Goatheads for Jobst

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On Thu, 21 Sep 2006 09:42:36 -0400, dvt <[email protected]> wrote:

>[email protected] wrote:
>> As this picture indicates, you need a combined tire and tube thickness
>> of about 4-5 mm to stop a determined goathead:
>>
>> http://www.filelodge.com/files/room19/497501/184a goathead through mrtuffy.jpg
>> or http://tinyurl.com/jdqhc
>
>Your needle looks a bit dull. But your point is well taken; the goathead
>is sharp enough to penetrate most fabrics.
>
>> Thicker tires and tubes should stop more goatheads, but I suspect that
>> the increase in rolling resistance would also be impressive.
>>
>> When I gave up using thin Mr. Tuffy tire liners like the one in the
>> picture, the speed increase on my daily ride was so marked that I
>> never thought about going back.
>
>Ay, there's the rub. I've never had occasion to try kevlar belts, Mr.
>Tuffy, or any of that stuff. But I've had slow rolling tyres (ever
>ridden a studded snow tyre?), and I know how it feels.
>
>Still, if I had your track record of flats and misfit tyres, I'd be
>willing to lose a minute or so per hour if the other problems improved.
>As usual, YMMV.

Dear Dave,

Alas, the average speed difference between Mr. Tuffy liners and Slime
was around 3 minutes per 15-mile ride, dropping from around 50 minutes
to under 47 minutes.

I didn't know it at the time, but that slow-down is about what this
speed calculator predicts if you double the rolling resistance:

http://w3.iac.net/~curta/bp/velocityN/velocity.html

With 200 watts and 24.2 km, it predicts 45.54 minutes at 31.9 kmh.
Raise the rolling resistance from 0.0050 to 0.0100, and it predicts
49.44 minutes at 29.4 kmh.

I also didn't know that putting in two Mr. Tuffy tire liners was not
likely to reduce flats because the goatheads were going through the
sides, but that imbecile experiment ended after a single ride--the
rolling resistance increase was impressive.

Anyway, the 3-minute decrease in perceived-fun-per-ride was more than
I could possibly stand. To justify it, I calculate that at roughly 333
rides per year, the 3-minute daily speed increase gives me an extra
1,000 minutes to fix flat tires.

Of course, I have no idea what a sensible fellow would do.

Cheers,

Carl Fogel

 

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On Thu, 21 Sep 2006 11:09:09 -0700, Dane Buson <[email protected]>
wrote:

>[email protected] wrote:
>> On Wed, 20 Sep 2006 17:41:50 -0700, Dane Buson <[email protected]>
>>>
>>>So, why not use the Marathon Plus Tires? They are not just a *little*
>>>bit thicker, they are much much thicker [1]. Granted, I don't think
>>>their sidewall protection is as rugged, so you'd still get some flats.
>>>But I imagine it would leaps and bounds better than a simple kevlar
>>>belt.
>>>
>>>[1] As in, run-over-thumbtacks-with-impunity thicker.
>>
>> Dear Dane,
>>
>> As this picture indicates, you need a combined tire and tube thickness
>> of about 4-5 mm to stop a determined goathead:
>
>That should be fine then. The Smartguard strip is 5mm by itself, so
>with a guess-timate of 3mm or so for the tread and casing, I'd say a
>total of 8mm. If you had a thornproof tube, that would of course add an
>additional layer of flat protection.
>
>> http://www.filelodge.com/files/room19/497501/184a goathead through mrtuffy.jpg
>> or http://tinyurl.com/jdqhc
>>
>> (It belatedly occured to me that the goathead's damned thorn was
>> probably not blunted at all by going through the Mr. Tuffy plastic.
>> Most likely, the thorn went through the plastic almost undamaged, then
>> went effortlessly through the thin padding of a work mat, and broke
>> its nose only when it hit the wooden bench underneath the mat.)
>>
>> Thicker tires and tubes should stop more goatheads, but I suspect that
>> the increase in rolling resistance would also be impressive.
>
>I haven't noticed much difference in rolling resistance myself, at least
>my averages haven't suffered noticably. I also recently did a descent
>down Hurricane Ridge where my highest previous speed was 43mph. With
>the Schwalbe I hit 45 mph. I was wearing very similar clothing compared
>to the previous time, so my aero drag was probably not too different.
>Not a very controlled test, but it's all I have.
>
>They are noticably heavier, but I don't think that's necessarily a bad
>thing. If someone is really interested in the rolling resistance I
>suppose they could do a drum test or a roll out.

Dear Dane,

I suspect that an 8mm thick tire would more than double the rolling
resistance.

To get an idea of what this could involve, select hands-on-drops near
the top of this speed calculator and plug my 15-mile daily distance
into the trip field near the bottom:

http://www.kreuzotter.de/english/espeed.htm

With the default "narrow racing tires," you get 19.4 mph and 46:23.5.

With "robust wide touring tires," you get 17.9 mph and 50:16.8.

Similarly, set the power and cadence to 0, then tip the road to -8 for
a high-speed 8% downhill. The defaults with narrow tires predict 43.1
mph, while the "robust" tires drop to 38.4 mph.

Unfortunately, you need either a good calculator or else dozens of
repeated rides over the same route to get useful speed results. Wind,
temperature, the details of your tuck, and initial speed will cause
the speed on a downhill to vary much more than most posters realize.

