Patching Blowouts on 19mm tubes



meb

New Member
Aug 21, 2003
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I attempted to patch a blowout on a road tube. The largest patch from the kit circles a majority of the tube, and left no flexibility for the tube to expand, and failed to hold when pumped up.

Given the greater size of a blowout relative a typical puncture or pinch flat, and the irregular star shape, I'm wondering are blowouts patchable?

Is there any special technique or does one just toss in the towel?
 
meb wrote:
> I attempted to patch a blowout on a road tube. The largest patch from
> the kit circles a majority of the tube, and left no flexibility for the
> tube to expand, and failed to hold when pumped up.
>
> Given the greater size of a blowout relative a typical puncture or
> pinch flat, and the irregular star shape, I'm wondering are blowouts
> patchable?
>
> Is there any special technique or does one just toss in the towel?
>

I would throw in the towel. Upgrade to 23 mm wide tires, which are
faster than 19 mm tires everywhere but the velodrome, since the reduced
rolling resistance from the greater width more than compensates for the
greater frontal area at inflation pressures that are usable on the street.

--
Tom Sherman - Holstein-Friesland Bovinia
"And never forget, life ultimately makes failures of all people."
- A. Derleth
 
On Jan 27, 2:39 am, meb <[email protected]>
wrote:
> I attempted to patch a blowout on a road tube. The largest patch from
> the kit circles a majority of the tube, and left no flexibility for the
> tube to expand, and failed to hold when pumped up.
>
> Given the greater size of a blowout relative a typical puncture or
> pinch flat, and the irregular star shape, I'm wondering are blowouts
> patchable?
>
> Is there any special technique or does one just toss in the towel?


Nonsense!

http://www.bbc.co.uk/cult/hitchhikers/guide/towel.shtml

http://www.towel.org.uk/index.php/The_Hitchhiker's_Guide_to_the_Towel
 
On Jan 27, 5:33 am, Tom Sherman <[email protected]>
wrote:
> meb wrote:
> > I attempted to patch a blowout on a road tube.  The largest patch from
> > the kit circles a majority of the tube, and left no flexibility for the
> > tube to expand, and failed to hold when pumped up.

>
> > Given the greater size of a blowout relative a typical puncture or
> > pinch flat, and the irregular star shape, I'm wondering are blowouts
> > patchable?

>
> > Is there any special technique or does one just toss in the towel?

>
> I would throw in the towel. Upgrade to 23 mm wide tires, which are
> faster than 19 mm tires everywhere but the velodrome, since the reduced
> rolling resistance from the greater width more than compensates for the
> greater frontal area at inflation pressures that are usable on the street.
>

I agree with Tom. I use 700x25 wide tires and find no loss of
"performance" from 23s. In fact, I think I roll ALOT faster with my
25mm slicks!

However, if you really have to use 19mm wide tires, and still want to
patch your tubes, then you need to get small patches like these Rema
20mm:

http://www.biketoolsetc.com/index.c...r-Kits-and-Supplies&tc=Patches&item_id=RE-F0P

Good Luck!
 
On Jan 27, 1:39 am, meb <[email protected]>
wrote:
> I attempted to patch a blowout on a road tube.  The largest patch from
> the kit circles a majority of the tube, and left no flexibility for the
> tube to expand, and failed to hold when pumped up.
>
> Given the greater size of a blowout relative a typical puncture or
> pinch flat, and the irregular star shape, I'm wondering are blowouts
> patchable?
>
> Is there any special technique or does one just toss in the towel?


First, even patches have some stretch so make sure you have applied
the patch properly.
The technique is thoroughly described here:
http://www.sheldonbrown.com/flats.html#patching

Since are referring to a large star shaped "blowout" (as opposed to a
"typical puncture"), if you follow the technique described in the
link above and still have problems, it's probably time to dispose of
the tube.

Second, I'm not sure why the subject of TIRE size came up, you were
referring to a small TUBE, right?

