From: John De Armond
Subject: Blowout Damage
Date: Mon, 08 Nov 1999 17:14:58 EST
Had a blowout on the Itasca MH this weekend. It handled amazingly
well considering how tall it is. No idea why, as the tire came off
the rim and passed us up on its trek to find a final resting place
up in the woods on the side of the interstate.
I'm writing to call attention to something most people don't think
about - collateral damage. The steel belts whip around like scythes
and can reach out up to about 2 tire diameters. In my case, the
whipping belts completed stripped the shore power cord storage box
from the RV, knocked the black water tank valve off (OK, didn't
really want to find a dump station anyway :-), shattered some
fiberglass underskirting, stripped off other skirt supports, removed
the mud flap and punctured the light gauge sheet metal box that
serves as the base for the couch right above the wheel. It even
polished the rust off the exhaust pipe!. The potential for damage
was much greater. The built-in propane tank is only a couple of
feet forward and the copper line runs above the wheel. The plastic
sheathing was stripped off the line but the line itself is OK. This
I've only had this MH about a month and doing something to protect
the underside from tire damage was on the to-do list. I have had
blowouts on my step vans but they have strong inner fenders that
contained the damage and nothing was harmed other than my shorts!
My plan, which has now bubbled to the top of the priority heap :-),
is to install a strong inner fender similar to the ones on my Step
Van. I've talked to a friend who is a welder/sheet metal fabricator
and he says he can fabricate such a shield and attach it with
brackets to the frame with little trouble or expense.
This is something that everyone needs to think about and look at.
The replacement tire will cost about $100. I have perhaps a
thousand dollars' worth of collateral damage to deal with. And this
is minor as blowout damage goes.
From: John De Armond
Subject: Re: Blowout Damage
Date: Tue, 09 Nov 1999 13:30:07 EST
> Neon John wrote:
> > Had a blowout on the Itasca MH this weekend.
> > I'm writing to call attention to something most people don't think
> > about - collateral damage. The steel belts whip around like scythes
> Good post, John. You didn't say whether the MH was new or
> used. Can you tell us anything about the age and condition
> of the tire and/or rim?
MH is an 82. Previous owner said the tires were about 4 years old.
My tire dealer inspected them, replaced two and said the other two
were OK. One of the OK ones blew. Needless to say, the other "OK"
one is being replaced, as is the spare.
From: John De Armond
Subject: Re: Blowout Damage
Date: Wed, 10 Nov 1999 01:36:23 EST
seymour goodman wrote:
> Neon John wrote in message <38274BB0.firstname.lastname@example.org>...
> >Had a blowout on the Itasca MH this weekend <snip>
> Great post John! Glad to hear there were no injuries. I never thought
> about how much damage the steel belts in a tire could cause! There was a
> post here a few days ago about a fellow telling about a long trip with a new
> used MH- he mentioned that the tires were 13 years old (!) & that some
> people advised him to replace them- but since they looked so good he was not
> going to waste money replacing perfectly good tires! At the time I read
> this I thought this was stupid- now I know he was!
I read some of that thread before the name calling started...
Several people suggested having a tire dealer look at the tires,
followed by others asserting that all tire dealers are thieves. My
experience shows that none of that advice is any good. My tire
dealer is also a good friend. He looks out for my interests and has
for years. >He< could not tell by inspection that my tires were
bad. I didn't replace them all because I relied on the previous
owner's claiming them to only be 4 years old. I suspect this might
not be accurate. The only safe solution to unknown tires is to
simply replace them - after all, it's not that much money. I'm
certainly going to spend more than the $100 per tire on repairs from
the blowout and that's with me doing the work!
One thing I think trips up people when discussing tires is they
forget just how highly loaded MH tires are. On a car, the safety
margin is so high that one can get away with a LOT and not have a
tire fail or else have it fail gradually (tossing tread chunks,
etc). Situation is much different on the MH. My MH's tires are
right at their rated load capacity. Little margin for error.
> Thanks for the info & hopefully your tire troubles will be over!
Thanks. The trouble are solved. New skins on all 4 corners plus
Subject: A tire dealer's response to John's blow-out
Date: 12 Nov 1999
Howdy. I figured I'd share some knowledge(?) with you regarding tires.
