Thorn catchers in the TDF

Quoted message said:

A 1934 all-wire rear-tire saver, trailing for a change:

http://www.wooljersey.com/gallery/v/aldoross/pd/back_brake_1934.jpg.html

Here's where that photo came from:

http://www.wooljersey.com/gallery/v/aldoross/pd/Magne34.JPG.html?g2_imageViewsIndex=1

See what I mean about huge and gorgeous pictures? No front thorn
catcher for the 1934 TDF winner Antonin Magne, but I'm not sure if the
prevalence of rear protection is real or just apparent because they're
harder to see in front.

Oops! Enlarged, Magne seems to have a leading front tongue-style thorn
catcher (as opposed to his obvious rear wire model):

http://i17.tinypic.com/80vn3g5.jpg

At least I can't think what else it could be. I mistook it for the
solid metal of the caliper brake on the far side of the tire, but it's
much too high above the rim and a little daylight can be seen between
it and the tire.

Cheers,

Carl Fogel

In article <[email hidden]>,

Quoted message said:

Quoted message said:

A 1934 all-wire rear-tire saver, trailing for a change:

http://www.wooljersey.com/gallery/v/aldoross/pd/back_brake_1934.jpg.html

Here's where that photo came from:

http://www.wooljersey.com/gallery/v/aldoross/pd/Magne34.JPG.html?g2_imageView
sIndex=1

See what I mean about huge and gorgeous pictures? No front thorn
catcher for the 1934 TDF winner Antonin Magne, but I'm not sure if the
prevalence of rear protection is real or just apparent because they're
harder to see in front.

Oops! Enlarged, Magne seems to have a leading front tongue-style thorn
catcher (as opposed to his obvious rear wire model):

http://i17.tinypic.com/80vn3g5.jpg

At least I can't think what else it could be. I mistook it for the
solid metal of the caliper brake on the far side of the tire, but it's
much too high above the rim and a little daylight can be seen between
it and the tire.

Cheers,

Carl Fogel

I think the greatest marvel here is how many of these riders are
carrying tire pumps, something which I thought the (even then)
ubiquitous team cars would have made unnecessary.

--
Ryan Cousineau [email hidden] http://www.wiredcola.com/
"My scenarios may give the impression I could be an excellent crook.
Not true - I am a talented lawyer." - Sandy in rec.bicycles.racing

Quoted message said:

Quoted message said:

Quoted message said:

A 1934 all-wire rear-tire saver, trailing for a change:
http://www.wooljersey.com/gallery/v/aldoross/pd/back_brake_1934.jpg.html
Here's where that photo came from:
http://www.wooljersey.com/gallery/v/aldoross/pd/Magne34.JPG.html?g2_imageView
sIndex=1
See what I mean about huge and gorgeous pictures? No front thorn
catcher for the 1934 TDF winner Antonin Magne, but I'm not sure if the
prevalence of rear protection is real or just apparent because they're
harder to see in front.

Quoted message said:

Quoted message said:

Oops! Enlarged, Magne seems to have a leading front tongue-style thorn
catcher (as opposed to his obvious rear wire model):
http://i17.tinypic.com/80vn3g5.jpg
At least I can't think what else it could be. I mistook it for the
solid metal of the caliper brake on the far side of the tire, but it's
much too high above the rim and a little daylight can be seen between
it and the tire.

Ryan Cousineau said:

I think the greatest marvel here is how many of these riders are
carrying tire pumps, something which I thought the (even then)
ubiquitous team cars would have made unnecessary.

TdF support rules started as "no help whatsoever" and slowly changed to
full support by degrees.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

On Sun, 23 Dec 2007 23:17:47 GMT, Ryan Cousineau <[email hidden]>

Quoted message said:

I think the greatest marvel here is how many of these riders are
carrying tire pumps, something which I thought the (even then)
ubiquitous team cars would have made unnecessary.

Dear Ryan,

Pumps are necessary when Henri Desgrange makes the TDF rules.

Here's Romain Maes, 1935 TDF winner, showing how much the riders liked
the rule:
http://i9.tinypic.com/6wmlv2d.jpg

In the early Tour de France (as opposed to other races of that era),
Desgrange insisted on all sorts of odd rules--for example, you had to
finish the day with the _sweater_ that you carried at the start, not
to mention any punctured tires. (There were lots of strange loopholes,
and the rules changed every year, even from stage to stage.)

