Strange slow puncture problem?

[SteveK]

Yesterday when I woke up in the morning, the back tyre on my bicycle was 100% flat (I stupidly rode along a section of gravel pathway on 23mm tyres the evening before so wasn't surprised).

 

Patched up the innertube, put it all back together no problems at all. Rode almost 45k on the patched tyre yesterday and when I got home, the tyre was still as hard as when I set off. Great I thought, problem solved.

 

Woke up this morning and the tyre was not flat, but had gone down noticeably to maybe 75%, not enough to ride on. Not sure what's going on here, the patched innertube took so much abuse yesterday without losing pressure but then loses some overnight?

 

[WaveHunter]

I had that problem once; it turned out to be a worn inner tube valve.  It was a very slow leak, just like you describe with no hissing sound or bubbles, or any indication. 

 

Drove me crazy for a week trying to figure out what was going on, until bike shop simply replaced the valve for me...for free even! ????

 

Maybe just unscrew the valve and put a new one in (if there's a bike shop that is opened to get one from), or just buy a new inner tube off of Lazada.

Edited April 20, 2020 by WaveHunter

[SteveK]

That seems to explain it. No air is leaking from the tyre, at least not enough to produce even one bubble when held under water. I'm still using innertubes because that's what I know and trust and can change them at the side of the road in a few minutes.

[Lacessit]

Could be as WaveHunter suggests, or the patch has worked a tad loose.

[WaveHunter]

2 minutes ago, SteveK said:

That seems to explain it. No air is leaking from the tyre, at least not enough to produce even one bubble when held under water. I'm still using innertubes because that's what I know and trust and can change them at the side of the road in a few minutes.

That's the thing about valves; even in a tub of water I saw no bubbles so it's really deceptive, but you figure, over time they get a lot of abuse from topping off.

 

Agree with you about sticking with inner tubes; alternatives sound attractive but inner tubes make dealing with a flat so easy.

[damascase]

28 minutes ago, WaveHunter said:

I had that problem once; it turned out to be a worn inner tube valve.  It was a very slow leak, just like you describe with no hissing sound or bubbles, or any indication. 

 

Drove me crazy for a week trying to figure out what was going on, until bike shop simply replaced the valve for me...for free even! ????

 

Maybe just unscrew the valve and put a new one in (if there's a bike shop that is opened to get one from), or just buy a new inner tube off of Lazada.

Doesn’t that depend on the type of valve? I know you can put a new one in if you have the Schrader type (the one used in car tyres) but I do wonder whether that is possible with the Presta type.

Anyhow, another possibility is there is still a small sharp object in the tyre. Last week I had 3 flats before I found the very tiny piece of metal hidden in the tyre thread. You couldn’t see or feel it, but it was there and causing a pinhole in the innertube after a while, which was very hard to detect even in water.

Edited April 20, 2020 by damascase
Typo

[WaveHunter]

5 minutes ago, damascase said:

Doesn’t that depend on the type of valve? I know you can put a new one in if you have the Schrader type, but I do wonder whether that is possible with the Presta type.

Anyhow, another possibility is there is still a small sharp object in the tyre. Last week I had 3 flats before I found the very tiny piece of metal hidden in the tyre thread. You couldn’t see or feel it, but it was there and causing a pinhole in the innertbe after a while.

Most Presta types (not all) unscrew; kind of a pain but they do.  If it's the inner tube, it's pretty easy to see bubbles.  Buying a brand new inner tube is though is best, and cheap enough.

Edited April 20, 2020 by WaveHunter

[thaibeachlovers]

2 minutes ago, damascase said:

Doesn’t that depend on the type of valve? I know you can put a new one in if you have the Schrader type, but I do wonder whether that is possible with the Presta type.

Anyhow, another possibility is there is still a small sharp object in the tyre. Last week I had 3 flats before I found the very tiny piece of metal hidden in the tyre thread. You couldn’t see or feel it, but it was there and causing a pinhole in the innertube after a while.

I was going to say that. I had a slow leak in a tyre for ages. In the end found a very small nail protruding just enough to cause a pinhole. Not visible on the outside and too slow to make bubbles.

[Farmerkev]

WaveHunter is correct, change the valve or use new inner tube. When you inflate the inner tube the air molecules expand creating higher pressure below the valve keeping it fully closed, if not used the air cools down reducing the pressure allowing it to pass. 

[rvaviator]

You can replace both Presta and Schrader valve cores.

 

If you think the valve is leaking - and it does sound like that from what the OP reported - Put the bike wheel in a tray with water (leave the wheel on the bike) - You will start to see a air bubble slowly forming at the valve ...

