Date: Sun, 31 Mar 2002 17:47:14 +0000
Reply-To: Mike Finkbiner <mike_l_f@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Mike Finkbiner <mike_l_f@HOTMAIL.COM>
Subject: Re: Hoop Humbug----
Content-Type: text/plain; format=flowed
"Terry K." <CTONLINE@WEBTV.NET> said -
Phil,
The point I was trying to make was---
The Cooper's aren't suppose to be worth a tinker's damn because of the 2
ply sidewall--and them darn HD van tire's are of the same
construction!!!!
How can they be any worse / better than the Van tire that is constructed
the same way?
>>>>>>>>>>>>>>>>>>
Terry -
The number of plies isn't a measure of how tough, or how stiff, or how
strong the tire is.
Back in the old days, before Michelin developed the radial tire, tires were
rated as four-ply, six-ply etc. based on the number of layers of fabric in
the rubber, laid diagonally across each other (Bias-ply). Radial tires have
a belt of steel/fabric, whatever, under the tread, and one or more plies of
fabric where the fibers run Radially, (like the radius of a circle) out from
the center, making the sidewall, under the belt and tread then back to the
center on the other side.
At any rate, the important thing to look at is what the load range is and
how much pressure the tires can handle.
VW recommends 39-48 psi, depending on the size and position of the tire.
Most passenger tires won't handle 48 psi. In the US, most of the choices
that will are light truck tires. Some foreign tire companies make what they
call a Commercial tire, which is about the same thing.
Then there are Reinforced tires - which I take to mean able to handle more
pressure than common passenger tires.
Different tire manufacturers will take different paths to reach that goal.
All of the ones that I have seen use two-ply sidewalls and four-ply treads,
but presumably made of stronger material than they use in their 35-psi
passenger tires. I imagine other companies have more plies in the sidewall,
and it probably could be done with one-ply of the right material.
We want a stiff tire to avoid sway. That means higher pressures than most
passenger tires can handle.
Another thing to consider is that the maximum load rating of a tire is at
the maximum spec pressure. If you run at lower pressures, you can't carry
that heavy a load.
IMHO, that's why my '87 Westy door sticker says 48 psi for the 185R/14 C
(Commercial) - no load range specified, and 40 psi for the 205R/14, LR 97.
The 185 Commercial will handle about 1400 Lbs at 48 PSI. The 205 LR 97 will
handle about 1600 lbs AT 50 PSI, and at 40 psi will still handle 1400 lbs
easily. I suspect the 205 at 50 psi would be too stiff for a comfortable
ride.
Check your door sticker for your vehicle.
There are exceptions and ammendments to all of this, and there are more tire
designs out there than existed in the '80's, but going outside the envelope
of the Vanagon design is an experiment. Some will work, some won't, and not
working can have serious consequences.
Off-road tires will have different requirements, but the load range/pressure
specs should be considered if they are driven on the highway.
People do get tired of the tire thread, but it is confusing, and most tire
shops have no idea of the correct sort of tire and pressure for the Vanagon.
Good luck!
- Mike Finkbiner
'87 Westy
Moscow, ID
mike_l_f@hotmail.com
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