Home » Public Forums » GMCnet » [GMCnet] Interesting information about tire load range!
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| Re: [GMCnet] Interesting information about tire load range! [message #110034 is a reply to message #110028] |
Tue, 28 December 2010 16:51   |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
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Nothing really new there, but this statement made me scratch my head:
" On the other hand, if the additional air pressure is used and the
additional weight is not carried, the 16-ply tire will be more
susceptible to impact breaks and irregular wear."
When I got through scratching, I'd decided I couldn't possibly agree
with that logic. I can agree that the higher the pressure in a tire,
the more susceptible it will be to impact breaks. But I can't agree
to the idea that the susceptibility will be greater with LESS weight.
Can anybody explain how that could be the case?
Ken H.
On Tue, Dec 28, 2010 at 5:25 PM, Rob Mueller <robmueller@iinet.net.au> wrote:
> G'day,
>
> I have been doing some research into tire load ranges and stumbled on to
> this from Bridgestone:
>
> http://www.bridgestonetrucktires.com/us_eng/answers/doctor_inflation.asp
>
> Interesting, eh?
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Ken Henderson
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www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] Interesting information about tire load range! [message #110052 is a reply to message #110034] |
Tue, 28 December 2010 20:35 |
Dennis S
Messages: 3046
Registered: November 2005
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Ken,
Perhaps the author is thinking that the higher tire pressure/light load results in a smaller foot-print. So any impact is greater/intensified on a psi basis -- as the impact is spread over less foot-print. My comment sounds redundant -- but perhaps you can make it out.
Dennis
an analogy -- partially filled ballon struck by bat versus highly inflated ballon -- which is more likely to burst?
| Ken Henderson wrote on Tue, 28 December 2010 16:51 |
Nothing really new there, but this statement made me scratch my head:
" On the other hand, if the additional air pressure is used and the
additional weight is not carried, the 16-ply tire will be more
susceptible to impact breaks and irregular wear."
When I got through scratching, I'd decided I couldn't possibly agree
with that logic. I can agree that the higher the pressure in a tire,
the more susceptible it will be to impact breaks. But I can't agree
to the idea that the susceptibility will be greater with LESS weight.
Can anybody explain how that could be the case?
Ken H.
On Tue, Dec 28, 2010 at 5:25 PM, Rob Mueller <robmueller@iinet.net.au> wrote:
> G'day,
>
> I have been doing some research into tire load ranges and stumbled on to
> this from Bridgestone:
>
> http://www.bridgestonetrucktires.com/us_eng/answers/doctor_inflation.asp
>
> Interesting, eh?
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Dennis S
73 Painted Desert 230
Memphis TN Metro
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| Re: [GMCnet] Interesting information about tire load range! [message #110057 is a reply to message #110034] |
Tue, 28 December 2010 21:09 |
Kosier
Messages: 834
Registered: February 2008
Karma: 1
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Ken,
If the tire has too much air pressure for the weight carried, it
will
lack the flexibility to absorb an impact and will be
ruptured.JMHO
Gary Kosier
77EII & 77PB
Newark, Ohio
----- Original Message -----
From: "Ken Henderson" <hend4800@bellsouth.net>
To: <gmclist@temp.gmcnet.org>
Sent: Tuesday, December 28, 2010 5:51 PM
Subject: Re: [GMCnet] Interesting information about tire load
range!
> Nothing really new there, but this statement made me scratch my
> head:
>
> " On the other hand, if the additional air pressure is used and
> the
> additional weight is not carried, the 16-ply tire will be more
> susceptible to impact breaks and irregular wear."
>
> When I got through scratching, I'd decided I couldn't possibly
> agree
> with that logic. I can agree that the higher the pressure in a
> tire,
> the more susceptible it will be to impact breaks. But I can't
> agree
> to the idea that the susceptibility will be greater with LESS
> weight.
>
> Can anybody explain how that could be the case?
>
> Ken H.
>
>
> On Tue, Dec 28, 2010 at 5:25 PM, Rob Mueller
> <robmueller@iinet.net.au> wrote:
>> G'day,
>>
>> I have been doing some research into tire load ranges and
>> stumbled on to
>> this from Bridgestone:
>>
>> http://www.bridgestonetrucktires.com/us_eng/answers/doctor_inflation.asp
>>
>> Interesting, eh?
