mount and remove the tire without a tire lever.
I've confirmed that even with the tire mounted and bead seated to full pressure,
in its almost-new, unridden state, I can remove it without a lever.
So the portable tire lever I carry
is just one small one as insurance.
That's the IRC tire lever shortened
or the PB (famous for hex keys) tire lever in the image above.
In terms of pure tire lever performance, it's shorter even compared to the
Malni and Campagnolo (Fulcrum) ones above,
and since it has no curve, it's excellent for portability.
What concerned me was whether with the Grand Prix 5000S TR
I'd need to carry additional tire levers.
First, fitting: fitting the first bead to the rim required a tire lever.
Fitting the second bead was doable with hands only,
and surprisingly, the final part of seating the bead
was softer than the bead's thick appearance would suggest.
Getting the bead to seat via compressor
was quite smooth, and clearly easier than the IRC.
Incidentally, the IRC becomes pretty hard to get the bead up
if you use older, aged tires.
Most tire brands have that tendency,
but the IRC is especially pronounced.
Next, removing the tire from that state—
removing the first bead was doable by hand.
What surprised me was that the second bead also came off easily by hand.
Although fitting required a tire lever.
It seems unlikely that a single pressurization would have made the tire sidewall stretch that much,
so maybe I picked up some technique.
I think I can stick with just carrying one portable tire lever.
Fitted again.
Doable without a tire lever.
Second time I'madding Moji sealant.
Even though the tire width is 25C, I'm testing whether 35ml is sufficient.
↑This is the Grand Prix 4000 (on Racing Zero), but
the beginning of thread fraying and casing exposure look like this.
With the Grand Prix 5000S TR, given the way it's covered,
I suspect threads won't come out.
The sprocket is a Tni (Tني) chromoly 11-speed one (→here).
The supply of Shimano sprockets I was using before
wasn't stable
(↑that's written as if it's resolved now),
so I tried this, but after getting a 105 11-30T,
I went through a period of not using it.
This sprocket's shift performance is naturally inferior to genuine Shimano,
but it's not unusable,
but it seems that it doesn't fit the inner link width of Shimano 11-speed chains,
and the chain doesn't fully seat in the tooth valley,
so rarely, under hard acceleration or climbing torque
the chain slips forward.
I followed the sprocket's instruction to "start with a new chain,"
so chain wear isn't the cause.
That problem is now solved,
and I'm using a Campagnolo 12-speed chain.
Just to be clear again, the sprocket is 11-speed.
Why I did that is a "rice bowl" secret, so I won't say.
But separately from that,
there's an issue that occurred with the old Shimano 11-speed chain
and still occurs with the current Campagnolo 12-speed chain.
This sprocket contacts the freebody splines
at only two points—the outside and inside—
but a strange amount of metal powder
accumulates in the hollow freebody splines.
↑Like this when you remove the sprocket
The accumulation is partly due to chain oil, and
besides metal powder there's sand dirt mixed in, but
the dirt itself comes right off with just a paper towel wipe—no parts cleaner needed.
With the Shimano chain I did about 2000km,
and with the current chain I've ridden easily over 5000km from new . . .
Cleaned it.
Almost none of the sprocket's surface finish has flaked off.
The spline buildup—with a Shimano 11-speed chain it's
more pronounced (might even be magnetic enough to pick up with a magnet),
but the culprit seems to be "worn chain."
At 2000km when I swapped to a Shimano sprocket and cleaned it,
I couldn't even see wear marks from the roller engaging the tooth valley.
Currently at roughly 5000km from new,
on the frequently-used third and fourth cogs from the top,
there are wear marks only in the direction the chain roller engages.
By the way, the front ring is a 44T single.
For example, on Kimi Pass today, the cogs used ranged from
about one cog below the low gear to three below it,
but those cogs' tooth valleys have no wear marks.
In my commute these cogs aren't used at all,
but on a pass run you'd use them without fail,
so they have reasonable use history.
This sprocket's durability is extremely high,
but so high that it's hardness-mismatched with the chain,
making the chain life shorter.
It's like how the early black ball-race USB bearings
had ceramic balls in a ball race designed for steel balls—
due to hardness mismatch, they suffered from
frequent pitting failures in the races.
It's the same story.
Recently, KMC has announced regarding wind rumor that their own DLC
(diamond-like carbon, not downloadable content) coated chain
wears chainring teeth faster—"T-That's... not the case..."
But if lots of people didn't think "Wait, isn't chainring wear faster
with a DLC chain?", no such wind rumor would spring up in the first place.
Personally, I think "possible or not possible? It's possible."
What KMC's statement means isn't just
"DLC chains have no unusual wear or damage issues,"
it also means "we're not accepting claims that DLC chains caused
accelerated part wear," drawing a defensive line.
Since aftermarket aluminum pulleys with the same tooth count as OEM
need replacement more frequently than chainrings,
you can definitively say they wear faster, so
(→here)(→here)
if you did a wear test with a new aluminum pulley and DLC chain,
you might get wear results comparatively quickly.
I won't do it though.
Also, with a big pulley, even in aluminum,
the wear might be somewhat better.
What? You're saying you changed to a KMC DLC coated chain
and the wear on parts that contact the chain
(besides gears, like the inside of a front derailleur cage)
seems faster!?
Stop your whining, that's just your imagination.
Products Mentioned in This Article
- 🛒 IRC S-Light bicycle tire
- 🛒 Continental Grand Prix 5000S TR tire
- 🛒 Wako's sunscreen water-repellent
* Amazon affiliate links — prices may vary
Original Japanese post: のむラボ日記 #6742