Newsgroups: rec.bicycles.tech
From: jbrandt@hpl.hp.com (Jobst Brandt)
Subject: Re: Should I Rotate My Tires?
Date: Fri, 5 Jan 1996 21:26:12 GMT

John Andersen writes:

> My experience is that most flats occur on the back, maybe it has
> something to do with the weight of my back side.  This being the
> case, I keep as much rubber under that end of the bike as possible.

Most sharp obstacles lie flat on the road and must be upset by the
passing of the front tire or another vehicle to assume a threatening
position.  I believe this is the principle reason for more flats in
the rear than the front, both on bicycles and motor vehicles.

On the other hand, puncture vine thorns always have one of their
spines in the vertical position, being tetrahedral shaped, so you are
probably more likely to get thorn flats in the front tire.  Snake
bites (pinch flats) prefer the loaded wheel, but often not.

> Go ahead and rotate. (Reciprocate ??).

Because front tires usually outlast back tires at least 2:1, the often
die from old age if you don't rotate them.  The casing gets grey and
fuzzy if its a skin wall and suffers through much water.

Jobst Brandt      <jbrandt@hpl.hp.com> 

Newsgroups: rec.bicycles.tech
From: jbrandt@hpl.hp.com (Jobst Brandt)
Subject: Re: brushing off fendered tires?
Date: Wed, 10 Jan 1996 02:23:37 GMT

Tom Ruta writes:

>> After some practise on empty roads, I learned to clean off my tires
>> with the top of my shoe -- without sticking my foot in the wheel or
>> getting tangled up in the chain.  This results in dirty shoe tops,
>> but many less flats (I suspect).  My bike has fenders also.

> True but unfortunate story...  [grotesque disaster described]

> Bottom line: use one of those wheels cleaners (little bracket) ;
> Kevlar tires; or really, really practice and pay attention when you
> use a hand or foot to clean a wheel.  Or you can always stop the
> bike.

Wiping tires is an old trick that riders did when they had nothing
better to do while cruising along.  If you observe the ritual, it
should be apparent that it serves no practical purpose because between
the time the hazard is run over and the wheel wipe, two or more wheel
revolutions take place.  Anything that's going into the tire is in by
that time although the tube may not be punctured yet.

Beyond that, my tire wiping friends had no less flats than the average
but that proves nothing because I also have friends who never find
tools or money on the road, and they get lots of flats... but that's
because the are not especially observant.  Any sharp object that
enters the tire is usually in on the first contact and is definitely
in with its protruding end trimmed by the third.  Puncture vine is the
most insidious offender and it takes only the first contact to penetrate.

Tire savers, the little gizmos that drag on the tire just ahead of the
brake bridge on the rear tire, serve to fill your shoes and socks with
road dirt every time the road is even slightly moist.  I think you'll
not find them generally available in bicycle shops for that reason.
Besides, I am convinced they are useless.  I think they had their
heyday in the 1940's or there abouts.

Look where you're going and avoid flats.  All the mystery cures don't
add up to a statistical hill of beans.

Jobst Brandt      <jbrandt@hpl.hp.com> 

From: jbrandt@hpl.hp.com (Jobst Brandt)
Newsgroups: rec.bicycles.tech
Subject: Re: Are Axial Pro's More Flat prone in the rain than other tires?
Date: 29 Jul 2000 01:09:29 GMT

Steve Palincsar writes:

>> The rain seems to act as cutting compound and increases risk of
>> puncture from glass and sharp rocks.. I experienced the same
>> problem with Avial pro as well as with Vittoria Open Corsa CXTT

> That's been true for me for every brand and type of tire I've ever
> ridden in the past 30 years.  And, to add insult to injury, it's
> impossible to patch a tube in the rain.  Well, almost impossible.
> And that includes all kinds of non-"high performance" clinchers,
> road tread 26 x 1.5" commuting tires, 28 x 1 1/2" roadster 3 speed
> tires, 27 x 1 1/4, 27 x 1 1/8, and 700 x 23.  Equal oppourtunity
> misery.

Tire size has little to do with punctures but water on the road does.

> Could be something to do with the water helping the glass to stick
> to the rubber, or it could be as simple as you can't see the glass
> because of the water on the road, so you can't avoid it.

From the FAQ:
---------------------------------------------------------------------

Subject: 8.16  More Flats on Rear Tires
From: Jobst Brandt <jbrandt@hpl.hp.com>
Date:    Mon, 12 Aug 1996 10:45:42 PDT

Many sharp objects, especially those that lie flat on the road like
nails and pieces of metal, more often enter rear tires than the front
tires.  That is because the front tire upends them just in time for
the rear tire to be impaled on them.

For example, nails seldom enter front tires.  When dropped from a
moving vehicle, nails slide down the road, and align themselves
pointing toward traffic, because they prefer to slide head first as
they would when laid on a slope.  The front tire rolling over such a
lengthwise nail, can tilt it up just in time for the rear tire to
encounter it on end.  I once got a flat from a one inch diameter steel
washer that the front tire had flipped up so that the rear tire struck
it on edge.  When following another wheel closely, the front tire can
get the "rear tire" treatment from the preceding wheel.

The front wheel set-up effect is especially true for "Michelin" wires,
the fine strands of stainless wire that make up steel belts of auto
tires.  These wires, left on the road when such tires exposes their
belt, cause hard to find slow leaks almost exclusively in rear tires.

When wet, glass can stick to the tire even in the flat orientation and
thereby get a second chance when it comes around again.  To make
things worse, glass cuts far more easily when wet as those who have
cut rubber tubing in chemistry class may remember.  A wet razor blade
cuts latex rubber tubing in a single slice while a dry blade only
makes a nick.

As for pinch flats, aka snake bites, they occur on the rear wheel more
readily because it carries more load and is uncushioned when the rider
is seated.  The rider's arms, even when leaning heavily on the front
wheel, cushion impact when striking a blunt obstacle.

------------------------------

From: jobst.brandt@stanfordalumni.org
Subject: Re: Fixing a tire
Newsgroups: rec.bicycles.tech
Message-ID: <qcZ_a.11907$dk4.443932@typhoon.sonic.net>
Date: Fri, 15 Aug 2003 04:20:38 GMT

Brad <brad@ieee.org> writes:

>>> One more reason to stick with cheap tires....

>> That is the negative approach.  Most of us do well with high
>> quality lightweight tires.  How about watching the road more
>> carefully while riding.  Consider that most bicyclists don't have
>> your problem and for those that do, it's a rare occurrence.

> Haha, there is so much crap on the roads around here that you are
> bound to hit something now and again.  This is especially true when
> riding in a pace line where you can't see the road ahead.  Most
> bicyclists I know locally don't train on expensive tires because you
> will eventually hit a patch of glass or road debris.

That's the excuse most people who get many flats give, "our roads are
so full of ..."  Meanwhile, with what sort of jerks do you ride that
lead a pace line into hazardous debris?  In my club, guys who do that
are asked not to ride with us.

Learn how to avoid glass and thorns and get some good tires.

Jobst Brandt
jobst.brandt@stanfordalumni.org
Palo Alto CA