In a message dated 3/5/02 10:32:20 PM, mike_l_f@HOTMAIL.COM writes:

<< Chris -

Tires used to have 4,6 or 8-ply sidewalls, as well as tread (bias-ply tires,
many moons ago).  I believe (but have not been able to find any confirmation
for this) that 'Reinforced' tires are those which can carry a higher
pressure, and so are stiffer.  Most P rated tires say 35 psi maximum.
Heavier duty tires say 44, 50 or more.

Running a 50 psi 205/70R-14 Load Range 97 tire at the recommended 40 psi on
the rear of my '87 Westy means it can support less than the maximum weight
rating, but it is still stiffer than a 35 Psi P rated passenger tire would
be.

Have you ever seen an official definition of reinforced? >>

Yes reinforced tires carry a higher load rating, but not all higher load
rated tires are reinforced.  Generally speaking, the higher pressure tires
are stiffer, and give a firm ride.

You need reinforced sidewalls to limit tire roll and sway.  The stiffer side
walls help you keep better control over your van while turning and cornering
as well as in windy conditions.  They limit the amount of lean the tires have
and prevent tire blowouts.  Reinforced tires are needed on tall heavy
vehicles like our vans.  They should also be required on SUVs, but that's
another story. (remember the 35psi Firestone tires on the Explorer?)

When you take a curve, weight is shifted to the inside tires and a lot of
stress is put on the tire sidewalls.

Ply ratings anymore are just that, a rating.  They don't actually stand for
the number of plies.  You can have 4 ply tires that carry a 6 or 8 ply
rating.  In the old days tires were rated by the number of plies they had.
Today you can get the same strength with less, but the rating is still used.

Steve Lashley
SKL Enterprises Inc.
http://EuroCampers.com
636-797-9015
636-789-2127 fax