Werehatrack said:Quoted message said:Over in rec.bicycles.tech, Jobst Brandt argues that flint flats are
just a myth:
"I keep hearing about these mysterious cherts [flints] yet have never
seen one on the road or in a tire. I ride many miles of rocky roads
here and in Europe and have not had a flat from these mysterious sharp
rocks that don't seem to cut car tires or we could find examples of
them embedded in the surface of car tires."
http://groups.google.com/group/rec.bicycles.tech/msg/97f538aa81f0f1ed
May the gods of perversity visit him for that one. The mere fact that
it has not happened to him is not proof that it does not occur.
If I had been prescient enough to find it for him back in 1976, I
possibly could have brought him the stone that poked a hole in the
tire of my '67 VW Van on a road in Montana, but he thoughtlessly
failed to let me know that he wanted it. The road was freshly graded
and gravelled, and I was so certain that there must have been
something other than a rock involved that I spent the better part of
half an hour searching the road for the offending object. The search
was fruitless, of course; under the assumption that a rock couldn't do
the deed, I looked for anything else...but rocks were the only
possible cause. The majority of the rocks were 35 to 70mm in size,
and they were freshly crushed rather than rounded river rock. Sharp
edges abounded, but I ignored them. Finally, I gave up the quest for
the puncture's cause, mounted the spare, and carefully made my way
back to civilization to get the sanctified tire cursed again.
The guy at the tire store knew just which road section was involved.
He'd had several flats to fix that day due to that road and another
which had received similar treatment by the DOT.
Perhaps more to the point, however, in a conversation I had years ago
with one of the engineers at Armstrong (are they still in business?)
he noted that stone-induced holes are exceedingly rare on car tires
now that steel belts are the norm under the tread, and even in those
cases where they still occur, they seldom leave a rock in the breach.
Sometimes, that's because the stone causes a rupture rather than a
puncture; the stone never actually penetrates the surface, but deforms
it so severely that it tears from the inside. When that occurs, the
cords on the inside show a burst pattern rather than a cut. Tire
punctures due to an outright cut from a rock do occur, though, but the
rock is seldom still in the cut when the tire is removed; such rocks
are almost never shaped regularly enough, with a small enough
cross-section with nearly parallel sides, that they get trapped by the
tire material. They poke a hole and get blown back out.
Quoted message said:Primitive superstitions about flints still flourish in the UK and
Denmark, so I'm asking for your views on the matter, somewhat like a
sociologist asking about the Loch Ness monster.
The Loch Ness Monster, on the other hand, is a known hoax, while the
stone-cut tire is not.
Quoted message said:Any pictures of flints in tires and tubes would be interesting, even
though they must be obvious fakes.
I suspect that it's just such a matter-of-course occurrence in such
areas that they don't bother taking pictures. To them, I'm sure that
it would be like making photo documentation of dryer lint; why bother?
(Nessie, on the other hand, is a subject whose photo is worth real
money; I can just imagine the melee that would ensue should that
mythical beast surface before a crowd of Scots with cameras in hand.)
Quoted message said:(Alas, the nearby sand and gravel pit closed a few years ago, so I'm no
longer able to photograph the flint flats whose existence Jobst
denies.)
And I live in an area where the odd rock is more often a shard of
oyster shell, with less probability of puncturing a tire than the far
more common (on the road, at any rate) shards of broken glass and
plastic remaining from the most recent auto collisions. Still, for
me, the puncturing object is still in the tire only about half the
time with street flats, and less than that when off-road.
Dear Werehatrack,
Yes, my impression is that flats from what the UK crowd and the Danes
call flints are so common that they'll be amused by this thread.
I don't doubt that Jobst's tires are unsullied by such thoughtless
rock chips, but his habit of denying the existence of anything outside
his experience grows tiresome. Right now, he's evading the issue in
several posts, with red herring quibbles about who first used the term
"Michelin wire" and blather about how terrible I am to ride where I
live and take pictures that don't support his theories about
goatheads.
What's actually interesting is how the stone-chip flats seem to be
much more common in England and Denmark. I wondered if it was just
some local road-building custom, but a post in this thread mentions
that the rugby teams in one area search the grass for flints before
games, which suggests that the evil little things are part of the
general landscape.
For what it's worth, here's the shortest and sharpest (sorry, can't
resist it) comment that I've found in the archives about the
supposedly non-existent flints:
Andrew Muzi of yellowjersey.org in Wisconsin wrote skeptically about
the danger of checking for sharp objects inside flat tires:
"Myth. Having run my fingers inside literally many thousands of
tires, often with nicely mounted glass shards, staples, wire, nails
and evey imaginable penetrating object, I cannot recall ever having
cut my finger while wiping the inside of a tire."
David Damerell of the UK replied:
"I have once, on a flint. However, I don't think it's worth buggering
about with cotton balls to prevent one trivial injury in many years of
riding."
http://groups.google.com/group/rec.bicycles.tech/msg/64c1101610ba1d6e
As a sidelight, a friend of mine startled me recently by casually
mentioning that he expects two or three flat tires per year just
driving his car. He started ticking off flats in the last year in his
car, his wife's car, his parents' car, and rental cars, all just
driving around paved streets all over the western US. The tires were
new, not worn out.
After I decided that my friend wasn't joking, I told him that he
certainly won't be borrowing my car. Tthis seemed like a more
practical approach than the Jobstian tactic of telling him that he was
mistaken.
Around here, we actually have a phrase to describe a certain
personality: "He'd argue with a flat tire."
Cheers,
Carl Fogel