In earlier Tours you had to repair things unassisted, so there were
riders who carried their bikes into blacksmith shops and did some
welding, with a judge watching to determine time penalties if a kid
pumped the bellows for you--see long quotes below.

Anyway, that's why you see TDF riders pumping and fixing flats. With
the rules, they had to carry spare tubulars bandolier-fashion and
their pumps in every position--down tube, top tube, and front or back
of seat tube.

The text of this picture dismisses the claim that one rider strapped
his broken bike to his back and finished on a borrowed bike, but the
point is that such things happened--you had to show your broken bike
to the officials.
http://www.wooljersey.com/gallery/v/aldoross/pd/Fontan29.JPG.html

Again, see long quotes below for details of carrying broken wheels.

Oops! Pardon the interruption, but here's a hard-to-see pair of
thorn-catchers from 1935 that just caught my eye:

http://www.wooljersey.com/gallery/v/aldoross/pd/Chocque_1935.jpg.html?g2_imageViewsIndex=1

With the TDF rules about fixing your own flats, riders had a strong
incentive to avoid flats in the first place, whether the flint
catchers worked or not. Maybe the disappearance of the tire savers was
prompted by rule changes that allowed quick wheel swaps?

We now return to our regularly scheduled show about why the TDF riders
carried pumps and tires . . . .

Looser rules in other races allowed wheel swaps, but remember that old
cars weren't quite as fast or maneuverable, that the narrower roads
were blocked by annoying spectators, that there was no radio contact,
and so forth:

http://www.wooljersey.com/gallery/v/aldoross/pd/1937_Crit_National.jpg.html

In other words, the support car might be a long ways off. You don't
see riders running down the road, dragging their bikes to support cars
in modern races!

Even in races like the 1938 Bordeaxu-Paris that allowed wheel swaps,
the cars weren't exactly modern support vans:
http://www.wooljersey.com/gallery/v/aldoross/pd/BPHelyett.JPG.html

More early TDF riders enjoying the rule about fixing their own flats:

1939 TDF--notice the open touring car happily driving away:

http://www.wooljersey.com/gallery/v/aldoross/pd/viettocreve39.jpg.html

1939 TDF again:

http://www.wooljersey.com/gallery/v/aldoross/pd/VissersCreve39.jpg.html

1948 TDF, Robic fixes his own tire:
http://www.wooljersey.com/gallery/v/aldoross/pd/Robic_1948.jpg.html

And so on.

Some details about early TDF repair rules:

"1923. Tour founder Henri Desgrange had established a large, complex
set of rules with the intention of making the Tour a test of the
individual rider and his machine. 1922's problems caused him to
reconsider one rule. Up until 1923 a rider had to perform his own
repairs. Think back to the tragedy of Eugène Christophe and his
multiple broken forks. In 1922 Thys won 5 stages yet finished in
fourteenth place because of a broken wheel in the Pyrenees. Heusghem
was leading the Tour when he hit a pothole, relegating him to fourth
place. In 1923 the rules were changed to allow riders to swap parts
instead of repairing them. This is a monumental change in the
character of the Tour de France. Before, bad luck reigned as the
supreme arbiter of the race. Now, perhaps the race might be more of a
test of the athletic prowess of the riders."

"That didn't mean the other regulatory burdens were relaxed. A rider
still had to finish with everything he had at the start. That included
clothes and spare tires. A flatted tubular had to be transported to
the end of the stage. The rider had to carry the warm clothing he
needed for the early morning starts on the terribly long stages of
those early days to the end of the stage and not discard it. These
rules set the stage for a series of disputes with one of the Tour's
most headstrong riders. The immovable object, Desgrange, again met
Henri Pélissier, the unstoppable force. Before proceeding with the
story of the 1923 Tour let's pause a moment and learn a little bit
about the Pélissiers."

http://www.bikeraceinfo.com/tdf/tdfhistory.html

The blacksmith story:

"Upon arriving in the town he [Christophe carrying a broken frame for
miles in the 1913 TDF] met a little girl who took him to the
blacksmith, a Monsieur Lecomte. Christophe explained his situation to
Lecomte. Lecomte let Christophe use his forge to repair his fork.
Christophe was not only a good bicycle mechanic, he had ben a
locksmith and had metalworking skills. He knew enough to ask for a 22
millimeter diameter tube to make the repair. The blacksmith gave
Christophe some verbal guidance. Under the rules, that was all that
could be allowed."