Here's an example of how annoyingly real-life coasting tests can be. I
roll down three hills every day, pedalling up to the same mark,
tucking in, and admiring the speedometer.

This is the last week of data for my maximum speed descending a long,
gentle stretch of highway, along with my overall time for about 15
miles:

max mph time
35.3 43:51
46.5 48:13
38.0 46:08
43.4 46:40
38.5 45:48
38.9 48:35
43.4 45:06

week's week's
avg mph avg time
40.57 46:20

year's year's
avg mph avg time
37.82 48:30

Notice that the maximum speed varied from 35.3 to 46.5 mph. This may
look impressive, but it's really nothing more than a gentle 5 mph
headwind versus a 5 mph tailwind, which is scarcely noticeable (a
brisk walk is about 4 mph--see if you notice the wind on your face as
you stride down a long hallway).

Notice also that the speed on that downhill for last week is almost
10% higher than the average for the year so far. Some of that 2.75 mph
speed increase is random variation, but about 1.6 mph is probably the
pure temperature effect of an 80F week in late summer versus a lot of
40F days.

That's how sensitive bicycle speeds are--that same rider, bike, narrow
tires, and wind profile will go 42.0 mph down that 8% hilll at 40F
instead of 43.6 mph at 80F.

Have a look at this table of rolling resistance:

http://www.legslarry.beerdrinkers.co.uk/tech/JL.htm

Schwalbe Marathons were tested (weird small size, but probably similar
to results for a 700c version). Their RR was around 0.0100, about
double the 0.0050~0.0060 RR for normal narrow tires.

You can see the effect here:

http://w3.iac.net/~curta/bp/velocityN/velocity.html

Reduce the watts to a more modest 200, set the distance to 24.2 km (15
miles), and the calculator predicts that with the default 0.0050 RR,
you'll go 31.9 kmh and take 45.55 minutes.

Raise the RR to 0.0100, and the calculator predicts 49.4 minutes at
29.4 kmh, about the same differeace as the Kreuzotter calculator
predicts for narrow versus robust wide touring tires.

Sadly, thicker, heavier tires bend a lot more rubber as they roll,
which slows things down. At around 3 minutes faster per day for around
330 days per year, my thinner tires give me about 1,000 extra minutes
to change 20 to 50 flat tires per year, so theoretically I'm coming
out ahead (which surprises me).

Cheers,

Carl Fogel

 

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On 13 Sep 2006 21:40:46 -0700, [email protected] wrote:

>[email protected] wrote:
>
> [snip]
>

Hmmm . . . my rear tire feels a bit low to my thumbs.

Attach floor pump, pump on t-handle several times, watch gauge rise to
120 psi, whap valve stem on Slime tube with handy tool handle to
release stuck Presta valve, and--

Gauge drops to 80 psi. My thumbs need recalibration.

Pump to 120 psi. No hissing. Slime must have sealed puncture.

Aha! Right where the tread meets the sidewall is the stub of goathead.

Yank, drop of green Slime appears, but no hissing.

Inflate tube, coil, dunk in sink.

Insert toothpick at bubbles.

And another.

And again.

And one more--annoying, since I grabbed only three toothpicks from the
drawer and need another.

There!

http://www.filelodge.com/files/room19/497501/221 four goatheads in one tube.jpg
or http://tinyurl.com/jzumm

I count these four goathead punctures accumlated in 13 daily rides
from September 20th to October 2nd as a single flat, not four.

Nice that the Slime tube held so well. I bet I could have gotten a few
more rides in.

CF

 

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On 13 Sep 2006 21:40:46 -0700, [email protected] wrote:

>[email protected] wrote:

[snip]

It's been eight days since my last flat, but only seven 15-mile rides
because it rained all day Sunday.

Today, the long, fast downhill on my daily ride felt much too plush. A
peek back down at my rear tire showed that the 700x26 looked more like
a flabby 700x32, so I stopped and replaced the rear tube, which had a
slow leak from a goathead thorn.

I really, really like that new Topeak Road Morph pump.

A glance at my spreadsheet shows 8 flats in my last 44 15-mile rides,
some with more than one Slime-sealed puncture when patched.

CF

 

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On 13 Sep 2006 21:40:46 -0700, [email protected] wrote:

>[email protected] wrote:
>
> [snip]

The goatheads decided to add insult to injury.

This morning, my rear tire was down to 40 psi, so I yanked the tube,
checked the tire, found a goathead thorn, dug it out, put in a new
tube, and dunked the culprit in the sink to find the pinhole.

The bubbles came from where I'd already patched the tube.

Drat! The patch must have failed.

Or so I assumed.

But after I peeled the Rema patch off, I was startled to see two
separate streams of bubbles, one from the original puncture and
another, right at the edge of where the patch had been.

The patch was nicely centered over the original hole. The new hole is
about 3 mm from the edge of the patch, just barely inside the ring of
exposed red material around the edge of the patch.

So a goathead somehow took aim at the patch on my inner tube before
lancing through my tire. Not quite a bullseye, but awfully close.

CF

 

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On 13 Sep 2006 21:40:46 -0700, [email protected] wrote:

>[email protected] wrote:
>
> [snip]

The cracks on the highway shoulder didn't feel quite as harsh as usual
on the way back into town, so I peered down at my front tire, but I
couldn't tell for sure if it was bulging.

