Broken Cord on Michelin Tire

[Henry Jay Hannigan]

NEIL:
Aint it safest just to fill air to whatever MAX it says on the
tire????? Anyway...that's what I've done on my BIRD and my car for
umpteen years.......
Regards,
Hank
90SP36

PS I have 12R22.5 Bridgestones on the BIRD and Goodyears on the
Honda toad.










--- In WanderlodgeForum@yahoogroups.com, "Neil & Pat"
wrote:
>
> Hi Pete, David, Greg, Randy and all else who have been following
this
> thread. You called for a tire engineer to make input into this
subject;
> well I have been doing that for 36 years now and also happen to own
and
> operate a Wanderlodge (PT-36 ) for the past 12 years and have
written
> extensively on the subject of RV safety in my book on the subject
as well as
> respond to many of the tire questions posed on this and other
forums.
> Perhaps I can help.
>
> The original question was re: a broken belt (actually shifted) on a
Michelin
> tire with the thought was this a problem on the Michelin tires and
would it
> be subject to warranty. At 27k miles the tire problem in question
is
> almost certainly the result of a "road hazard" either a rock,
shoulder drop
> off, hitting a curb or possibly even improper usage of "chocks" for
leveling
> or other purposes. Had it been a manufacturing problem it would
have shown
> up much before that time. You did receive proper advice in that
this is not
> a warrantable condition by the manufacturer but often dealers do
provide
> "road hazard" protection as a service to their customers.
>
> This is one of the major differences between truck tires and those
used on
> automobiles; in order to carry heavy loads much higher pressures
are used
> and the tire is normally operated at a lower deflection rating. On
trucks
> the deflection of the sidewall when normally inflated is on average
8% by
> design when it is properly inflated for the load carried, in
contrast on an
> automobile tire the deflection is approximately 12%, thus, yielding
a
> smoother ride and a tire less susceptible to impact loads as
mentioned
> above. For your interest aviation tires actually operate at 32%
deflection
> to carry the immense loads involved but do so with a duty cycle
limited to a
> few seconds. The "hoop strength" of the belt package" is under
immense
> tension from the inflation of the tire becoming more and more rigid
and
> unyielding as pressure goes up making the tire much more critical
to this
> type of abuse. So for our RVs we have a quandary, RVs are the only
vehicles
> on the road, which operate at 100% of the capability 100% of the
time making
> their safe operation somewhat precarious. We must carry the
correct (high)
> amount of air pressure to carry the load (at the correct deflection
rate)
> but should not exceed that pressure or operate below the required
amount.
> Higher pressure than required will yield decreased steering power,
braking
> power, higher impact type damage as well as decrease life; too low a
> pressure will result in over deflection, hotter running temperatures
> (possibly destructive), poor handling, greatly reduced life and the
> potential for catastrophic premature failure. Take your pick, but
none of
> these options are very appealing to me.
>
> The above realities of life is the reason why the tire
manufacturers, the
> RVSEF and myself all repeatedly attend and lecture at rallies and
anywhere
> RVers gather to spread the word that RVs are different and incur
> considerably more operator responsibilities from the
owner/operators. It is
> absolutely essential that you have your RV weighed properly wheel
by wheel
> to assure that none are overloaded and then and only then determine
the
> correct pressure for your specific RV under the conditions you
operate it.
> Plain and simple there is no other way.
>
> Always happy to be of assistance:
>
> Neil LeKander
> Author, The Rver's Ultimate Survial Guide
> http://www.rvsafetyinfo.com
>
> less likely to crush to the wheel rim, possibly protecting the tire
> from pinching damage, but the high pressure would also place the
tire
> under tension pressure ... so???
>
> Any tire engineers out there?
>
> Pete Masterson
>