"Christophe ran out of hands. He not only needed both hands to repair
the fork, someone had to work the bellows to keep the flames high and
hot. Realizing that he had no choice, and wworking under the watchful
eye of Desgrange's commissars and representatives of competing teams
who wanted to make sure that this dangerman followed the rules, he
allowed a boy named Corni to work the bellows . . ."

"As he left the blacksmith's shop one of Desgrange's officials stopped
him. Christophe was given a 10-minute penalty because the little
7-year old boy had helped him with his repair by working the bellows.
The penalty was later reduced to 3 minutes. . . . Christophe still
managed to beat 15 other riders."

--p. 43 "Story of the Tour de France"

The broken wheel story:

"Well into the day's 433 kilometers [stage 14 TDF 1921 was 268 miles
long], Scieur's rear wheel failed with 11 broken spokes. Tour rules of
that time said that if the mechanical failure is real and no repair is
possible a rider may replace the broken item. When Scieur's wheel
broke there were no Tour monitors around to verify his problem. After
replacing the wheel he strapped the broken wheel to his back and
carried it for 300 kilometers to show the officials at the finish that
his need was real. Scars left on his back by the sprocket remained
with him for years."

--p. 61 "Story of the Tour de France"

Cheers,

Carl Fogel

<[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Quoted message said:

A 1934 all-wire rear-tire saver, trailing for a change:

http://www.wooljersey.com/gallery/v/aldoross/pd/back_brake_1934.jpg.html

Quoted message said:

Here's where that photo came from:

http://www.wooljersey.com/gallery/v/aldoross/pd/Magne34.JPG.html?g2_image

ViewsIndex=1

Quoted message said:

Quoted message said:

See what I mean about huge and gorgeous pictures? No front thorn
catcher for the 1934 TDF winner Antonin Magne, but I'm not sure if the
prevalence of rear protection is real or just apparent because they're
harder to see in front.

Oops! Enlarged, Magne seems to have a leading front tongue-style thorn
catcher (as opposed to his obvious rear wire model):

http://i17.tinypic.com/80vn3g5.jpg

At least I can't think what else it could be. I mistook it for the
solid metal of the caliper brake on the far side of the tire, but it's
much too high above the rim and a little daylight can be seen between
it and the tire.

Cheers,

Carl Fogel

A lot of people in this NG have never experienced the scourge of
goatheads. My first encounter was walking across a lawn barefoot in
Albuquerque, New Mexico! The people watching me shrieked in horror as I
picked up 27 goatheads in my bare feet!

http://www.sdc.org/fattire/goatheads.html

A pox on Jobst the Denier " Goatheads don't exit, never existed, can never
exist"

Chas.

In article <[email hidden]>,

A Muzi said:

Quoted message said:

Quoted message said:

[email hidden] wrote:
> A 1934 all-wire rear-tire saver, trailing for a change:
> http://www.wooljersey.com/gallery/v/aldoross/pd/back_brake_1934.jpg.html
> Here's where that photo came from:
> http://www.wooljersey.com/gallery/v/aldoross/pd/Magne34.JPG.html?g2_imageV
> iew
> sIndex=1
> See what I mean about huge and gorgeous pictures? No front thorn
> catcher for the 1934 TDF winner Antonin Magne, but I'm not sure if the
> prevalence of rear protection is real or just apparent because they're
> harder to see in front.

Quoted message said:

Quoted message said:

Oops! Enlarged, Magne seems to have a leading front tongue-style thorn
catcher (as opposed to his obvious rear wire model):
http://i17.tinypic.com/80vn3g5.jpg
At least I can't think what else it could be. I mistook it for the
solid metal of the caliper brake on the far side of the tire, but it's
much too high above the rim and a little daylight can be seen between
it and the tire.

Ryan Cousineau said:

I think the greatest marvel here is how many of these riders are
carrying tire pumps, something which I thought the (even then)
ubiquitous team cars would have made unnecessary.

TdF support rules started as "no help whatsoever" and slowly changed to
full support by degrees.

I forgot how long it took.