When I finally stopped, still looking down, the front tire bulged and
wrinkled visibly.

Sure enough, the stub of a goathead was sticking out of the top of the
left side of the tire. When I pulled the thorn out, a single tear of
green Slime trickled out, followed by a gentle hiss.

A farm dog stood on a small mound and barked helpfully at me over his
fence while I fixed the flat. He probably appreciated the change that
I offered from the deer and skunks that cross nearby.

Once again, I was pleased with my new Topeak Road Morph pump.

With the flat rear tire that I fixed before I left this morning,
that's ten goathead flats in 58 fifteen-mile rides since August 27th.

CF

 

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On 13 Sep 2006 21:40:46 -0700, [email protected] wrote:

>[email protected] wrote:
>
> [snip]

It was such a nice morning that I went out for my usual ride before a
visiting friend arrives for an afternoon ride.

When my front tire went soft, I dug out three goathead thorn tips, but
none of them were responsible--no hiss, no slime, nothing.

As I turned the tire, a tiny drop of green Slime oozed out of an
almost invisible hole in the tread, where a goathead had plunged
through and then withdrawn, unbroken. Sink testing confirmed only the
single pinhole.

That's four goathead flats in seven 15-mile rides, two on the front
and two on the rear. Undoubtedly I should keep a closer eye on the
pavement and avoid them, but spotting goatheads may be a little harder
than the FAQ suggests in places where goatheads are prolific.

(It may even be impossible on my downhill, where a tailwind pushed
the maximum speed reading to 46.5 mph this morning, or 68 feet per
second.)

My friend has never had a flat when he visits. We go for a ride, he
has a pleasant outing, and neither of us gets a flat.

But a week later, I usually notice that one of the tires on the bike
that he uses has gone flat from a slow leak.

CF

 

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On 13 Sep 2006 21:40:46 -0700, [email protected] wrote:

>[email protected] wrote:
>
> [snip]

While I was rebuilding my rear wheel last night, a goathead was
quietly nibbling through my front tire, dead center in the tread.

The Slime held the pressure to 60 psi.

The hard freeze last night killed all the blue morning glories, but
it's almost 70F now. Maybe the chinook wind that's blowing will
somehow turn into a tailwind all the way around my daily loop.

Cheers,

Carl Fogel

 

[[email protected]]

On 13 Sep 2006 21:40:46 -0700, [email protected] wrote:

>[email protected] wrote:
>
> [snip]

This is dangerously close to becoming annoying.

I fixed a slow-leak front flat before my ride this afternoon.

Six minutes out, I thought no, it can't be going flat already.

The damned goathead was still sticking out of the sidewall.

Possibly this creature was kicking goatheads out onto the path:

http://server5.theimagehosting.com/image.php?img=290atarantula.jpg
or http://tinyurl.com/ydrtag

They're busy crossing the path--I've seen one every day for the last
week or so.

CF

 

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On 13 Sep 2006 21:40:46 -0700, [email protected] wrote:

[snip]

A 32-degree temperature drop from yesterday's high, but no snow for a
change on Halloween. Eleven deer paid little attention to me in the
39F weather.

The low rear tire that I pumped up before my ride turned out to be
another goathead flat. Amused myself by digging smaller thorns and
rock chips out of both tires. The front tube had no leak, so back it
went into the tire.

I find that rubbing the patch area with a piece of chalk stops it
from sticking to the inside of the tire.

A friend asked if I used a roller-stitcher to flatten my patches,
since that's what he was taught to do as a motorcycle mechanic.

Of course not, I scoffed in a deep, manly voice, my thumbnail works
just fine.

Furtive internet searching showed that BikeToolsEtc will sell me a
genuine Rema roller-stitcher with ball bearings and wooden handle for
about $14.50, plus shipping:

http://biketoolsetc.com/index.cgi?i...d-Tube&tc=Ball-Bearing-Stitcher&item_id=RE-30
or http://tinyurl.com/yz77zt

For twenty bucks or so, I'd still be using my thumbnail or the knurled
grip of a pair of pliers.

But Checker Auto, a typical chain, had an all-metal Victor/Monkey-Grip
roller-stitcher. It has no ball bearings, so I can't roll it back and
forth quite as fast as the stylish Rema, but the Monkey-Grip model
includes a handsome built-in scraper to roughen the inner tube's
surface. It cost only $1.41 with tax last week, but has now vanished
from the web site.

It worked fine tonight, as far as I can tell, 120 miles after my last
flat.

Cheers,

Carl Fogel

 

[[email protected]]

[email protected] wrote:
>
>
> A friend asked if I used a roller-stitcher to flatten my patches,
> since that's what he was taught to do as a motorcycle mechanic.
>
> Of course not, I scoffed in a deep, manly voice, my thumbnail works
> just fine.

FWIW, I fix punctures at home using a cylindrical work surface - a 1.5"
dowel held in a vise. I drape the tube over the dowel. Seems to make
it easier to buff the tube, etc.

When the cement's dry, I apply the patch, then roll it down with
another cylindrical object, something like a screwdriver shaft, tire
iron, or whatever's handy, held perpendicular to the dowel. This
allows good pressure on the patch.

