Broken Cord on Michelin Tire

[Neil & Pat]

Hank, there is no question that under inflation is
significantly more harmful (and dangerous) that over inflation. However, as I listed in my earlier
response there are numerous problems with over inflation including some which
potentially dangerous or expensive or adversely affect ride comfort. Note the maximum pressure on the sidewall
is the correct pressure only when the tire is loaded to the maximum load also
shown on the sidewall. In your
case you obviously have gotten by with operating at the maximum and have
accepted whatever negative that procedure brings. I sincerely hope that your good luck continues into the
future.

Regards,

Neil

Author, The Rver’s Ultimate Survival
Guide

http://www.rvsafetyinfo.com

-----Original Message-----

From: WanderlodgeForum@yahoogroups.com
[mailto:WanderlodgeForum@yahoogroups.com]On
Behalf Of Henry Jay Hannigan

Sent: Tuesday, September 09, 2008
9:55 AM

To:
WanderlodgeForum@yahoogroups.com

Subject: [WanderlodgeForum] Re:
Broken Cord on Michelin Tire

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%40yahoogroups.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

>