--
Ryan Cousineau [email hidden] http://www.wiredcola.com/
"My scenarios may give the impression I could be an excellent crook.
Not true - I am a talented lawyer." - Sandy in rec.bicycles.racing

* * Chas said:

<[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Quoted message said:

A 1934 all-wire rear-tire saver, trailing for a change:

http://www.wooljersey.com/gallery/v/aldoross/pd/back_brake_1934.jpg.html

Quoted message said:

Here's where that photo came from:

http://www.wooljersey.com/gallery/v/aldoross/pd/Magne34.JPG.html?g2_image

ViewsIndex=1

Quoted message said:

Quoted message said:

See what I mean about huge and gorgeous pictures? No front thorn
catcher for the 1934 TDF winner Antonin Magne, but I'm not sure if the
prevalence of rear protection is real or just apparent because they're
harder to see in front.

Oops! Enlarged, Magne seems to have a leading front tongue-style thorn
catcher (as opposed to his obvious rear wire model):

http://i17.tinypic.com/80vn3g5.jpg

At least I can't think what else it could be. I mistook it for the
solid metal of the caliper brake on the far side of the tire, but it's
much too high above the rim and a little daylight can be seen between
it and the tire.

Cheers,

Carl Fogel

A lot of people in this NG have never experienced the scourge of
goatheads. My first encounter was walking across a lawn barefoot in
Albuquerque, New Mexico! The people watching me shrieked in horror as I
picked up 27 goatheads in my bare feet!

http://www.sdc.org/fattire/goatheads.html

A pox on Jobst the Denier " Goatheads don't exit, never existed, can never
exist"

Chas.

Dear Chas,

And a lot of TDF riders never hit goatheads, either--I don't think
that they're too common in France. Botanists think that the goathead
originated in dry, sunny parts of Yugoslavia.

Jobst believes that goatheads exist--he sees them in California. He
just thinks that they can be avoided through sharp-eyed vigilance.

He's partly right. You can certainly see _some_ goathead vines if
they're flowering and not obscured by other plants. And you might be
able to swerve away from them (traffic and road width permitting).

But it's nonsense to argue that riders are routinely spotting and
avoiding individual goatheads on ordinary pavement at 20 mph. I have
ample opportunities, but I've never swerved to avoid one yet. Missing
individual goatheads is just a matter of luck.

And luck runs out fairly quickly where goatheads are ubiquitous.

If a rider's potential path is 8-feet wide (~100 inches) and his tires
sweep a ~1-inch track, the odds are even that he'll hit a goathead if
there are 50 random goatheads strewn on his ride.

It doesn't matter whether the ride is short (just down to the corner)
or long (a double century). All that matters is how many random
goatheads are lying in wait beacuse each random goathead on the
~100-inch potential path provides a 1-in-100 chance that a ~1-inch
tire will run over it.

I suspect that there are at least 3 random goatheads per mile on my
daily 15-mile ride, but I don't flat every other day. This year, I
flat a little more than once a week. Several things lower my flat
rate:

A) Slime tubes seal a lot of punctures. When a tube finally goes flat,
I sometimes apply several patches.

B) Not every goathead pierces the inner tube. They have only two
spines, so you can run over them without getting stuck. When you pick
up a dozen in a sandal, there are a dozen left on the ground. And the
spines can go in at an angle or be too short, leaving the tube intact.
I dig lots of goatheads out of my tread that never touched my inner
tube.

C) I stay away from the edges of the paths and roads as much as I can,
which means that I'm avoiding the zone where the number of random
goatheads rises.

Random variation plays a large role in whether you get a flat. The
same random variation explains why some people think that they can
beat the house in Las Vegas--so far, they really are ahead of the
game. But they tend to attribute their success to whatever system
they're using instead of simple luck.

I suspect that this explains why people sincerely believe that their
skill or their tire-savers are protecting them from the goathead flats
that other riders complain about. They really do have fewer flats, but
they're just lucky. Statistically, their experience is not really
significant.

To illustrate luck and random variation, I've had 54 flats so far in
2007 in 313 15-mile rides.

In 2005, I had only 14 flats on the same route, a 75% reduction.

My comparatively flat-free 2005 years was certainly not due to the
rider paying more attention and avoiding flats. Maybe there were fewer
goatheads that year, but most likely it was just the kind of ordinary
random variation that leads to so many confusing epidemiolgy studies.
With a small enough sample and the right period, almost anything will
happen.

Even doctors will make the mistake of confusing luck and random
variation with whatever strikes their fancy.