Most 700c tubes are sized to fit a range such as 19 or 20 to 25 mm
tires. Such a tube would need to expand *more* to fill a 25 mm tire
than to fill a 19 mm tire. In other words, any problem of lack of
expansion of the tube would be GREATER in a wider tire.

And yes, patches become very awkward to use when their diameter
exceeds the width of the deflated tube when it is laid flat.
Smaller patches are generally more practical for most patching of road
tubes.
Such as:
http://www.jensonusa.com/store/product/TL308I04-Rema+F0-P+16Mm+Round+Patches..aspx?sc=FRGL

For comparison, a US dime is just under 18mm in diameter

DR
 
meb <[email protected]> wrote in news:meb.33u6z0@no-
mx.forums.cyclingforums.com:
> Given the greater size of a blowout relative a typical puncture or
> pinch flat, and the irregular star shape, I'm wondering are blowouts
> patchable?



1. If your patches are too big, use smaller patches. Patches come in
different sizes, though the smaller ones are a little harder to find.

2. If the hole in your tube is more than half the diameter of the tube, then
toss the tube. Only small holes are easily patched.
 
On Jan 27, 12:52 pm, DirtRoadie <[email protected]> wrote:
> On Jan 27, 1:39 am, meb <[email protected]>
> wrote:
>
> > I attempted to patch a blowout on a road tube.  The largest patch from
> > the kit circles a majority of the tube, and left no flexibility for the
> > tube to expand, and failed to hold when pumped up.

>
> > Given the greater size of a blowout relative a typical puncture or
> > pinch flat, and the irregular star shape, I'm wondering are blowouts
> > patchable?

>
> > Is there any special technique or does one just toss in the towel?

>
> First, even patches have some stretch so make sure you have  applied
> the patch properly.
> The technique is thoroughly described here:http://www.sheldonbrown.com/flats.html#patching
>
> Since are referring to a large star shaped "blowout" (as opposed to a
> "typical puncture"),  if you follow the technique described in the
> link above and still have problems, it's probably time to dispose of
> the tube.
>
> Second, I'm not sure why the subject of TIRE size came up,  you were
> referring to a small TUBE, right?
>


Most kit patches are a bit (lot) thicker than they need to
become or work or have (be), in addition to yours being
obviously
too large. Take an old, junked, thin tube, cut a small circle:
couple to morethanacouple mm (25.4ths of an inch) bigger
than what covers: sand the pease out of it, until it's even
thinner (knife demonstration tomato thin) (come to think
of it, you can do this /in situ/), apply cement to the bit, and
thinly to the tube as well. Wait.

A bit longer.

Actually, just wait >15 minutes. And stick 'em together, ass-
uring yourself they're obsessively flatly mated. Then pretend
you are a pastry chef and roll that sucker flat. Probably don't
inflate for a day or so so's it can set well.

This is not a roadside repair, obviously.
 
> 2. If the hole in your tube is more than half the diameter of the tube,
> then
> toss the tube. Only small holes are easily patched.


Or *safely* patchable. My life depends upon my tires (more correctly, my
tubes) holding air. On a given ride I might spend 20-30 minutes descending
at speeds I'd rather not suddenly lose air pressure. I'll patch very small
holes, but anything over a 1/4 inch I don't even try. Fortunately it's not
much of an issue anyway, as I tend to get one flat every 3k miles or so.

--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com


"sally" <[email protected]> wrote in message
news:[email protected]...
> meb <[email protected]> wrote in
> news:meb.33u6z0@no-
> mx.forums.cyclingforums.com:
>> Given the greater size of a blowout relative a typical puncture or
>> pinch flat, and the irregular star shape, I'm wondering are blowouts
>> patchable?

>
>
> 1. If your patches are too big, use smaller patches. Patches come in
> different sizes, though the smaller ones are a little harder to find.
>
> 2. If the hole in your tube is more than half the diameter of the tube,
> then
> toss the tube. Only small holes are easily patched.
 