-

On a related matter: I don't know if this was mentioned recently but:


Carl, have you ever tried the old style "tire savers" or "flint
catchers" - those wire-and-plastic-tubing things intended to scrape
just above the tire's surface, hopefully snagging and dislodging thorns
and such before a second revolution pushes them in?

I know many folks judge them useless, saying that the damage is done
immediately, not on successive revolutions. But ISTM you'd have little
to lose by trying them.

- Frank Krygowski

 

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On 1 Nov 2006 08:09:08 -0800, [email protected] wrote:

>
>[email protected] wrote:
>>
>>
>> A friend asked if I used a roller-stitcher to flatten my patches,
>> since that's what he was taught to do as a motorcycle mechanic.
>>
>> Of course not, I scoffed in a deep, manly voice, my thumbnail works
>> just fine.
>
>FWIW, I fix punctures at home using a cylindrical work surface - a 1.5"
>dowel held in a vise. I drape the tube over the dowel. Seems to make
>it easier to buff the tube, etc.
>
>When the cement's dry, I apply the patch, then roll it down with
>another cylindrical object, something like a screwdriver shaft, tire
>iron, or whatever's handy, held perpendicular to the dowel. This
>allows good pressure on the patch.
>
>-
>
>On a related matter: I don't know if this was mentioned recently but:
>
>Carl, have you ever tried the old style "tire savers" or "flint
>catchers" - those wire-and-plastic-tubing things intended to scrape
>just above the tire's surface, hopefully snagging and dislodging thorns
>and such before a second revolution pushes them in?
>
>I know many folks judge them useless, saying that the damage is done
>immediately, not on successive revolutions. But ISTM you'd have little
>to lose by trying them.
>
>- Frank Krygowski

Dear Frank,

Like you, I use a rounded surface as my tube-patching "workbench".
It's just the handy 4-inch-wide polished round barrel of a big
tilt-and-swivel vise, which holds up to five tubes at once.

As for the flint-catchers, Tony Raven suggests that they can help, at
least with flints in the UK:

http://groups.google.com/group/uk.rec.cycling/msg/c54304dfb1841151
or http://tinyurl.com/y5eox4

But Jobst argues that tire savers make no statistical difference:

"Ah yes, "tire savers", as they were known in some circles, were one
of those "tossing salt over the shoulder" quirks of bicycling, like
wiping tires. Among my riding companions the only thing they did was
to make obvious who had them on their bicycles when the roads were
wet, because the guy with tire savers was the rider with the dirtiest
legs. The number of flats had no apparent statistical difference. The
tire saver guys were there on Wednesday evenings at my weekly tire
patch sessions just like the others."

http://groups.google.com/group/rec.bicycles.tech/msg/1202787bc070229f

Yet elsewhere Jobst claims that there is a huge statistical difference
in the frequency of flats:

"Locally, we have riders who constantly get flats in spite of liners
and slime... and they ride the same routes that I and many others ride
without problem."

http://groups.google.com/group/rec.bicycles.tech/msg/70a2c60abeaa6b58

Since Tony Raven and others have found tire savers to be useful, I'm
looking into them, but no one seems to make tire savers any more.

The tire savers strike me as likely to fail for two reasons.

First, a smooth round wire lightly brushing the tread isn't likely to
yank small chips out of the tire.

If anything, the wire should push the chip in a tiny bit further,
unless quite a bit of the chip is sticking out. The chips that I dig
out of my tires are usually not a lot bigger than a 2mm spoke, so
they'd be poor candidates for tire-saver removal. The UK flints may be
much bigger and easier to snag.

Second, my problem is mostly needle-pointed goatheads, not chips. The
goatheads pretty much bury themselves to the hilt with the first
thrust.

I dig lots of goathead thorn-tips out of my tire that failed to
puncture the inner tube, but what saved me is just that the thorn tips
were just too short to reach the inner tube through the tread, the
casing, and the internal Kevlar belt of my tires.

Cheers,

Carl Fogel

 

[[email protected]]

[email protected] wrote:
>
> Since Tony Raven and others have found tire savers to be useful, I'm
> looking into them, but no one seems to make tire savers any more.

It would be easy to open an old bike parts catalog and copy them. The
ones I had were just bits of wire bent to fit, insulated from the brake
frame by thin plastic tubing.

One problem, I suppose, is that they were typically bolted in place
with the brake mounting bolt, but that was before recessed allen bolts
or nuts. Not an insurmountable problem, though.

>
> The tire savers strike me as likely to fail for two reasons.
>
> First, a smooth round wire lightly brushing the tread isn't likely to
> yank small chips out of the tire.
>
....

>
> Second, my problem is mostly needle-pointed goatheads, not chips. The
> goatheads pretty much bury themselves to the hilt with the first
> thrust...


If I got flats as frequently as you do, I'd try it anyway. There's
little to lose.

When we started cycling in the early 1970s, tire savers were somewhat
popular. My wife had them on her bike, but I usually didn't. She got
noticeably fewer flats than I did, but I rode more, so I can't say much
about the flats per mile rate.

I recall that Rivendell once had an article about using leather thongs
loosely draped across the tire surface as thorn catchers. IIRC, they
were tied to fork blades (front) or seat stays (rear).