I'm 42 and was born and raised in the tire business by my father. My
father, just having gone to the Lord last August, was a very honest and
caring person. Hopefully he has handed down some of his honesty and
care to me, thus I'll try to share a little tire info with you.
First, John, I'm very pleased to hear that your incident ended so well,
many do not.
Tires today are manufactured in a competitive market where every
manufacturer is bragging 50, 60, 70,...100 thousand mile warranties!
Now wait a minute, somethings screwy here from my point of view. Until
the last few years most tire-manufacturers had their pro-rated
warranties *and* a time limit on the warranty...normally four years. In
the last few years most of them have increased the time limit to around
Now, think about it...if you average 12,000 miles a year (seems like a
lot to me, but I'm the cat that just bought my first RV, a '74 Dodge
Class C with drooping rear end!) it would take you 5 years to wear out a
60k mile set of tires. If you only average around 6k miles a year it
would take you 10 years to wear the set of tires out and by that time
the "casing"(body) of the tire would be ancient. When the casing wears
out you are much more apt to start getting the tread seperations,
cracking beads, shoulder seps, and a few other maladies. You need to
remember that the casing is what holds most everything together...tread,
sidewall, bead, etc.,.
From my years in the business it seems that the best mileage tires are
the ones that wear out in about 4 years, whatever your driving mileage
might be. In other words, if you drive cross-country a lot and rack
up loads of miles...buy a high-mileage tire, on the other hand if
you don't put many miles on the RV buy a lower-mileage tire. That way
the casing is still "alive" but aging when the tread is finally gone
and you know (by eyeballing the tread) that it's time to replace the
tires. That way you get to start over with completely fresh tires
that are new and "alive". It's very deceiving to look at your tires and
see good-looking, deep tread on them, and yet the casing is old and
On every tire is a DOT(Dept. of Transportation) number. This number
designates the manufacturer, plant, etc., *AND* the date of
manufacturer. Almost without exception (probably some imports might be
different) the last 3 digits represent the date of manufacturer. The
first two of these three digits represent the week and the last digit
the year. The DOT number is stamped only on one side of the tire and is
normally on the "unstyled" or "black-wall" side of the tire so you might
have to crawl under the RV and look for the number from the inside. If
the tire is over four years old check it out good...from the beads to
the center of the tread.
What do you look for? (This applies to new tires, too.)Well, anything
that doesn't look "right". Excessive cracks appearing in the channels
between the ribs, non-uniformity of the tire in any area, cuts, nails,
etc.,. Also note that an "inny", a depression in the sidewall of a tire
is actually normal, but if you see an "outy" that bulges outward that
tire should be replaced asap.
One thing that you should really check out is the bead area of your
tires. A common weakness of heavier-ply RV-sized tires is the area just
above the actual bead. This area should be inspected for splits running
parallel with the bead. These splits can be from a fraction of an
inch long to completely going around the tire. The splits, in the
beginning, will almost look like razor-blade slices and over a period of
time they will gap open more and more, eventually causing a catastrophic
failure. CHECK THE BEAD AREA!
All tires will exhibit what is called "weather checking" or as folks
call it "dry-rotting". Dry-rotting is much more serious than
weather-checking, being as weather-checking is primarily superficial/
cosmetic and of no significance.
Dry-rotting normally happens when a tire is flat and sits in that state
for a time, normally causing the flexed area to crack badly.
Dry-rotting is also caused from not "oiling" your tire. A tire is a
petroleum product and if it sits static (not moving) for an extended
time it will begin to "dry out". To prevent this simply drive the
vehicle occasionally to keep the rubber "alive". RV's and boat-trailers
are something we seldom see with worn-out tires on them...they usually
are replaced because of dry-rotting caused by sitting up flat or either
from not being used or replaced simply because of age.
Running out of time here so let me hit a few more points.