"meb" <[email protected]> wrote in message
news:[email protected]...
>
> I attempted to patch a blowout on a road tube. The largest patch from
> the kit circles a majority of the tube, and left no flexibility for the
> tube to expand, and failed to hold when pumped up.
>
> Given the greater size of a blowout relative a typical puncture or
> pinch flat, and the irregular star shape, I'm wondering are blowouts
> patchable?
>
> Is there any special technique or does one just toss in the towel?
>
>
> --
> meb
>


I have been known to cut patches to size.

Is that wrong?

Dave

Noblesville, Indiana
 
On Jan 27, 8:51 pm, "Dave Reckoning" <[email protected]> wrote:

>
> I have been known to cut patches to size.
>
> Is that wrong?


Don't you lose the nice tapered edge when you do that?

DR
 
DirtRoadie said:
On Jan 27, 1:39*am, meb <[email protected]>
wrote:
> I attempted to patch a blowout on a road tube. *The largest patch from
> the kit circles a majority of the tube, and left no flexibility for the
> tube to expand, and failed to hold when pumped up.
>
> Given the greater size of a blowout relative a typical puncture or
> pinch flat, and the irregular star shape, I'm wondering are blowouts
> patchable?
>
> Is there any special technique or does one just toss in the towel?


First, even patches have some stretch so make sure you have applied
the patch properly.
The technique is thoroughly described here:
http://www.sheldonbrown.com/flats.html#patching

Since are referring to a large star shaped "blowout" (as opposed to a
"typical puncture"), if you follow the technique described in the
link above and still have problems, it's probably time to dispose of
the tube.

Second, I'm not sure why the subject of TIRE size came up, you were
referring to a small TUBE, right?

Most 700c tubes are sized to fit a range such as 19 or 20 to 25 mm
tires. Such a tube would need to expand *more* to fill a 25 mm tire
than to fill a 19 mm tire. In other words, any problem of lack of
expansion of the tube would be GREATER in a wider tire.

And yes, patches become very awkward to use when their diameter
exceeds the width of the deflated tube when it is laid flat.
Smaller patches are generally more practical for most patching of road
tubes.
Such as:
http://www.jensonusa.com/store/product/TL308I04-Rema+F0-P+16Mm+Round+Patches..aspx?sc=FRGL

For comparison, a US dime is just under 18mm in diameter

DR

Yes, we are talking about tubes.
 
On Jan 27, 12:52*pm, DirtRoadie <[email protected]> wrote:
> On Jan 27, 1:39*am, meb <[email protected]>
> wrote:
>
> > I attempted to patch a blowout on a road tube. *The largest patch from
> > the kit circles a majority of the tube, and left no flexibility for the
> > tube to expand, and failed to hold when pumped up.

>
> > Given the greater size of a blowout relative a typical puncture or
> > pinch flat, and the irregular star shape, I'm wondering are blowouts
> > patchable?

>
> > Is there any special technique or does one just toss in the towel?

>
> First, even patches have some stretch so make sure you have *applied
> the patch properly.
> The technique is thoroughly described here:http://www.sheldonbrown.com/flats.html#patching
>
> Since are referring to a large star shaped "blowout" (as opposed to a
> "typical puncture"), *if you follow the technique described in the
> link above and still have problems, it's probably time to dispose of
> the tube.
>
> Second, I'm not sure why the subject of TIRE size came up, *you were
> referring to a small TUBE, right?
>


Most kit patches are a bit (lot) thicker than they need to
become or work or have (be), in addition to yours being
obviously
too large. Take an old, junked, thin tube, cut a small circle:
couple to morethanacouple mm (25.4ths of an inch) bigger
than what covers: sand the pease out of it, until it's even
thinner (knife demonstration tomato thin) (come to think
of it, you can do this /in situ/), apply cement to the bit, and
thinly to the tube as well. Wait.

A bit longer.

Actually, just wait >15 minutes. And stick 'em together, ass-
uring yourself they're obsessively flatly mated. Then pretend
you are a pastry chef and roll that sucker flat. Probably don't
inflate for a day or so so's it can set well.

This is not a roadside repair, obviously.

I had considered cutting up another tube due the flexibility issue.