A few years ago, a small town in Montana passed a no-smoking law for
restaurants, noted a wonderful drop in heart attacks, and mistakenly
credited the reduction in passive smoking for the huge improvement in
cardiac health, despite such obvious objections as the fact that no
heart attacks had occurred in the restaurants, that many restaurants
had already been effectively smoke free, that the study did not
distinguish between smokers and non-smokers, and so on.

Embarrassingly, skeptics looked at more data and found an even bigger
drop in heart attacks had occurred a few years earlier, before the law
was passed, apparently just a normal fluctuation in the number of rare
events in large populations.

Cheers,

Carl Fogel

Quoted message said:

In the early Tour de France (as opposed to other races of that era),
Desgrange insisted on all sorts of odd rules--for example, you had to
finish the day with the _sweater_ that you carried at the start, not
to mention any punctured tires. (There were lots of strange loopholes,
and the rules changed every year, even from stage to stage.)

In earlier Tours you had to repair things unassisted, so there were
riders who carried their bikes into blacksmith shops and did some
welding, with a judge watching to determine time penalties if a kid
pumped the bellows for you--see long quotes below.

Anyway, that's why you see TDF riders pumping and fixing flats. With
the rules, they had to carry spare tubulars bandolier-fashion and
their pumps in every position--down tube, top tube, and front or back
of seat tube.

The text of this picture dismisses the claim that one rider strapped
his broken bike to his back and finished on a borrowed bike, but the
point is that such things happened--you had to show your broken bike
to the officials.
http://www.wooljersey.com/gallery/v/aldoross/pd/Fontan29.JPG.html

When men were men!

still just me said:

Quoted message said:

In the early Tour de France (as opposed to other races of that era),
Desgrange insisted on all sorts of odd rules--for example, you had to
finish the day with the _sweater_ that you carried at the start, not
to mention any punctured tires. (There were lots of strange loopholes,
and the rules changed every year, even from stage to stage.)

In earlier Tours you had to repair things unassisted, so there were
riders who carried their bikes into blacksmith shops and did some
welding, with a judge watching to determine time penalties if a kid
pumped the bellows for you--see long quotes below.

Anyway, that's why you see TDF riders pumping and fixing flats. With
the rules, they had to carry spare tubulars bandolier-fashion and
their pumps in every position--down tube, top tube, and front or back
of seat tube.

The text of this picture dismisses the claim that one rider strapped
his broken bike to his back and finished on a borrowed bike, but the
point is that such things happened--you had to show your broken bike
to the officials.
http://www.wooljersey.com/gallery/v/aldoross/pd/Fontan29.JPG.html

When men were men!

Dear S,

Real men were still riding the TDF as late as 1962:

http://www.wooljersey.com/gallery/v/aldoross/pd/Altig.JPG.html?g2_imageViewsIndex=1

Cheers,

Carl Fogel

Quoted message said:

Quoted message said:

When men were men!

Dear S,

Real men were still riding the TDF as late as 1962:

http://www.wooljersey.com/gallery/v/aldoross/pd/Altig.JPG.html?g2_imageViewsIndex=1

Cheers,

Carl Fogel

Now that's what I call "Fortitude". None of these wimpy team supported
prima-donnas.

Quoted message said:

On Mon, 24 Dec 2007 03:56:14 GMT, still just me

Quoted message said:

On Sun, 23 Dec 2007 17:56:23 -0700, [email hidden] wrote:

Quoted message said:

Quoted message said:

In the early Tour de France (as opposed to other races of that era),
Desgrange insisted on all sorts of odd rules--for example, you had to
finish the day with the _sweater_ that you carried at the start, not
to mention any punctured tires. (There were lots of strange loopholes,
and the rules changed every year, even from stage to stage.)

Quoted message said:

Quoted message said:

In earlier Tours you had to repair things unassisted, so there were
riders who carried their bikes into blacksmith shops and did some
welding, with a judge watching to determine time penalties if a kid
pumped the bellows for you--see long quotes below.

Quoted message said:

Quoted message said:

Anyway, that's why you see TDF riders pumping and fixing flats. With
the rules, they had to carry spare tubulars bandolier-fashion and
their pumps in every position--down tube, top tube, and front or back
of seat tube.

