The tube from Panaracer's Purple Light (lightweight tube) that I have in my personal bike's rear wheel
had developed a super slow leak that would last about a day of riding.
The image above shows what I brought to the shop, but
after pumping it up a bit at home and leaving it in a floppy state,
I went out for about four hours of riding and came back
to find it had barely lost any air.
I suspected the valve core was loose, but that wasn't the issue.
I found a tiny puncture hole near the valve on the inside of the tube.
Looking at the corresponding position on the wheel side,
there was a tiny piece of rubber—basically a fragment of the rubber bead flashing hanging from the tire bead—
stuck to the rim tape.
Since it's not a hard granular object like sand, it's unclear if it caused the puncture,
but given that the puncture is on the inside
and there happened to be a small piece of rubber
on the rim tape exactly at that location,
it's quite likely there's a connection.
Panaracer doesn't make repair patches specifically for TPU tubes or Purple Light tubes,
and the Purple Light instruction manual states
"This product cannot be repaired if punctured,"
so it requires replacement. But since it's my personal bike
and it's a rear wheel tube
(if it were a front wheel tube, it could explode and be lethal,
so I wouldn't repair it or would move it to the rear),
I decided to attempt a patch repair.
Just to be clear, I'm noting this for completeness:
good readers, please don't try this at home!
↑These are repair patches for Tni's TPU tubes.
...I wrote that, but
if I phrase it as "These are" and "repair patches for Tni's TPU tubes,"
it could be read as patches exclusive to Tni's TPU tubes,
and if I'd written "patches for TPU tubes from Tni," it might sound
like they work with TPU tubes in general. But looking at the distributor's website,
they're explicitly stated to be patches exclusive to
Tni's LIGHT24 or LIGHT35 tubes.
You wipe the puncture area with an alcohol sheet and just stick on the patch—
it's a sticker-type format, a 4-pack set at 330 yen including tax.
Panaracer makes patches for butyl tubes called EasyPatch,
and those are also glueless patches like this one—
you just roughen the puncture area with sandpaper
and stick it on.
But if you keep using it as-is over time,
the tube's movement inside the tire causes it to gradually
wrinkle and eventually curl up and peel off.
Some people might think, "What kind of repair patch is that?!"
But EasyPatch is meant to be carried as insurance when you run out of spare tubes.
The idea is to be grateful that thanks to EasyPatch
you could ride home that day,
and then replace it with a new tube when you get home—
it's fundamentally a makeshift emergency measure.
Panaracer doesn't explicitly say "don't keep using a tube with a patch on it," though.
If you use TPU tubes,
carrying Tni patches (even if your TPU tube isn't from Tni)
might be a good idea for expanding your repair options.
So this time, I'm not using a glueless patch for the repair.
Next, this is the patch kit from Tubolito, which could be called the pioneer
of TPU tubes itself.
It comes with round or oval patches in the same color as their tubes,
and after roughening the puncture area with sandpaper
and wiping it with an alcohol sheet,
you apply rubber cement (made in collaboration with Tip Top, a German tire repair manufacturer)
and then
stick on the patch.
I could have used a smaller patch.
Actually, I've repaired a Tubolito tube before,
and I opened the rubber cement tube about a year ago,
but the contents haven't hardened—it still works fine.
The patch I applied is
so firmly bonded that even if I dig my nail under it,
I can't peel it off.
If this were a Tni glueless patch, it would be easy to lift.
I recovered the Purple Light that I'd been keeping in the rear wheel as
a "spare tube to keep by the front door."
It's stretched a bit from being pressurized once, but
it's fine for reuse.
had developed a super slow leak that would last about a day of riding.
The image above shows what I brought to the shop, but
after pumping it up a bit at home and leaving it in a floppy state,
I went out for about four hours of riding and came back
to find it had barely lost any air.
I suspected the valve core was loose, but that wasn't the issue.
I found a tiny puncture hole near the valve on the inside of the tube.
Looking at the corresponding position on the wheel side,
there was a tiny piece of rubber—basically a fragment of the rubber bead flashing hanging from the tire bead—
stuck to the rim tape.
Since it's not a hard granular object like sand, it's unclear if it caused the puncture,
but given that the puncture is on the inside
and there happened to be a small piece of rubber
on the rim tape exactly at that location,
it's quite likely there's a connection.
Panaracer doesn't make repair patches specifically for TPU tubes or Purple Light tubes,
and the Purple Light instruction manual states
"This product cannot be repaired if punctured,"
so it requires replacement. But since it's my personal bike
and it's a rear wheel tube
(if it were a front wheel tube, it could explode and be lethal,
so I wouldn't repair it or would move it to the rear),
I decided to attempt a patch repair.
Just to be clear, I'm noting this for completeness:
good readers, please don't try this at home!
↑These are repair patches for Tni's TPU tubes.
...I wrote that, but
if I phrase it as "These are" and "repair patches for Tni's TPU tubes,"
it could be read as patches exclusive to Tni's TPU tubes,
and if I'd written "patches for TPU tubes from Tni," it might sound
like they work with TPU tubes in general. But looking at the distributor's website,
they're explicitly stated to be patches exclusive to
Tni's LIGHT24 or LIGHT35 tubes.
You wipe the puncture area with an alcohol sheet and just stick on the patch—
it's a sticker-type format, a 4-pack set at 330 yen including tax.
Panaracer makes patches for butyl tubes called EasyPatch,
and those are also glueless patches like this one—
you just roughen the puncture area with sandpaper
and stick it on.
But if you keep using it as-is over time,
the tube's movement inside the tire causes it to gradually
wrinkle and eventually curl up and peel off.
Some people might think, "What kind of repair patch is that?!"
But EasyPatch is meant to be carried as insurance when you run out of spare tubes.
The idea is to be grateful that thanks to EasyPatch
you could ride home that day,
and then replace it with a new tube when you get home—
it's fundamentally a makeshift emergency measure.
Panaracer doesn't explicitly say "don't keep using a tube with a patch on it," though.
If you use TPU tubes,
carrying Tni patches (even if your TPU tube isn't from Tni)
might be a good idea for expanding your repair options.
So this time, I'm not using a glueless patch for the repair.
Next, this is the patch kit from Tubolito, which could be called the pioneer
of TPU tubes itself.
It comes with round or oval patches in the same color as their tubes,
and after roughening the puncture area with sandpaper
and wiping it with an alcohol sheet,
you apply rubber cement (made in collaboration with Tip Top, a German tire repair manufacturer)
and then
stick on the patch.
Actually, I've repaired a Tubolito tube before,
and I opened the rubber cement tube about a year ago,
but the contents haven't hardened—it still works fine.
The patch I applied is
so firmly bonded that even if I dig my nail under it,
I can't peel it off.
If this were a Tni glueless patch, it would be easy to lift.
I recovered the Purple Light that I'd been keeping in the rear wheel as
a "spare tube to keep by the front door."
It's stretched a bit from being pressurized once, but
it's fine for reuse.