Get an AIR GAUGE and USE IT! Radial tires have what is called sidewall
deflection...most folks refer to it as the "baggy look". It's really
hard to tell visually whether a radial is low in air or not. Buy a GOOD
air gauge. Get your tire dealer to air your tires up to operating
pressure and then check them with YOUR gauge, if there's any
discreptancy ask him/her to get a different gauge and stick the tires
with it to see if one or the other of the gauges is reading
incorrectly...a small difference is ok, it's not rocket science, ya
know. :) Tires that are run underinflated will wear faster and at times
fail because of overload (if they're under-inflated then they're
overloaded, aren't they?). Tires that are overinflated will also wear
faster and are more subject to impact damage because they don't have the
shock-absorption capabilities that they would have at correct air
Speaking of the "bag" aspect of radial tires... The sidewall of a
radial tire is it's weakest point...most of the time only being built
with a minimum of plies in it. Be careful making those turns and keep
from curbing your tires. Impacting the sidewalls can destroy the tire
and a lot of times it's a delayed destruction...waiting till the tire
gets heated up to highway speeds. Also, impact damage can be sustained
when you run over a blunt object (rock?) in the road...you hold your
breath and wait to see if anything blows but it doesn't...later on,
sometimes much later on you discover a knot on one of your tires. The
impact actually "bruised" your tire, letting air seep in between the
casing and the tread rubber.
If you're driving down the road and "something feels funny" stop and
check your tires. It could be a separated tire that's getting ready to
blow or it could be a flat tire. A flat tire on a dual is hard to
detect, but it will tend to give you a sense of swaying and instability.
A few problems with running a tire flat are basically that the tire is
non-repairable, it can self-destruct, and it can catch on fire. Ever
try to extinguish a burning tire?
Don't "plug" a tire. It should be patched from the inside. When a nail
or other object enters the tread of a tire it can actually rub against
the inside of the sidewall, wearing through cords of the casing. Though
you plug it and all appears well, the broken cords have weakened the
casing and tire-failure can result. If you have a tire than has been
run flat a short distance and appears to be repairable be sure to tell
the repairman what happened...the flexing of the sidewall of a flat tire
can weaken the cords in the sidewall (kinda like taking a wire and
bending it back and forth till it gets hot and breaks), this creates the
atmosphere for a "zipper" explosion where the tire's sidewall suddenly
rips open parallel with the bead...every few months a tire technician
dies due to a sudden zipper explosion. They're DEADLY!
Along with "don't plug a tire", don't use "fix-a-flat". Tire repairmen
despise it because it makes it almost impossible to glue a patch to the
tire after it's had fix-a-flat in it. Also, if you use it be sure to
tell the tire repairman...some of the propellant is flamable/explosive.
Of course if I was in the middle of the desert, miles from anywhere and
no help in sight, I'd use fix-a-flat, have a 12-volt air-compressor and
have a plug-kit handy, too. We gotta look at our options, ya know. :)
Well, that's about it...times fleeting. Remember, check your air
pressure and visually inspect the rubber. It's the only thing between
the asphalt and you. Respect air-pressure...it can be DEADLY!!!
Hopefully I didn't ramble too much. Hope some of this helped.
Take care and God bless u es urs,
L.A. (Lower Alabama)
From: John De Armond
Subject: Re: A tire dealer's response to John's blow-out
Date: Fri, 12 Nov 1999 01:02:40 EST
> Howdy. I figured I'd share some knowledge(?) with you regarding tires.
> I'm 42 and was born and raised in the tire business by my father. My
> father, just having gone to the Lord last August, was a very honest and
> caring person. Hopefully he has handed down some of his honesty and
> care to me, thus I'll try to share a little tire info with you.
> First, John, I'm very pleased to hear that your incident ended so well,
> many do not.
Thanks. This was the most "interesting" blowout I've ever had
because of the height of the MH but everything worked out.
Thanks for taking the time to write that post. Very informative.
Now to specifics.
> On every tire is a DOT(Dept. of Transportation) number. This number
> designates the manufacturer, plant, etc., *AND* the date of
> manufacturer. Almost without exception (probably some imports might be
> different) the last 3 digits represent the date of manufacturer. The
> first two of these three digits represent the week and the last digit
> the year. The DOT number is stamped only on one side of the tire and is
> normally on the "unstyled" or "black-wall" side of the tire so you might
> have to crawl under the RV and look for the number from the inside. If
> the tire is over four years old check it out good...from the beads to
> the center of the tread.
I just spent the last 20 minutes under my MH looking at the "good"
tire that didn't blow out. Finally found the DOT number (on the
inside, natch!). Help me figure out what I'm looking at. This is a
Dunlop 8.75R16.5LT US manufactured radial tire. The coding after
the "DOT" is DAXK 816 500. The last three digits look like they
were molded by a "quickchange" die of the type that would be changed
on each shift. If that is the date code, then this tire made in the
50th week of 1990 is a leeeetle bit older than the 4 years the
previous owner said it was. Am I interpreting this correctly?