My flat count is quite low. (Maybe I need to look at the scenery
more?) But if I had your problem, I'd be experimenting intensely.
Wire? Leather thong? Toothbrush? Snowplow ahead of front wheel?
etc...

- Frank Krygowski

 

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On 1 Nov 2006 12:35:30 -0800, [email protected] wrote:

>
>[email protected] wrote:
>>
>> Since Tony Raven and others have found tire savers to be useful, I'm
>> looking into them, but no one seems to make tire savers any more.
>
>It would be easy to open an old bike parts catalog and copy them. The
>ones I had were just bits of wire bent to fit, insulated from the brake
>frame by thin plastic tubing.
>
>One problem, I suppose, is that they were typically bolted in place
>with the brake mounting bolt, but that was before recessed allen bolts
>or nuts. Not an insurmountable problem, though.
>
>>
>> The tire savers strike me as likely to fail for two reasons.
>>
>> First, a smooth round wire lightly brushing the tread isn't likely to
>> yank small chips out of the tire.
>>
>...
>
>>
>> Second, my problem is mostly needle-pointed goatheads, not chips. The
>> goatheads pretty much bury themselves to the hilt with the first
>> thrust...
>
>
>If I got flats as frequently as you do, I'd try it anyway. There's
>little to lose.
>
>When we started cycling in the early 1970s, tire savers were somewhat
>popular. My wife had them on her bike, but I usually didn't. She got
>noticeably fewer flats than I did, but I rode more, so I can't say much
>about the flats per mile rate.
>
>I recall that Rivendell once had an article about using leather thongs
>loosely draped across the tire surface as thorn catchers. IIRC, they
>were tied to fork blades (front) or seat stays (rear).
>
>My flat count is quite low. (Maybe I need to look at the scenery
>more?) But if I had your problem, I'd be experimenting intensely.
>Wire? Leather thong? Toothbrush? Snowplow ahead of front wheel?
>etc...
>
>- Frank Krygowski

Dear Frank,

Off for the daily experiment, but sadly the problem has been solved.
You run knobby MTB tires, whose knobs are much thicker than the
thorns, add Mr. Tuffy strips and thicker thorn-proof tubes for the
goatheads that sneak in between the knobs, and use Slime.

Unfortunately, the combination reminds you why police and soldiers
often say to hell with it and take off their heavy body armor. The
rolling resistance increases impressively. Just the tire liners added
three minutes to my average time for fifteen miles, which works out to
about a mile at my pace.

If you're used to the goatheads, it's not so bad, as long as you don't
have to read nonsense about "avoiding" them by impossible alertness
and eyesight that would impress an antelope.

As for the snowplow suggestion, I do let my friends ride ahead of me
when they visit, ostensibly so they can enjoy the scenery and not
worry about catching up with me.



Cheers,

Carl Fogel

 

[[email protected]]

Carl Fogel writes:

>>> A friend asked if I used a roller-stitcher to flatten my patches,
>>> since that's what he was taught to do as a motorcycle mechanic.

>>> Of course not, I scoffed in a deep, manly voice, my thumbnail
>>> works just fine.

>> FWIW, I fix punctures at home using a cylindrical work surface - a
>> 1.5" dowel held in a vise. I drape the tube over the dowel. Seems
>> to make it easier to buff the tube, etc.

>> When the cement is dry, I apply the patch, then roll it down with
>> another cylindrical object, something like a screwdriver shaft,
>> tire iron, or whatever's handy, held perpendicular to the dowel.
>> This allows good pressure on the patch.

>> On a related matter: I don't know if this was mentioned recently
>> but:

>> Carl, have you ever tried the old style "tire savers" or "flint
>> catchers" - those wire-and-plastic-tubing things intended to scrape
>> just above the tire's surface, hopefully snagging and dislodging
>> thorns and such before a second revolution pushes them in?

>> I know many folks judge them useless, saying that the damage is
>> done immediately, not on successive revolutions. But ISTM you'd
>> have little to lose by trying them.

> Like you, I use a rounded surface as my tube-patching "workbench".
> It's just the handy 4-inch-wide polished round barrel of a big
> tilt-and-swivel vise, which holds up to five tubes at once.

I believe that you can't get better contact with more pressure than you
can apply with a well place thumb pressing on a table. As I related,
the REMA patch representative at InterBike 2005 rolled on a patch
which I readily pulled off again when he handed it to me. In
contrast, after a curing pause (for me that is the next day) the patch
cannot be pulled off without the frying pan heat treatment.

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

> As for the flint-catchers, Tony Raven suggests that they can help,
> at least with flints in the UK:

http://tinyurl.com/y5eox4

> But Jobst argues that tire savers make no statistical difference:

# Ah yes, "tire savers", as they were known in some circles, were one
# of those "tossing salt over the shoulder" quirks of bicycling, like
# wiping tires. Among my riding companions the only thing they did was
# to make obvious who had them on their bicycles when the roads were
# wet, because the guy with tire savers was the rider with the
# dirtiest legs. The number of flats had no apparent statistical
# difference. The tire saver guys were there on Wednesday evenings at
# my weekly tire patch sessions just like the others.

http://groups.google.com/group/rec.bicycles.tech/msg/1202787bc070229f

> Yet elsewhere Jobst claims that there is a huge statistical
> difference in the frequency of flats:

# Locally, we have riders who constantly get flats in spite of liners
# and slime... and they ride the same routes that I and many others
# ride without problem.

http://groups.google.com/group/rec.bicycles.tech/msg/70a2c60abeaa6b58

> Since Tony Raven and others have found tire savers to be useful, I'm
> looking into them, but no one seems to make tire savers any more.