[Ventenio]

something i do after a few flats, just for precaution.  NEW rim strip.  Even wrap some electrical tape around the rim for extra protection.  try a new innertube and tire, if possible.  if it goes flat, it's probably your rim and this nightmare will last until you get a new wheel.  also, try to get a schrader adapter for your presta innertube, so when you pump up the tire you aren't torquing the tube against that small hole and creating a small puncture.  best bet, a rim without those spoke holes.  if your rim doesn't have spoke holes, then it might simply some bad rubber on your tire and it's just bad luck that the tire weirdly attracts and holds on to extremely small pieces of metal.  experiment and experiment.  some tires are way better.  some tubes are way better.  

 

23 mm doesn't matter if your PSI is normal to above normal.

 

it usually comes in waves.  5 flats, then zero flats for months.  i'm sure i had a bad wheel and even a good rim strip couldn't stop those spoke holes from getting out of control. 

[WaveHunter]

5 minutes ago, rvaviator said:

You can replace both Presta and Schrader valve cores.

 

If you think the valve is leaking - and it does sound like that from what the OP reported - Put the bike wheel in a tray with water (leave the wheel on the bike) - You will start to see a air bubble slowly forming at the valve ...

Not necessarily.  Bubbles on the slick surface of an flexible inner tube are pretty easy to spot; not so on a valve because the leak from a worn valve may not even produce visible bubbles but still be leaking air very, very slowly.

 

Again, inner tubes are so cheap, that just seems like the easiest solution.

Edited April 20, 2020 by WaveHunter

[ravip]

7 minutes ago, WaveHunter said:

Most Presta types (not all) unscrew; kind of a pain but they do.  If it's the inner tube, it's pretty easy to see bubbles.  Buying a brand new inner tube is though is best, and cheap enough.

Absolutely right. A puncture on a bike is the last thing one would want!

[mickyr55]

Just get puncture proof tyres I have Shwalbe marathon plus on my bike well over 1200 miles not one puncture also had them on my      E-bike in the UK same result no punctures, very good tyres available on Lazada around 2k Bhatt for the pair.  ????????

 

[damascase]

10 minutes ago, WaveHunter said:

Most Presta types (not all) unscrew; kind of a pain but they do.  If it's the inner tube, it's pretty easy to see bubbles.  Buying a brand new inner tube is though is best, and cheap enough.

Buying/fitting a new inner tube will not help if there is a sharp object in the tyre thread, so one has to check that first. I know, I bought 3 new inner tubes last week for my MTB.....????????

[WaveHunter]

3 minutes ago, ravip said:

Absolutely right. A puncture on a bike is the last thing one would want!

It may be the last thing you want but if you ride off-road you can be certain of getting more than your fair share of them.  I've been on rides where I've gotten multiple flats on the same ride LOL! 

 

A good patch kit, and a very good mini pump, and spare inner tube and a few minutes on the side of the road will have you on your way in no time.

[WaveHunter]

3 minutes ago, damascase said:

Buying/fitting a new inner tube will not help if there is a sharp object in the tyre thread, so one has to check that first. I know, I bought 3 new inner tubes last week for my MTB.....????????

That's a good point!  Been there, done that ????

 

[ChouDoufu]

wee-tiny wires from steel belts or little slivers of glass can get embedded in the tread.  you could inspect the outer tread very closely to see if there's something hiding just under the surface that you can pick out with a pin or mini screwdriver.  might also run your fingers carefully along the inside of the casing to search for sharp points.

[rvaviator]

21 minutes ago, WaveHunter said:

Not necessarily.  Bubbles on the slick surface of an flexible inner tube are pretty easy to spot; not so on a valve because the leak from a worn valve may not even produce visible bubbles but still be leaking air very, very slowly.

 

Again, inner tubes are so cheap, that just seems like the easiest solution.

Agree with you ...  You do need a lot of patience to see the bubble from a slow leaking valve.  Hence the reason for just plonking the wheel in a tub of water and keep watching it for a few hours .. 5555 ...  Better than watching Thai TV ???? .. just ...

[RubbaJohnny]

I've often been let down in Thailand.

I think the temp and humidity acts faster esp on cheaper fixings.

Nil desperandum, inflation is always at hand.

I have a home compressor but a basin of water and a manual achieves the same with a bit of effort.

I hope youll be pumped soon.♻️

 

[WaveHunter]

8 minutes ago, rvaviator said:

Agree with you ...  You do need a lot of patience to see the bubble from a slow leaking valve.  Hence the reason for just plonking the wheel in a tub of water and keep watching it for a few hours .. 5555 ...  Better than watching Thai TV ???? .. just ...