> Don't "plug" a tire. It should be patched from the inside. When a nail
> or other object enters the tread of a tire it can actually rub against
> the inside of the sidewall, wearing through cords of the casing. Though
> you plug it and all appears well, the broken cords have weakened the
> casing and tire-failure can result.
I'd modify that a bit. I'd say "don't plug a tire as a permanent
remedy". I carry a plug kit and a "D" size cylinder of CO2 in my
vehicles and I can't count the times that I've pulled a nail,
plugged the tire, inflated it and was able to drive it to the tire
store for permanent repairs without having to suffer through the
hassles of getting the spare out.
While on the subject, my inflation source is a "D" size medical
oxygen cylinder re-valved with a CGA-320 CO2 valve. This is the
cylinder many oxygen-dependent people carry around in the shoulder
bag. It is half the size of the "E" tank that people commonly walk
around with on a cart. This tank will hold about 5 lbs of liquid
CO2. I fill my own tanks from my restaurant's bulk tank but I could
also get it refilled by most any beer distributor. The rest of the
system consists of a CGA-320 nipple, a Tee, a bicycle pump hose and
chuck (open flow) and a 75 psi relief valve. This system relieves
the need for a regulator while protecting from the approx 900 psi
pressure in the cylinder.
This setup will fill several car tires or a couple of truck tires.
It has saved my cookies several times. I picked up my cylinders at
a flea market for a couple of bux each.
>If you have a tire than has been
> run flat a short distance and appears to be repairable be sure to tell
> the repairman what happened...the flexing of the sidewall of a flat tire
> can weaken the cords in the sidewall (kinda like taking a wire and
> bending it back and forth till it gets hot and breaks), this creates the
> atmosphere for a "zipper" explosion where the tire's sidewall suddenly
> rips open parallel with the bead...every few months a tire technician
> dies due to a sudden zipper explosion. They're DEADLY!
I've never seen a radial tire that has run flat even a few feet that
I'd feel comfortable repairing. I consider a tire that ran flat to
be trashed. To tell the truth, I've never been able to get off the
road and get stopped fast enough to keep the tire from disassembling
> Well, that's about it...times fleeting. Remember, check your air
> pressure and visually inspect the rubber. It's the only thing between
> the asphalt and you. Respect air-pressure...it can be DEADLY!!!
> Hopefully I didn't ramble too much. Hope some of this helped.
Thanks for writing, Ed. As much trash as has been spewed at tire
dealers in the last couple of weeks in this group, I'd not blame you
for not saying a thing. Glad to see there are other dealers out
there as competent as mine. One nitty picky little thing, "Tire
Technician"? What, they changing transistors in the tires or
something? This is like the guy who pumps my grease trap whose
business card carries the title "waste management technician".
Sheesh! Semi- :-)
From: John De Armond
Subject: Re: A tire dealer's response to John's blow-out
Date: Sat, 13 Nov 1999 02:52:01 EST
> In article <382BADE3.243544BB@bellsouth.net>,
> Neon John <johngdNOSPAM@bellsouth.net> wrote:
> (Ed pruned out a bit of text here...)
> > > On every tire is a DOT(Dept. of Transportation) number. This number
> > > designates the manufacturer, plant, etc., *AND* the date of
> > > manufacturer. Almost without exception (probably some imports might
> > I just spent the last 20 minutes under my MH looking at the "good"
> > tire that didn't blow out. Finally found the DOT number (on the
> > inside, natch!). Help me figure out what I'm looking at. This is a
> > Dunlop 8.75R16.5LT US manufactured radial tire. The coding after
> > the "DOT" is DAXK 816 500. The last three digits look like they
> > were molded by a "quickchange" die of the type that would be changed
> > on each shift. If that is the date code, then this tire made in the
> > 50th week of 1990 is a leeeetle bit older than the 4 years the
> > previous owner said it was. Am I interpreting this correctly?
> Manufactured the 50th week of 1990...or either 1980<g>. The last three
> digits are molded by a changeable plate...this allows them to change
> them out each week and helps keep track of production runs.
Pretty sure it's 1990. The MH is an 82 model and I got the original
bias ply tires and wheels in the deal. They look REALLY rough from
dry rot even though the tread's all there.