> The tire savers strike me as likely to fail for two reasons.

> First, a smooth round wire lightly brushing the tread isn't likely
> to yank small chips out of the tire.

> If anything, the wire should push the chip in a tiny bit further,
> unless quite a bit of the chip is sticking out. The chips that I dig
> out of my tires are usually not a lot bigger than a 2mm spoke, so
> they'd be poor candidates for tire-saver removal. The UK flints may
> be much bigger and easier to snag.

The dragging wire is not round but rather is half-round, and it gets
progressively thinner after a few miles. However, it wears through in
not too many miles, especially on damp roads where fine road emery is
carried around to it by the tire.

The reason you can't find them is that they proved demonstrably
ineffective, but then tying and soldering outlived the high wheeler by
nearly a hundred years as a comparison. Of course its benefits
required special test equipment, so the practice remained as long as
those who performed the modification claimed it had unproven benefits.
Who are we to question authority!

> Second, my problem is mostly needle-pointed goatheads, not chips.
> The goatheads pretty much bury themselves to the hilt with the first
> thrust.

That is the event with most anything that will cut tread rubber.

> I dig lots of goathead thorn-tips out of my tire that failed to
> puncture the inner tube, but what saved me is just that the thorn tips
> were just too short to reach the inner tube through the tread, the
> casing, and the internal Kevlar belt of my tires.

Too bad you didn't use an errant goathead for your puncture test
instead of a dull nail. You seem to have an endless supply of these
thorns in your daily life.

Jobst Brandt

 

[[email protected]]

What a weird thread... why am i responding to this?

First off I fortunately do not live in an area with 'goathead'
thorns. Though I am familiar with them from bicycle trips
to NM, and those thorns are indeed wicked.

I've been using these continental tires for the past two
years that have some sort of aramid belt. I can say,
based on my experience, that these new armored tires
are much tougher then the older kevlar belted ones. I've
had them stop several shards of glass, and one large
thorn. The thron had broken off flush with the tire and I was
able to pick it out of the (still inflated) tire. The tip had
broken off at the aramid belt.

So perhaps you will lose a few minutes to rolling resistance...
who cares, sounds like you are wasting for more time
than that fixing flats at this point.

At worse you could use the more clunky tires during the few
months out of the year when the thorns are a problem.
Anyway you seem to be enjoying your thorn ordeal,
in a perverse sort of way. And you're doing a favor to
other cyclists mopping all those pesky thorns up.

All I got to say on this.

Eric

 

[[email protected]]

[email protected] wrote:
> What a weird thread... why am i responding to this?
>
> First off I fortunately do not live in an area with 'goathead'
> thorns. Though I am familiar with them from bicycle trips
> to NM, and those thorns are indeed wicked.
>
> I've been using these continental tires for the past two
> years that have some sort of aramid belt. I can say,
> based on my experience, that these new armored tires
> are much tougher then the older kevlar belted ones. I've
> had them stop several shards of glass, and one large
> thorn. The thron had broken off flush with the tire and I was
> able to pick it out of the (still inflated) tire. The tip had
> broken off at the aramid belt.
>
> So perhaps you will lose a few minutes to rolling resistance...
> who cares, sounds like you are wasting for more time
> than that fixing flats at this point.
>
> At worse you could use the more clunky tires during the few
> months out of the year when the thorns are a problem.
> Anyway you seem to be enjoying your thorn ordeal,
> in a perverse sort of way. And you're doing a favor to
> other cyclists mopping all those pesky thorns up.
>
> All I got to say on this.
>
> Eric

{edit} wanted to add the tires I'm using are slicks,
not thick heavy treaded tires. Get some aramid belted
slicks for your road bike. Nothing to lose but a few $$$,
and perhaps much wasted time fixing flats.

 

[[email protected]]

On 1 Nov 2006 18:59:23 -0800, [email protected] wrote:

>
>[email protected] wrote:
>> What a weird thread... why am i responding to this?
>>
>> First off I fortunately do not live in an area with 'goathead'
>> thorns. Though I am familiar with them from bicycle trips
>> to NM, and those thorns are indeed wicked.
>>
>> I've been using these continental tires for the past two
>> years that have some sort of aramid belt. I can say,
>> based on my experience, that these new armored tires
>> are much tougher then the older kevlar belted ones. I've
>> had them stop several shards of glass, and one large
>> thorn. The thron had broken off flush with the tire and I was
>> able to pick it out of the (still inflated) tire. The tip had
>> broken off at the aramid belt.
>>
>> So perhaps you will lose a few minutes to rolling resistance...
>> who cares, sounds like you are wasting for more time
>> than that fixing flats at this point.
>>
>> At worse you could use the more clunky tires during the few
>> months out of the year when the thorns are a problem.
>> Anyway you seem to be enjoying your thorn ordeal,
>> in a perverse sort of way. And you're doing a favor to
>> other cyclists mopping all those pesky thorns up.
>>
>> All I got to say on this.
>>
>> Eric
>
>{edit} wanted to add the tires I'm using are slicks,
>not thick heavy treaded tires. Get some aramid belted
>slicks for your road bike. Nothing to lose but a few $$$,
>and perhaps much wasted time fixing flats.

