Date:         Tue, 20 Apr 1999 13:48:02 -0400
Reply-To:     Paul Schiemer <schiemer@MAGICNET.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Paul Schiemer <schiemer@MAGICNET.NET>
Subject:      Tires, et al (LONG)
Content-type: text/plain; charset="US-ASCII"

One call nearly does it all anymore (as Goodyear has bought Sumotomo &
Dunlop recently).
My EMail was responded to immediately; replete with the name and number of
the Director of Information Worldwide (who wants to go nameless, if that's
okay with y'all).  Called him at home, and he was happy to answer my
questions- knowing full well I was going to paraphrase herein.

Here's the vantage point of one manufacturer:

The Vanagon (specifically the Westy which I was asking after) has a certain
displacement of weight supported by the suspension, tires and wheels.  A
fully loaded Westy, traveling at highway speeds, develops a lot of heat in
the tire (friction at work).
Their main concern with tire safety is preventing catastrophic failures of
the tire (as well tractability, wear, water rejection, etc.)  Most of all
they don't want a tire to blow out a sidewall at speed.  Forget, for the
time being, about commercial concerns (price, availability, and competition
in the marketplace).

If you're going to run your Vanagon 'round town in short bursts on the road,
with medium to light loads- a passenger tire will not develop the heat, and
won't destruct itself.
If you're taking a trip in your Camper; with family, friends, pets, and all
the junk you lug along- with any stint on the highway (at speeds of 50 mph
or better) you NEED a tire with a reinforced sidewall.  It can be a mere
twenty miles down the road (loaded like this) and you may be taking a
chance.
Most passenger tires DON'T have reinforced sidewalls.  In the old days they
used a 'bias ply rating' on tires that, ostensibly, referred to the number
of plys in the side wall (wraps as it is called in the business).  The
higher the wrap the stiffer the sidewall, the more loading it can take.
[When we use the word "loading" we're talking about deformations in the
shape of the tire under lateral acceleration (turns).  A stiffer tire is not
only stronger but it is more resistant to rolling onto the shoulder of the
tire (where the writing is).  No tire is designed to ride on the written
part.]

You get them hot, push down hard on them so the sidewall is deforming
somewhat (adding additional stress to the material), and then take a turn
(rolling resistance pressure onto the shoulder somewhat) you might be
flirting with disaster.
Although a catastrophic failure of the sidewall can occur while driving
along straight, not just during turns.

Now get this;  One of my buddies sends me an EMail stating their team
vehicle is a VW Vanagon GL, with roof rack and all the seats.  They run it
around venues with team members, parts, tools, and the roof rack full of
tires- sometimes driving between venues following the transporter- weighing
in at around 825 kg per tire (ie; max loading) on Michelin MX tires (with a
per tire rating of 1,540 lbs @ 40 psi).  They are over and above the rating,
obviously, and have yet to have any failures of the tires- in three years of
driving throughout Europe and elsewhere.  [Not to say they haven't had
flats, just no catastrophic failures.]
BUT, the MX is not considered a passenger tire, it has reinforced sidewalls,
and runs about $65.00 USD through mail order (I called around already).

I called the National distributor of one of the Oriental tire manufacturers
who put me on to their truck division head.  I explained what I was
researching, and he offered the following info:

They recommend an all weather tire with a higher ply rating for pretty much
the same reasons as stated above.  They have tires that fit the requirement
in both C & D ratings ("C" is a 6 ply rated at 1,600 lbs @ 50 psi, "D" is a
10 ply rated at 1,855 @ 65 psi).
I said, gee, those seem like awfully high pressures... to which he responded
it is all relative to the strength of the sidewall and the loading
characteristics of the vehicle.
We then branched into this part about 'ride comfort';  I want quiet, smooth,
safe, and comfortable tires on my Westy.  He says, while the harder tire may
ride a little bit 'stiffer' than a passenger tire, it won't make for an
'uncomfortable' ride, overall.  It will (probably) track as smoothly as a
passenger tire (in the fully loaded vehicle), and may make less 'noise'
even.
Ultimately they spend hundreds of thousands of dollars in research,
developing tires designed to accomplish a specific task.  Asking a tire
designed to handle one task to accomplish another is not recommended.  In
the event something DOES happen (and your using the wrong tire), you won't
have a leg to stand on coming after the supposed 'deep pockets' of the
manufacturer- you were outside the envelope of performance stated for the
tire.  CAVEAT EMPTOR (I guess he's been to that class on legal issues?)

I called around on those tires and they are selling for $79.00 & $81.00
respectively.

As a matter of fact I called two of the biggest mail order tire businesses
in the Country asking about their recommendations; getting about the same
result as described above.
An interesting note;  one guy says, why would I recommend a $45.00 tire when
I could recommend a $100.00 tire- the more I sell the more I get in
commissions.  If the $45.00 fits the bill, I'll tell them that.  If they
want to buy the MXT version of a tire that would work just fine in the MX
version on a specific vehicle, I'll go ahead and take their money.  It
doesn't do me any good to sell them a cheap tire, but if the cheap one
works, why sell them more tire than they need??  It's like shinning the
bottom of your shoes.
If the buyer tells me exactly what they are using the tire for I can give
them a list of possible alternatives from six different, major tire
manufacturers.  All of them about the same price, give or take, because they
study each others' pricing guides, and giving about the same performance
characteristics.  In the commonly requested sizes and uses, it's just that
close in competition.
We spend thousands of dollars on teaching our reps about tire technology and
product awareness, we'd fire anyone that just quotes what is easiest to
sell.

My bottom line on the thing is I'm switching from the Dunlop Axioms to their
C rated tire called SP/LT5, about $75.00 each- rated for 1,600 per tire (C)
at 50 lbs.  They get like 60,000 miles in the mileage warranty, so it's not
like I'm going to replace them that soon.  An ounce of prevention is worth a
pound of cure.
We're talking a difference of about $30.00 per tire, they are the correct
rating, and I'll have no worries about failures (at least up front in my
conscious mind).

And I swear you'll NEVER see me bring up this subject again!!  Thanks to all
of you who contributed to this thread, and hopefully we've all come away
with a degree of knowledge on the matter.  If anybody wants to chat abou
this- do it in a private EMail to me.    FIN.