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28 Flats Later

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28 Flats Later

Old 04-10-13, 07:53 PM
  #1  
Halla
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28 Flats Later

Any one have any idea why I keep getting a flat with the puncture or tear in the same place about every three weeks? Even sometimes a few hours after I install a new tube?

There's no debris in the rim or tire.

I've replaced the tube so many times I'm thinking about starting to drive...

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Old 04-10-13, 08:21 PM
  #2  
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That type of puncture looks like a pinch flat, but it's in sort of an odd spot by the valve stem. Possibility: how hard is it to get your pump off the valve stem after you air up?

-Jenrick
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Old 04-10-13, 08:37 PM
  #3  
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Bad rim tape?
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Old 04-10-13, 08:50 PM
  #4  
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I've seen that one a lot. (flat tires are a common repair item at work)
Here's what happens:
There is a stiff disk or rubber at the base of the valve
If the valve is not firmly pulled against the inside of the rim there will be a gap underneath this disk.
The more flexible rubber from the surrounding normal area of the tube, expands under inflation pressure and tries to fill this gap.
this causes localized stretching beyond the limits of the tube, hence the little tear you see.

the problem can occur upon tube installation if the valve isnt firmly pulled against rim.
or can occur in the future if the tube/tire is run underinflated and shifts around.

It is more common on narrow rims or those with a deep recessed area, where the stiff valve base area has a harder time squeezing inside.


Conclude:
on tube installation make sure the valve stem is bottommed out against the rim before full inflation.
keep tires consistently pressurized
when inflating check that valve is still in place, a valve that leans to one side is a warning that its probably not sitting flush inside the rim
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Old 04-10-13, 09:40 PM
  #5  
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Originally Posted by xenologer View Post
If the valve is not firmly pulled against the inside of the rim there will be a gap underneath this disk.
The more flexible rubber from the surrounding normal area of the tube, expands under inflation pressure and tries to fill this gap.
this causes localized stretching beyond the limits of the tube, hence the little tear you see.
+10,000

Thank you, Xenologer. I'm tired of typing the same answer.
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Old 04-10-13, 10:34 PM
  #6  
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Thank you Xenologer. Makes sense. Mobility means freedom to me and you've helped with that.
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Old 04-11-13, 10:00 AM
  #7  
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Originally Posted by xenologer View Post
I've seen that one a lot. (flat tires are a common repair item at work)
Here's what happens:
There is a stiff disk or rubber at the base of the valve
If the valve is not firmly pulled against the inside of the rim there will be a gap underneath this disk.
The more flexible rubber from the surrounding normal area of the tube, expands under inflation pressure and tries to fill this gap.
this causes localized stretching beyond the limits of the tube, hence the little tear you see.

the problem can occur upon tube installation if the valve isnt firmly pulled against rim.
or can occur in the future if the tube/tire is run underinflated and shifts around.

It is more common on narrow rims or those with a deep recessed area, where the stiff valve base area has a harder time squeezing inside.


Conclude:
on tube installation make sure the valve stem is bottommed out against the rim before full inflation.
keep tires consistently pressurized
when inflating check that valve is still in place, a valve that leans to one side is a warning that its probably not sitting flush inside the rim
Huh, I learn something new every day! I had just installed a new tube in ancient Wolber rim last week and had the same thing happen. Couldn't for the life of me figure out why the tube failed, as I'm retentive about the rim strip and being careful with the pump head.
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Old 04-11-13, 02:13 PM
  #8  
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Hi,

You need to keep tightening the outside valve retaining ring once
the tyre is properly seated (*) and have a good idea how much it
should stick out when it is properly seated on the rim.

rgds, sreten.

* The rubber valve seat can also get stuck under tyres in narrow
rims preventing proper tyre seating causing a bulge at the valve.
Usually on one side only and that I'd assume can cause the
same sort of tear in the innertube, I only noticed fitting my
tyres because the reflective rings made it much more obvious.

Last edited by sreten; 04-11-13 at 02:35 PM.
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Old 04-11-13, 02:46 PM
  #9  
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Whoa.
After mounting the tire and before inflating push the valve into the tire to allow the tire bead to seat properly into the rim walls. After the beads are fully seated then pull the tube to the rim (actually the pressure should do that for you).
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Old 04-11-13, 03:21 PM
  #10  
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Originally Posted by Al1943 View Post
Whoa.
After mounting the tire and before inflating push the valve into the tire to allow the tire bead to seat properly into the rim walls. After the beads are fully seated then pull the tube to the rim (actually the pressure should do that for you).
Hi,

Yes. If its not trapped, tyre pressure alone will correctly seat the valve.

rgds, sreten.

I think I did it wrong (with hindsight). Fitting a tyre start from
the valve (opposite to taking it off) and push the valve in to
make sure its not trapped at the low initial tensions involved.

Last edited by sreten; 04-11-13 at 03:37 PM.
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Old 04-11-13, 05:21 PM
  #11  
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FWIW, I once had problems mounting a latex tube when I tried to finish at the rim joint. I was used to mounting sew-ups by finishing opposite the valve and the thin tube kept getting trapped under the bead. I couldn't finish pushing the tube into the center without risking a tear. I had seen advice to finish at the valve and thought the advice was crazy.

What I finally figured out was that I could get the tube in by starting at the joint and working back to the valve. When I got to the valve, I could push the tube back into the tire with the valve, then finish with the bead.
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Old 02-15-19, 08:45 PM
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Seven
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Old 02-15-19, 08:46 PM
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Eight
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Old 02-15-19, 08:47 PM
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Eight
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Old 02-15-19, 09:27 PM
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Eight
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Old 02-15-19, 09:29 PM
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Nine
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Old 02-15-19, 09:34 PM
  #17  
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Ignore list made. Congrats!
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Old 02-16-19, 08:42 PM
  #18  
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I've had the same problem. I think it's just really cheap, poor quality control from tube makers. One solution that's been successful for me is using very thick, heavy, thorn proof tubes.

https://www.amazon.com/Sunlite-Thorn.../dp/B00129ACNI
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Old 02-18-19, 08:03 PM
  #19  
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Same problem here. It happens less on wider tires and much more on skinnies. It is caused by cheap manufacture. Never seen before the 1990s. Too many tubes have that exact failure straight out of the box, before even being inflated.

Schwalbe tubes are far from perfect, they seem to be best quality at this moment. There is nothing out there the quality of old Goodyear or Dunlop tubes, tubes that can still be used 60 years later. If you buy from UK Schwalbe can be had for less than $4 shipped. Otherwise widest tire practical for your bike and move towards bikes that take wider tires. Also, problem never occurs with tubulars.
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Old 02-18-19, 09:39 PM
  #20  
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Originally Posted by 63rickert View Post
Schwalbe tubes are far from perfect, they seem to be best quality at this moment.
Continental tubes are also very good.

I've never had a problem caused by the tube itself.


-Tim-
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Old 02-21-19, 12:06 AM
  #21  
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Flats

Originally Posted by Al1943 View Post
Whoa.
After mounting the tire and before inflating push the valve into the tire to allow the tire bead to seat properly into the rim walls. After the beads are fully seated then pull the tube to the rim (actually the pressure should do that for you).
​​​​​​
The tube can get stuck under the bead and inflating them pinches the tube. I put a little air in the tube after getting the tire back on and then make sure the tubes is not pinched especially near the valve. Like the previous poster said, push the valve into the tire to make sure their is no pinching then inflate before tightening the valve nut.
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