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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| Re: [GMCnet] Interesting information about tire load range! [message #110080 is a reply to message #110028] |
Wed, 29 December 2010 07:28 |
Gary Casey
Messages: 448
Registered: September 2009
Karma: 0
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Senior Member |
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I agree with Dennis' reply, but I think the the grammar in the original
statement is a little misleading. I think they were saying that regardless of
the actual load, pumping a tire up to higher than the necessary pressure exposes
to the tire to the possibility of more damage - like Dennis said, the impact is
more localized. Another point hinted at in the article is that the actual load
capability is a function of pressure and the higher load rated tire is stronger
merely to allow a higher pressure. So lowering the pressure of an E-rated tire
to the max rating of a D tire makes it de facto a D tire. But, because of the
increased internal structure in the E tire, it will probably run hotter than the
D tire. Their recommendation is, don't buy a tire with a higher load rating
than you need, as it will likely run hotter and therefore be less durable than
the lower load rating tire. Example - for handling and ride considerations most
recommend pressures of 55 to 60 psi. The D tire is rated at 65 psi (I think -
right?) and the E tire is rated at 80 psi. The D tire is then a better choice
as you wouldn't ever need to run the E tire at 80 psi anyway. I don't know it
for a fact, but I've been told that the higher pressure tire will use a harder
tread compound so it isn't "squashed" upon contact with the road. Harder
compounds will almost always have less traction capability. YMMV
Gary Casey
Ken,
Perhaps the author is thinking that the higher tire pressure/light load results
in a smaller foot-print. So any impact is greater/intensified on a psi basis --
as the impact is spread over less foot-print. My comment sounds redundant --
but perhaps you can make it out.
Dennis
an analogy -- partially filled ballon struck by bat versus highly inflated
ballon -- which is more likely to burst?
Ken Henderson wrote on Tue, 28 December 2010 16:51
> Nothing really new there, but this statement made me scratch my head:
>
> " On the other hand, if the additional air pressure is used and the
> additional weight is not carried, the 16-ply tire will be more
> susceptible to impact breaks and irregular wear."
>
> When I got through scratching, I'd decided I couldn't possibly agree
> with that logic. I can agree that the higher the pressure in a tire,
> the more susceptible it will be to impact breaks. But I can't agree
> to the idea that the susceptibility will be greater with LESS weight.
>
> Can anybody explain how that could be the case?
>
> Ken H.
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| Re: [GMCnet] Interesting information about tire load range! [message #110135 is a reply to message #110028] |
Wed, 29 December 2010 17:03 |
pbrownsd
Messages: 56
Registered: December 2010
Location: Hayden,ID
Karma: 0
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Member |
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Pardon my newbie ignorance, but I'm confused by this thread. It seems the common recommendation is to run E rated tires. I've read pressure recommendations of 45-60psi(or so). Doesn't that run counter to this article? Shouldn't we be running D rated tires?
1976 Glenbrook
Hayden, ID
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| Re: [GMCnet] Interesting information about tire load range! [message #110543 is a reply to message #110540] |
Sat, 01 January 2011 22:19 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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Bob,
Are you saying the following statement is BS?
A 16-ply rated tire run at 14-ply rated pressure will only carry the weight
of a 14-ply tire, and in fact, due to difference in construction, may
actually run hotter while doing so.
Regards,
Rob M.
USAussie - Downunder
AUS '75 Avion-The Blue StreakTZE365V100428
USA '75 Avion-Double Trouble TZE365V100426
-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org
[mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of Bob de Kruyff
Sent: Sunday, January 02, 2011 2:43 PM
To: gmclist@temp.gmcnet.org
Subject: Re: [GMCnet] Interesting information about tire load range!
Pure anecdotal BS
--
Bob de Kruyff
78 Eleganza
Chandler, AZ
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: [GMCnet] Interesting information about tire load range! [message #110544 is a reply to message #110135] |
Sat, 01 January 2011 22:26 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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| pbrownsd wrote on Wed, 29 December 2010 17:03 |
Pardon my newbie ignorance, but I'm confused by this thread. It seems the common recommendation is to run E rated tires. I've read pressure recommendations of 45-60psi(or so). Doesn't that run counter to this article? Shouldn't we be running D rated tires?
|
Here is my take on this whole thing. After weighing my coach I found I could just get by with Load Range D tires. I do not know the difference in construction of Load Range D and Load Range E tires. I did at one time compare the a manufacturer's listed weight of a LRD and a LRE tire. They were the same. So that really makes me question the difference of what goes in them.
