Tire Pressure & relationship to punctures

On Wed, 24 Aug 2005 07:46:20 -0600, (Mark D)
wrote:

For awhile last year, I was doing a lot of highway shoulder riding, and
was virtually flatting every ride. (Vittoria Open Corsa CX)

A couple were thorns (or those goatheads as they call them) But largely,
they were minute punctures that looked like someone poked the tube with
a hypodermic needle.

Mostly, I was lucky, in that I'd make it home, and then notice the flat
the next day before a ride, but once got caught 24 miles out (according
to my computer)

I was told by my LBS owner, that what I am typically picking up out on
the highways, is small minute metal wires left by Semi-truck tires. I
don't know how accurate this is, but it sounds quite possible.

Since I've refrained this year from riding highway shoulders in-out of
town, I've only flatted once, and it was a thorn.

This may be what's happening with you?
For awhile there, I thought I was going to have to buy stock in some
innertube company! lol
Mark D.

Dear Mark,

What are known as Michelin wires can make tiny holes in
tubes, but so can goatheads, which have three methods of
impaling tires.

Modest thorns prefer to give the tire a sharp jab and then
let themselves be torn free without sticking around (sorry,
couldn't help that). They leave no trace beyond a pinhole
and make you feel foolish and frustrated as you run finger
or thumb around the inside of the tire repeatedly without
finding the culprit.

Clumsier thorns get stuck in and then break off, leaving a
tiny thorn that must later be found and then dug out of the
tire--a paper-clip hung on the zipper of a bike-bag is
useful, but the tongue of a wrist-watch buckle can be used,
though it's really too big.

Exhibitionist goatheads catch your eye--what's that yellow
thing whipping around on the side of the front tire? When
you stop, the tire may still be holding air, with not even a
hiss as you hold your ear close to the gloating thorn.

The filthy vines are just about ready to start dropping the
ripe thorns now around here.

Carl Fogel

Carl Fogel writes:

Exhibitionist goatheads catch your eye--what's that yellow thing
whipping around on the side of the front tire? When you stop, the
tire may still be holding air, with not even a hiss as you hold your
ear close to the gloating thorn.

The filthy vines are just about ready to start dropping the ripe
thorns now around here.

Puncture vine (aka Tribulus terrestris) produces thorns throughout its
summer existence even a weak or so after the first blossoms appear,
and they do that shortly after the plant produces leaves. Five segment
seed pods of dense hard wood are produced continuously while the plant
grows and blooms. There is no ripening part of the season. See pix:

http://www.sheldonbrown.com/brandt/thorns.html

Jobst Brandt

On Wed, 24 Aug 2005 18:40:07 GMT,
wrote:

Carl Fogel writes:

Exhibitionist goatheads catch your eye--what's that yellow thing
whipping around on the side of the front tire? When you stop, the
tire may still be holding air, with not even a hiss as you hold your
ear close to the gloating thorn.

The filthy vines are just about ready to start dropping the ripe
thorns now around here.

Puncture vine (aka Tribulus terrestris) produces thorns throughout its
summer existence even a weak or so after the first blossoms appear,
and they do that shortly after the plant produces leaves. Five segment
seed pods of dense hard wood are produced continuously while the plant
grows and blooms. There is no ripening part of the season. See pix:

http://www.sheldonbrown.com/brandt/thorns.html

Jobst Brandt

Dear Jobst,

The thorns start out green and soft, take a while to grow
brown and harden, and then they fall off----it's called
ripening and is quite noticeable.

Since the rains typically come late in summer around Pueblo,
the growth occurs late in the summer, giving the process a
rather seasonal nature.

Thorns from the last century or so are still available to
provide punctures in the previous eleven months of the year.

See the plants actually growing, as I do every day.

(The ones sending a single damned tendril along the cracks
are now about 2/3's of the way across my bicycle path, with
happy little green thorns growing on them.)

Carl Fogel

Carl Fogel writes:

Exhibitionist goatheads catch your eye--what's that yellow thing
whipping around on the side of the front tire? When you stop, the
tire may still be holding air, with not even a hiss as you hold your
ear close to the gloating thorn.

The filthy vines are just about ready to start dropping the ripe
thorns now around here.

Puncture vine (aka Tribulus terrestris) produces thorns throughout
its summer existence even a weak or so after the first blossoms
appear, and they do that shortly after the plant produces
leaves. Five segment seed pods of dense hard wood are produced
continuously while the plant grows and blooms. There is no
ripening part of the season. See pix:

http://www.sheldonbrown.com/brandt/thorns.html

The thorns start out green and soft, take a while to grow brown and
harden, and then they fall off----it's called ripening and is quite
noticeable.

I'm not convinced that the plant doesn't get started in spring with the
first warm weather as it does in most other areas. Are you sure you
couldn't find any in late May or June?

Since the rains typically come late in summer around Pueblo, the
growth occurs late in the summer, giving the process a rather
seasonal nature.

Puncture vine doesn't need any rains, it producing a tap root that
reaches more than three feet below the surface.

Thorns from the last century or so are still available to provide
punctures in the previous eleven months of the year.

This makes me think of doing an experiment. Because we have no
puncture vine flats during the cooler, wet parts of the year here, I
assumed they get dissolved. I'll have to look into this. As I have
mentioned, areas where the road department did not spray herbicides,
other roadside plants grew and there are no traces of the spiny pods,
plants or dried up tendrils from previous infestation. That I have
looked into at length.

See the plants actually growing, as I do every day.

We have roads where there are thick mats of them. Notice how when
transmitting sunshine the leaves are light green and in reflective
mode are dark green. The blossoms are a cheery canary yellow all the
time.

(The ones sending a single damned tendril along the cracks are now
about 2/3's of the way across my bicycle path, with happy little
green thorns growing on them.)

Even green thorns are capable of causing flats if they are broken into
single pods, as they are by people who inadvertently ride through a
thicket.

Jobst Brandt