Dear Eric,

Alas, my slick tires have Kevlar belts. The aramid fibers offer no
real resistance to the thorns. As Jobst points out, you might as well
expect steel wool to stop a darning needle. Kevlar belts are better at
stopping glass and rock chips.

Kevlar belts do reduce goathead flats to some degree, but the trick is
just that they increase the thickness that the short but evil thorns
must penetrate.

And alas, the thorns are a year-round problem. The hard, nasty little
devils that grow and fall off the flat vines don't vanish just because
it gets cold.

As for the time . . . At 3 minutes per day, I save about a thousand
minutes per year, or about twenty minutes per week, more time than I
spend fixing 25-35 flats per year.

Sadly, short of knobby tires, Mr. Tuffy strips, and thicker tubes,
there's little improvement likely over the flat rate of my
faster-rolling 700x26 tires with Slime tubes.

But I'm looking into the little wire tire-saver loops, spurred on by
Tony and Frank. Unfortunately, tire savers are hard to find, short of
making my own--and the only thing worse than my mechanical skills is
my carpenty.

It's hard to say whether being hard to find is evidence that tire
savers don't work, work but aren't needed by people who hardly ever
have flats, or work on rock chips but not goatheads or glass. The most
emphatic comments on tire savers come from Jobst, who mentions only
6-8 flats per 10,000 miles in a year, 3-4 of them impact flats. That
would be like me having 1-2 flats in my 5,000-mile year, since impact
flats are as rare for me as goatheads are for Jobst.

Glad to hear that goatheads aren't a problem for you.

As for why you're reading the thread, it's because these little
squabbles offer different views of interesting peculiarities and you
can learn something about both bicycles and bicyclists from them. I'm
always curious about rain threads, even though much of the 10-14
inches of water Pueblo gets per years is snow melt and cloudburst.

Cheers,

Carl Fogel

 

[[email protected]]

On 02 Nov 2006 02:11:32 GMT, [email protected] wrote:

>Carl Fogel writes:
>
>>>> A friend asked if I used a roller-stitcher to flatten my patches,
>>>> since that's what he was taught to do as a motorcycle mechanic.
>
>>>> Of course not, I scoffed in a deep, manly voice, my thumbnail
>>>> works just fine.
>
>>> FWIW, I fix punctures at home using a cylindrical work surface - a
>>> 1.5" dowel held in a vise. I drape the tube over the dowel. Seems
>>> to make it easier to buff the tube, etc.
>
>>> When the cement is dry, I apply the patch, then roll it down with
>>> another cylindrical object, something like a screwdriver shaft,
>>> tire iron, or whatever's handy, held perpendicular to the dowel.
>>> This allows good pressure on the patch.
>
>>> On a related matter: I don't know if this was mentioned recently
>>> but:
>
>>> Carl, have you ever tried the old style "tire savers" or "flint
>>> catchers" - those wire-and-plastic-tubing things intended to scrape
>>> just above the tire's surface, hopefully snagging and dislodging
>>> thorns and such before a second revolution pushes them in?
>
>>> I know many folks judge them useless, saying that the damage is
>>> done immediately, not on successive revolutions. But ISTM you'd
>>> have little to lose by trying them.
>
>> Like you, I use a rounded surface as my tube-patching "workbench".
>> It's just the handy 4-inch-wide polished round barrel of a big
>> tilt-and-swivel vise, which holds up to five tubes at once.
>
>I believe that you can't get better contact with more pressure than you
>can apply with a well place thumb pressing on a table. As I related,
>the REMA patch representative at InterBike 2005 rolled on a patch
>which I readily pulled off again when he handed it to me. In
>contrast, after a curing pause (for me that is the next day) the patch
>cannot be pulled off without the frying pan heat treatment.
>
>http://www.sheldonbrown.com/brandt/patching.html
>
>> As for the flint-catchers, Tony Raven suggests that they can help,
>> at least with flints in the UK:
>
> http://tinyurl.com/y5eox4
>
>> But Jobst argues that tire savers make no statistical difference:
>
># Ah yes, "tire savers", as they were known in some circles, were one
># of those "tossing salt over the shoulder" quirks of bicycling, like
># wiping tires. Among my riding companions the only thing they did was
># to make obvious who had them on their bicycles when the roads were
># wet, because the guy with tire savers was the rider with the
># dirtiest legs. The number of flats had no apparent statistical
># difference. The tire saver guys were there on Wednesday evenings at
># my weekly tire patch sessions just like the others.
>
> http://groups.google.com/group/rec.bicycles.tech/msg/1202787bc070229f
>
>> Yet elsewhere Jobst claims that there is a huge statistical
>> difference in the frequency of flats:
>
># Locally, we have riders who constantly get flats in spite of liners
># and slime... and they ride the same routes that I and many others
># ride without problem.
>
> http://groups.google.com/group/rec.bicycles.tech/msg/70a2c60abeaa6b58
>
>> Since Tony Raven and others have found tire savers to be useful, I'm
>> looking into them, but no one seems to make tire savers any more.
>
>> The tire savers strike me as likely to fail for two reasons.
>
>> First, a smooth round wire lightly brushing the tread isn't likely
>> to yank small chips out of the tire.
>
>> If anything, the wire should push the chip in a tiny bit further,
>> unless quite a bit of the chip is sticking out. The chips that I dig
>> out of my tires are usually not a lot bigger than a 2mm spoke, so
>> they'd be poor candidates for tire-saver removal. The UK flints may
>> be much bigger and easier to snag.
>
>The dragging wire is not round but rather is half-round, and it gets
>progressively thinner after a few miles. However, it wears through in
>not too many miles, especially on damp roads where fine road emery is
>carried around to it by the tire.
>
>The reason you can't find them is that they proved demonstrably
>ineffective, but then tying and soldering outlived the high wheeler by
>nearly a hundred years as a comparison. Of course its benefits
>required special test equipment, so the practice remained as long as
>those who performed the modification claimed it had unproven benefits.
>Who are we to question authority!
>
>> Second, my problem is mostly needle-pointed goatheads, not chips.
>> The goatheads pretty much bury themselves to the hilt with the first
>> thrust.
>
>That is the event with most anything that will cut tread rubber.
>
>> I dig lots of goathead thorn-tips out of my tire that failed to
>> puncture the inner tube, but what saved me is just that the thorn tips
>> were just too short to reach the inner tube through the tread, the
>> casing, and the internal Kevlar belt of my tires.
>
>Too bad you didn't use an errant goathead for your puncture test
>instead of a dull nail. You seem to have an endless supply of these
>thorns in your daily life.
>
>Jobst Brandt