LOL!  Thai TV is tortuous for sure; the only thing worse is Thai pop-up commercials that constantly come up on YouTube...some of the cheesiest things I've ever seen. 

 

So, let's see...watching hours on end for bubbles or watching Thai TV ... yeah, I'll pick the bubbles for sure!

 

I'll just add it to my fun things to do while on Lockdown, like watching grass grow, or paint dry.

Edited April 20, 2020 by WaveHunter

[scubascuba3]

Tubes in Decathlon are only 100 baht and are fine.

 

If you can't find the cause take the tyre off and turn it inside out and check for those small bits of metal or glass mentioned above

[frequentatore]

When I fix an inner tube at home, I inflate it and wait 2 days...

If you are not sure about the valve or the fix, tie a piece of sewing thread around the inflated tube and wait a few days.

[StreetCowboy]

I believe that the cheap Kenda tubes puncture more easily than the expensive Bontrager tubes.  I don't know about the Maxxis ones.  It's certainly true that the Schwalbe Marathons give me less punctures, although since I've started running my tyres at the high end of their nominal range I've had very few.

THe last time I replaced a Schwalbe Marathon, it had lasted longer than the chain.  I replaced it because it was getting thin, and had a hold in it from a metal rod a few cm long and a few mm in diameter that had gone completely into the tyre and was not visible from the outside, but only gave a slow puncture (about an hour from full inflation so softer than ... well, whatever.  It did give a little clicking sound, but since it was not visible to the eye, I had carried on.  My spare tube had a problem - it had been in my bag for the best part of a year - so I patched the hole, and rode away contented some time later; to be disappointed in the morning when the tyre was flat again,  So another new tube, and I resolved then to replace the tyre.

Once again, apologies for the completely irrelevant anecdote.

 

SC

[Rookiescot]

Someone is letting your tyre down during the hours of darkness.

 

Some people hate cyclists. No idea why. Its not like some of them behave like a$$holes is it?

[StreetCowboy]

3 hours ago, scubascuba3 said:

Tubes in Decathlon are only 100 baht and are fine.

 

If you can't find the cause take the tyre off and turn it inside out and check for those small bits of metal or glass mentioned above

Use your finger to lightly trace over the inside of the tyre; you'll feel things that are too small to see, and too small to pierce all the way through your skin.  I had one tiny bit of wire that was not as long as the tyre was thick - there was just a point sticking out when the tyre was flattened.  I had to push it through from the outside.

When you're fitting your tyre. If you place your tyre so that there is a distinguishing mark (a logo, or a specific letter in the printing) against the valve, you can figure out where to look for the object based on where the puncture was; this works better if you are careful not to turn the tyre round when you take it off!

[SteveK]

Well, woke up today and tyre was 100% fine, figure that one out.

 

Been out on it today although the weather is absolutely brutal. Trying to cycle reasonable distances whilst being burnt and boiled is not easy.

 

 

[WaveHunter]

28 minutes ago, SteveK said:

Well, woke up today and tyre was 100% fine, figure that one out.

 

Been out on it today although the weather is absolutely brutal. Trying to cycle reasonable distances whilst being burnt and boiled is not easy.

 

 

Where do you ride?  I'm in Chiang Mai.  I don't mind the heat so much but the pollution we've been experiencing lately absolutely sucks! 

 

Air Quality Index (click link) today is 166, and has not been close to 100 (acceptable AQI for riding) in well over one month!.  I have been riding every once in a while with a mask but I don't think it helps much. 

 

Check out international news and you'll see that Chiang Mai now has the dubious distinction of being the most polluted city in the entire world!

 

 

Adding to this, worries about COVID-19 are keeping most riders off the road so very lonely climbs on Doi Suthep. 

 

This all really bites; I'm only in Chiang Mai for the riding, and right now this is about the worst place I can imagine being!

 

Edited April 21, 2020 by WaveHunter

[scubascuba3]

38 minutes ago, SteveK said:

Well, woke up today and tyre was 100% fine, figure that one out.

 

Been out on it today although the weather is absolutely brutal. Trying to cycle reasonable distances whilst being burnt and boiled is not easy.

 

 

You need to cycle early 6am-ish, otherwise the temperature really goes up quickly, today i think 33 but feels like 41 forecast said

[SteveK]

3 minutes ago, scubascuba3 said:

You need to cycle early 6am-ish, otherwise the temperature really goes up quickly, today i think 33 but feels like 41 forecast said

Yeah, normally try to do that but last night was watching Better Call Saul until the wee hours and woke up late.

 

My phone is saying 40 degrees. When you're whizzing along it feels OK, but if I slow down or stop for any reason I start to feel like a piece of KFC chicken.