> You interpreted the DOT correctly, I was kidding about the 1980 thing.
> Well, I'd at least say the previous owner was incorrect in what he
> stated. The tires might have actually been purchased in '95, though
> manufactured in '90. This would make the tires old before they ever hit
> the asphalt. What this says to me is that someone either had some very
> poor inventory turns, or that these tires got stuck back somewhere, were
> discovered and sold (should have been sold at a deep discount just to
> get rid of dead-merchandise and with the customer understanding what
> he's getting). Of course, the previous owner might have been victim of
> "how time flies when we're having fun". But, by the DOT number above
> they were definitely manufactured in late 1990.
This guy had been a used car dealer so I suspect he didn't make a
"mistake"! I've found some other minor inconsistencies in his
story. All works out, I think. After I got through with all the
other negotiating, I got him to knock off the price of a new
generator cuz the old one wouldn't turn over. Turned out to be a
brush stuck in its holder :-)
> 900PSI!!??? Man, what kind of pressure do those tanks normally have
> when used for their intended purpose? I have no idea about the
> structure of these tanks, but just the idea of holding one of those
> tanks with that kind of pressure inside gives me the willies. You've
> got me very interested in the rated pressure of these tanks and
The standard service pressure of these little tanks is 2250 psi. I
forget what the hydro test pressure is but it is in excess of 3500
psi. Doesn't that give you the warm cuddles when you see someone
tossing those little oxygen cylinders around like they were salamis?
CO2 is stored as a liquid so the pressure varies with the
temperature. At freezing it will drop to about 400 psi. CO2 tanks
have a service pressure rating of 1800 psi. If that gets your
attention, consider that the auto industry is giving serious
consideration to using CO2 as the air conditioning refrigerant!
This is just in case the greenhouse gas hysteria gets out of hand.
R-134a is allegedly a greenhouse gas, if you pay any attention to
> A friend of mine had just finished fixing a tire off of a set
> of hand-trucks...a 4.10-4 that probably had 12-14psi...and was holding
> it in his hand. For some reason it blew. He was lucky, only had to
> wear the cast on his hand for about six weeks. Don't ever get too
> comfortable with air pressure. But, provided the system is solid, it
> sounds like you've built a nice air-tank setup.
yeah, this is a pretty nice setup. I've been doing some variant of
this for years. I'd previously used a 3 lb CO2 cylinder used for
pumping a beer keg. About the size of a 3 cell flashlight. One of
these would fill a couple of car tires. I didn't like the hassles
of having to refill the thing after each use, particularly before I
opened the restaurant, so I jumped on these oxygen cylinders when I
found 'em. If the pressure makes you nervous, a fairly inexpensive
beverage regulator is available. I don't like dealing with the bulk
of the regulator so I use care and the relief valve to take care of
things. The bicycle-type open flow chuck won't trap pressure in the
hose. I've never actually caused the safety to lift other than to
test it. The worst part of this setup is that CO2 is an excellent
refrigerant. Everything including the hose ices up before the tire
filling is finished. That has to be kept in mind as the tire is
filled. The CO2 goes in very cold and expands a lot as it warms
up. A tire can be overpressured if it is filled to its rated
pressure with cold gas.
> Regarding competent tire dealers my experience has been that
> mom-n-pop/family-owned dealers are better to deal with. They tend to
> have solid, regular employees who know what they're doing and have
> probably been doing it for quiet a few years. Most of
> these types of dealers are after the repeat business rather
> than the "one-shot" business. Chain-stores, discount stores, etc., have
> more of a transient employee roster...here today gone tomorrow...the guy
> you bought your tires from today might not be there to handle a problem
> for you tomorrow. Your mileage may vary. :)
I was going to say that when my typing pinkies wore out :-) My
dealer friend has been there for 30 years or so. He closes for a
week at Christmas and the 4th and pays each employee a $2k bonus at
the beginning of each holiday. That's mighty fine incentive for his
employees to stick around :-) Funny thing is, his prices are
usually equal to or only a couple of bux a tire higher than the
> "Tire technician"...chuckle. Kinda like "Sanitation Engineer"?
> Actually the professional tire-changers that I know refer to themselves
> as...tire changers. I'd be kinda leary of a tire technician working on
> my tires...he might get his hands dirty or break a nail.<grin>