Quoted message said:

Quoted message said:

The text of this picture dismisses the claim that one rider strapped
his broken bike to his back and finished on a borrowed bike, but the
point is that such things happened--you had to show your broken bike
to the officials.
http://www.wooljersey.com/gallery/v/aldoross/pd/Fontan29.JPG.html

Quoted message said:

When men were men!

Dear S,

Real men were still riding the TDF as late as 1962:

http://www.wooljersey.com/gallery/v/aldoross/pd/Altig.JPG.html?g2_ima...

Cannondale "Lefty?" Hah. There's nothing new under the sun.

- Frank Krygowski

Quoted message said:

To illustrate luck and random variation, I've had 54 flats so far in
2007 in 313 15-mile rides.

In 2005, I had only 14 flats on the same route, a 75% reduction.

My comparatively flat-free 2005 years was certainly not due to the
rider paying more attention and avoiding flats. Maybe there were fewer
goatheads that year, but most likely it was just the kind of ordinary
random variation that leads to so many confusing epidemiolgy studies.

If the route and mileage were the same both years, and we assume that the
flats are randomly distributed with the same probability each year of flat per
mile, then the best estimate of the standard deviation in the number of flats
is:

sigma = square root (54+14) = 8.25,

and the observed difference of 54-14 = 40 flats is thus 4.85 sigma away from
zero. The probability of this great a difference happening by chance is very
small (less than one in a million). So I would conclude that the difference
is indeed significant, and that there is something real that changed between
2005 and 2007.

Carl Fogel said:

To illustrate luck and random variation, I've had 54 flats so far in
2007 in 313 15-mile rides.

In 2005, I had only 14 flats on the same route, a 75% reduction.

Have you considered using Schwalbe Marathon Plus tires? If you can
persuade them to fit in your bike (they come in sizes from 700x28 on
up), I suspect that they'd render such numerous flats a historical
curiosity-- and you love historical curiosities. They are simply
thicker than the length of goathead thorns, and their urethane rubber
filling is better than tread rubber at spitting foreign objects back
out.

Chalo

Clarification: 8.25 is the sigma for the difference in the number of flats
between two different years. Sigma for the number of flats in an individual
year would be this divided by square root of two, about 5.83. Conclusion is
unchanged.

Quoted message said:

Quoted message said:

To illustrate luck and random variation, I've had 54 flats so far in
2007 in 313 15-mile rides.

In 2005, I had only 14 flats on the same route, a 75% reduction.

My comparatively flat-free 2005 years was certainly not due to the
rider paying more attention and avoiding flats. Maybe there were fewer
goatheads that year, but most likely it was just the kind of ordinary
random variation that leads to so many confusing epidemiolgy studies.

If the route and mileage were the same both years, and we assume that the
flats are randomly distributed with the same probability each year of flat
per mile, then the best estimate of the standard deviation in the number of
flats is:

sigma = square root (54+14) = 8.25,

and the observed difference of 54-14 = 40 flats is thus 4.85 sigma away from
zero. The probability of this great a difference happening by chance is
very small (less than one in a million). So I would conclude that the
difference is indeed significant, and that there is something real that
changed between 2005 and 2007.

Chalo said:

Carl Fogel said:

To illustrate luck and random variation, I've had 54 flats so far in
2007 in 313 15-mile rides.

In 2005, I had only 14 flats on the same route, a 75% reduction.

Have you considered using Schwalbe Marathon Plus tires? If you can
persuade them to fit in your bike (they come in sizes from 700x28 on
up), I suspect that they'd render such numerous flats a historical
curiosity-- and you love historical curiosities. They are simply
thicker than the length of goathead thorns, and their urethane rubber
filling is better than tread rubber at spitting foreign objects back
out.

Chalo

Dear Chalo,

Regrettably, there's barely brake clearance for 700x26 on my bike.

In any case, the various allegedly thorn-proof solutions have a
tendency to roll like poorly stuffed mattresses. Armored tires might
be better, but the speed difference between Mr. Tuffy strips and Slime
tubes was marked enough that I'd hate to go back, since I love seeing
my speedometer reach its historical levels, something that happens
less often than I'd like these days.

A common solution around here is to run knobby MTB tires with thorn
resistant tubes on the roads, since no goathead thorn can reach the
inner tube through the knob that touches the pavement.

But the goatheads somehow manage to pierce a lot of MTB tires and
thorn-resistant tubes anyway, going between the knobs or through the
sidewalls. Every summer, I see people pushing knobby-tired bikes along
the roads and bike paths, tires flat as pancakes.