Dear Jobst,

The topic for the nail test was rock chips--you know, the kind found
by a few dozen UK posters, despite strange claims that rock chips
can't cause flats.

Alas, I have no ready supply of standard, reproducible rock chips that
can be clamped in a vise.

But I do have plenty of nails.

The blunter point of a nail head seemed like a much better imitation
of a sharp chip with a long edge than a wooden needle-point.

So it's not too bad that I used a nail head in the unrefuted test, is
it? I mean, except for that weird theory that rock chips can't cause
flats.

Incidentally, I tried Frank's suggestion ad hoc today.

Glancing at my front tire on a long straight stretch of road, I
noticed something too small to be identified whipping around. It
certainly wasn't a complete goathead, which is easily recognized.

Whatever it was, it ticked the finger of my glove a time or two and
then vanished. Obviously, it had to be stuck into the tire, and
equally obviously it was knocked out after hitting my glove a few
times. Whether it saved the tire is another matter.

Where, incidentally, were tire savers ever "proved demonstrably
ineffective," outside your somewhat contradictory memories of your
Wednesday tire patching circle?

Cheers,

Carl Fogel

 

[[email protected]]

[email protected] wrote:
> On 1 Nov 2006 18:59:23 -0800, [email protected] wrote:
>
> >
> >[email protected] wrote:
> >> What a weird thread... why am i responding to this?
> >>
> >> First off I fortunately do not live in an area with 'goathead'
> >> thorns. Though I am familiar with them from bicycle trips
> >> to NM, and those thorns are indeed wicked.
> >>
> >> I've been using these continental tires for the past two
> >> years that have some sort of aramid belt. I can say,
> >> based on my experience, that these new armored tires
> >> are much tougher then the older kevlar belted ones. I've
> >> had them stop several shards of glass, and one large
> >> thorn. The thron had broken off flush with the tire and I was
> >> able to pick it out of the (still inflated) tire. The tip had
> >> broken off at the aramid belt.
> >>
> >> So perhaps you will lose a few minutes to rolling resistance...
> >> who cares, sounds like you are wasting for more time
> >> than that fixing flats at this point.
> >>
> >> At worse you could use the more clunky tires during the few
> >> months out of the year when the thorns are a problem.
> >> Anyway you seem to be enjoying your thorn ordeal,
> >> in a perverse sort of way. And you're doing a favor to
> >> other cyclists mopping all those pesky thorns up.
> >>
> >> All I got to say on this.
> >>
> >> Eric
> >
> >{edit} wanted to add the tires I'm using are slicks,
> >not thick heavy treaded tires. Get some aramid belted
> >slicks for your road bike. Nothing to lose but a few $$$,
> >and perhaps much wasted time fixing flats.
>
> Dear Eric,
>
> Alas, my slick tires have Kevlar belts. The aramid fibers offer no
> real resistance to the thorns. As Jobst points out, you might as well
> expect steel wool to stop a darning needle. Kevlar belts are better at
> stopping glass and rock chips.
>
> Kevlar belts do reduce goathead flats to some degree, but the trick is
> just that they increase the thickness that the short but evil thorns
> must penetrate.
>

Right, have you tried any of the aramid tires? I think the
material is tougher than kevlar and may stop most
of the thorns. Those thorns are tough, but not as tough as
rolling over a nail or a staple. When the tip of the thorn hits
the aramid it likely will fracture and your tire will end up
with a harmless splinter. That's been my experience with
the aramid tires I've been using. I haven't gotten a flat
since I started using them, almost two years now. I've
often used kevlar tires in the past and they never seemed
to stop glass or thorns.

I think you are losing track of things worrying about five
minutes one way or another.

Eric