This evening I read on Epinions.com about similar problems with Marathon tires on a new Fleetwood 5th wheel. While researching tires, I ran across this and I thought it might be benificial to members here. Makes me want to check the date codes on my tires!
Thought this might help some of you. Copyied from rv
The useful life of a tire is only five to seven years.
For cars and trucks driven every day, the tread
usually wears out in less than five years. For RVs
that sit for a good part of the year, five years can
pass with a lot of tread still left on the tire.
Although you may not want to replace what looks like a
perfectly good tire, riding on tires more than five
years old greatly increases the risk of a blowout.
Date Codes: Every tire has a date code stamped on the
sidewall, which gives the date that the tire was
manufactured. They look something like this: DOT PDHH
MLOR 3403. The date code can be on either side of the
tire, so you may have to crawl underneath the rig and
look on the inward facing side. The date code always
starts with the letters DOT and ends with a 3 or 4
digit number. That last number is the date code, which
tells you when the tire was manufactured. The first
two numbers indicate the week (out of 52) and the last
one or two digits indicate the year. For instance,
3403 means the 34th week of 2003, or the last week in
August 2003. Starting with the year 2000, the date
codes have two digits for the year, prior to that,
only one. A date code of 079 would indicate the
seventh week of 1999, or the third week of February
Tires deteriorate with age, even when sitting on a
shelf, so always ask to see the date code when you
purchase new tires and insist on tires manufactured
within the last few months. The tire dealer may give
you a funny look because most consumers don't know
about date codes.
Tire Size Designations: That jumble of letters and
numbers on the sidewall of the tire is the tire size
designation. The first letters indicate the type of
tire: P for passenger car, LT for light truck, and ST
for special trailer. Bus and medium-duty truck tires
have no such designation. The next number is the width
of the tire, given in millimeters, followed by a
slash. The number following the slash is the ratio of
width to section height (only important to tire
engineers) followed by a letter: R for radial ply or D
for diagonal or bias ply. It ends with a number which
gives the inside diameter of the tire in inches. A
tire with the designation ST225/75R15 is a special
trailer tire that is 225 millimeters wide with a width
to section height ratio of 75. It is a radial ply tire
that will be mounted on a 15-inch wheel.
Load Range: The load range of a tire is indicated by a
letter, A through E, and is stamped on the sidewall of
the tire. Tire charts, available from any tire dealer,
have these letters in parentheses after some of the
tire load limits. The letters are placed next to the
maximum weight for that load range.
Which Type of Tire to Use
Tires are engineered specifically for different types
of vehicles. Passenger car tires are designed to
provide a soft ride and grip the road during turns and
adverse weather. Light truck tires have stiffer
sidewalls in order to carry heavier loads, but also
are engineered for safe handling and road gripping
ability. Trailer tires, on the other hand, are
designed to give a soft ride and to slide sideways or
scrub the road while cornering. Because of these
differences, never put light truck tires on a trailer.
Some people think that if the tire is good enough for
a truck it must be good enough for a trailer, but this
is a fallacy. Light truck tires are not engineered for
the unique stresses of trailering.