As this page suggests, flats are just part of life where goatheads are
common:

"This region has lots of things with thorns: the worst are the
prickly-pear cacti, mesquite bushes (yep, like the flavoring), and the
bane of the inflatable bicycle tire--goatheads. Any one of these can
end a ride faster than you can say 'What's that noise?'"

"The best defense is the use of heavy duty tubes, tire liners, or tire
sealant. Each of these will add a little extra weight, and may change
the dynamics of your wheels and tires, but they are well worth
having."

"Be warned: Even using all of the above cures at the same time is not
always enough! You should still carry patch kits (check that your glue
hasn't dried out), extra tubes, and pumps."
http://www.sdc.org/fattire/tips-and-tricks.html

Cheers,

Carl Fogel

Barry said:

Clarification: 8.25 is the sigma for the difference in the number of flats
between two different years. Sigma for the number of flats in an individual
year would be this divided by square root of two, about 5.83. Conclusion is
unchanged.

Quoted message said:

Quoted message said:

To illustrate luck and random variation, I've had 54 flats so far in
2007 in 313 15-mile rides.

In 2005, I had only 14 flats on the same route, a 75% reduction.

My comparatively flat-free 2005 years was certainly not due to the
rider paying more attention and avoiding flats. Maybe there were fewer
goatheads that year, but most likely it was just the kind of ordinary
random variation that leads to so many confusing epidemiolgy studies.

If the route and mileage were the same both years, and we assume that the
flats are randomly distributed with the same probability each year of flat
per mile, then the best estimate of the standard deviation in the number of
flats is:

sigma = square root (54+14) = 8.25,

and the observed difference of 54-14 = 40 flats is thus 4.85 sigma away from
zero. The probability of this great a difference happening by chance is
very small (less than one in a million). So I would conclude that the
difference is indeed significant, and that there is something real that
changed between 2005 and 2007.

Dear Barry,

In terms of pure statistical significance, you're probably right.

But in terms of practical variation in a real-world epidemiological
study, varying from 14 to 54 would be barely at the level of
significance.

A relative risk factor of 3 is as low as a credible journal will
accept for case-control studies--and with the yearly average around
30, it wouldn't be accepted.

That is, all sorts of factors might affect the number of flats per
year for ~330 15-mile rides. Reduction might be due to fewer goatheads
growing, heavy early snow melting quickly and washing them off, a
budget cut preventing the highway crew from mowing as far out and
throwing as many thorns onto the road, and so on.

It could also be harder-to-see differences. A run of punctures sealed
by Slime will not be seen, even though each one was a puncture. Flats
are more common in the rain from other debris, so whether I happened
to trust the weatherman and ended up splashing home a little more
often will affect such things. More bicycles and pedestrians could
have swept the path and road clean (or dragged more goatheads out
where I hit them).

In any case, my point is that the difference between 14 punctures in
2005 and 54 punctures so far in 2007 is not likely due to any apparent
change in vigilance on the part of the rider--I've never swerved
around a solitary goathead yet.

As epidemiologists point out, it's very easy to see imaginary trends
when studying extremely rare events in extremely large populations.
I'd love to claim that my skillful riding limited my flat tires in
2005, but I can't imagine anyone who'd believe me.

In fact, I still find it hard to believe that I had no flat tires this
year from July 29th to September 4th, the height of the goathead
season, a streak that Joe DiMaggio would envy--not a single flat
riding every day in August. It's all the more amazing because overall
this has been my worst year this century.

[Modest cough.]

For fun, here's a few years worth of flats and rides, showing the
year-to-year variation:

rides/
front rear total rides flat
2000 18 15 33 349 10.6
2001 16 13 29 339 11.7
2002 36 17 53 343 6.5
2003 16 9 25 351 14.0
2004 17 12 29 352 12.1
2005 8 6 14 339 24.2
2006 16 9 25 340 13.6
2007 36 18 54 313* 5.8
--- --- --- ---
163 99 262 2726 10.4

*I missed 26 rides in the first 46 days of 2007, due to a bad winter
that turned the counties to the east into a national disaster area,
littered with tens of thousands of dead cattle. I should get a few
more rides in before New Year's Eve, preferably without more flats.

Cheers,

Carl Fogel

"Chalo" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Carl Fogel said:

To illustrate luck and random variation, I've had 54 flats so far in
2007 in 313 15-mile rides.

In 2005, I had only 14 flats on the same route, a 75% reduction.

Have you considered using Schwalbe Marathon Plus tires? If you can
persuade them to fit in your bike (they come in sizes from 700x28 on
up), I suspect that they'd render such numerous flats a historical
curiosity-- and you love historical curiosities. They are simply
thicker than the length of goathead thorns, and their urethane rubber
filling is better than tread rubber at spitting foreign objects back
out.

Chalo

I put a set on a friend's bike so I'd never have to fix a flat for her
again. ;-)

They're very difficult to mount because they're so stiff. The tread and
sidewalls feel like they are made of some high durometer urethane rather
than rubber. I've had an easier time mounting 24.5" tubeless truck tires!

Chas.

<[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Chalo said:

Carl Fogel said:

To illustrate luck and random variation, I've had 54 flats so far in
2007 in 313 15-mile rides.

In 2005, I had only 14 flats on the same route, a 75% reduction.

Have you considered using Schwalbe Marathon Plus tires? If you can
persuade them to fit in your bike (they come in sizes from 700x28 on
up), I suspect that they'd render such numerous flats a historical
curiosity-- and you love historical curiosities. They are simply
thicker than the length of goathead thorns, and their urethane rubber
filling is better than tread rubber at spitting foreign objects back
out.

Chalo

Dear Chalo,

Regrettably, there's barely brake clearance for 700x26 on my bike.

In any case, the various allegedly thorn-proof solutions have a
tendency to roll like poorly stuffed mattresses. Armored tires might
be better, but the speed difference between Mr. Tuffy strips and Slime
tubes was marked enough that I'd hate to go back, since I love seeing
my speedometer reach its historical levels, something that happens
less often than I'd like these days.

A common solution around here is to run knobby MTB tires with thorn
resistant tubes on the roads, since no goathead thorn can reach the
inner tube through the knob that touches the pavement.

But the goatheads somehow manage to pierce a lot of MTB tires and
thorn-resistant tubes anyway, going between the knobs or through the
sidewalls. Every summer, I see people pushing knobby-tired bikes along
the roads and bike paths, tires flat as pancakes.

As this page suggests, flats are just part of life where goatheads are
common:

"This region has lots of things with thorns: the worst are the
prickly-pear cacti, mesquite bushes (yep, like the flavoring), and the
bane of the inflatable bicycle tire--goatheads. Any one of these can
end a ride faster than you can say 'What's that noise?'"

"The best defense is the use of heavy duty tubes, tire liners, or tire
sealant. Each of these will add a little extra weight, and may change
the dynamics of your wheels and tires, but they are well worth
having."

"Be warned: Even using all of the above cures at the same time is not
always enough! You should still carry patch kits (check that your glue
hasn't dried out), extra tubes, and pumps."
http://www.sdc.org/fattire/tips-and-tricks.html

Cheers,

Carl Fogel

Carl, Folks who have never experienced the SCOURGE just don't understand.
I once saw a car in Albuquerque that got a flat from goatheads. Albeit
the tire was beyond bald and the casing cords were worn through but the
goatheads had punctured through 1/4" of rubber!

Chas.

* * Chas said:

"Chalo" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Carl Fogel said:

To illustrate luck and random variation, I've had 54 flats so far in
2007 in 313 15-mile rides.

In 2005, I had only 14 flats on the same route, a 75% reduction.

Have you considered using Schwalbe Marathon Plus tires? If you can
persuade them to fit in your bike (they come in sizes from 700x28 on
up), I suspect that they'd render such numerous flats a historical
curiosity-- and you love historical curiosities. They are simply
thicker than the length of goathead thorns, and their urethane rubber
filling is better than tread rubber at spitting foreign objects back
out.

Chalo

I put a set on a friend's bike so I'd never have to fix a flat for her
again. ;-)

They're very difficult to mount because they're so stiff. The tread and
sidewalls feel like they are made of some high durometer urethane rather
than rubber. I've had an easier time mounting 24.5" tubeless truck tires!

Chas.

I use the following...and yes I already know that it's overkill....

Kevlar tires, Mr. Tuffy liners, and Slime. We have those darned
goatheads here too and this has helped to cut WAY back on the amount
of flats that I have experienced.