My conclusion was to run LRE tires (they are only about $3.00 difference in cost) and to inflate them to the recommended pressure based on the inflation chart for RVs. Actually I run them about +3 to +5 PSI over the published amount. I also check them for temperature (usually with my hand) every time I stop.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Interesting information about tire load range! [message #110561 is a reply to message #110543] |
Sun, 02 January 2011 10:32 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
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Senior Member |
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| Robert Mueller wrote on Sat, 01 January 2011 21:19 |
Bob,
Are you saying the following statement is BS?
A 16-ply rated tire run at 14-ply rated pressure will only carry the weight
of a 14-ply tire, and in fact, due to difference in construction, may
actually run hotter while doing so.
Regards,
Rob M.
USAussie - Downunder
AUS '75 Avion-The Blue StreakTZE365V100428
USA '75 Avion-Double Trouble TZE365V100426
-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org
[mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of Bob de Kruyff
Sent: Sunday, January 02, 2011 2:43 PM
To: gmclist@temp.gmcnet.org
Subject: Re: [GMCnet] Interesting information about tire load range!
Pure anecdotal BS
--
Bob de Kruyff
78 Eleganza
Chandler, AZ
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Rob--that was my reaction to the article overall. I'm not disputing the load carrying aspect but the heat generating part is unfounded.
Bob de Kruyff
78 Eleganza
Chandler, AZ
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| Re: [GMCnet] Interesting information about tire load range! [message #110563 is a reply to message #110562] |
Sun, 02 January 2011 10:39 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
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Senior Member |
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Just to add a little fun to the issue, one interesting aspect is that a tire cannot exert more unit pressure on the road than the actual inflation pressure regardless of the weight of the coach. So a tire inflated to 65psi, can only exert 65 psi on the road surface whether the load on that wheel is 2000# or 1500#. What happens is that the footprint on the road gets smaller or larger.
One reason U-Haul will run 110 psi on a tire is not only load related, but it will also reduce the tendency for hydroplaning.
Bob de Kruyff
78 Eleganza
Chandler, AZ
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| Re: [GMCnet] Interesting information about tire load range! [message #110569 is a reply to message #110028] |
Sun, 02 January 2011 11:35 |
Gary Casey
Messages: 448
Registered: September 2009
Karma: 0
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Okay, maybe I too have too much time on my hands. When I read the Bridgestone
article it made sense to me and matched what I've heard from other tire sources.
But of course, it depends on the specific example. I've looked at load ranges
D and E in the 225/75 size and come to the conclusion that at a lower pressure
the E probably runs no hotter than the D, as I can't detect any structural
difference, such as a stiffer sidewall. That may not be true of other sizes and
manufacturers. But I disagree with the hydroplane issue, just a little. The
tire patch with radial tires usually stays about the same width, but just gets
longer with lower pressure. The width of the tire patch is a big factor in
hydroplaning. Wider is bad. A longer tire patch is good in that it gives more
time for the rubber to squeeze down through the water. I would not run a higher
pressure than is required just to prevent hydroplaning - I don't think it will
work.
Gary Casey
Oh, and don't rent a U-Haul trailer to me - the first thing I do when out of
sight is to lower the tire pressures to match the load I'm carrying. Much
better ride for whatever is in there. And then I usually forget to pump them
back up when returning. Oh, well.
Just to add a little fun to the issue, one interesting aspect is that a tire
cannot exert more unit pressure on the road than the actual inflation pressure
regardless of the weight of the coach. So a tire inflated to 65psi, can only
exert 65 psi on the road surface whether the load on that wheel is 2000# or
1500#. What happens is that the footprint on the road gets smaller or larger.
One reason U-Haul will run 110 psi on a tire is not only load related, but it
will also reduce the tendency for hydroplaning.
--
Bob de Kruyff
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| Re: [GMCnet] Interesting information about tire load range! [message #110571 is a reply to message #110569] |
Sun, 02 January 2011 11:56 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
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Senior Member |
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""A longer tire patch is good in that it gives more
time for the rubber to squeeze down through the water. I would not run a higher
pressure than is required just to prevent hydroplaning - I don't think it will
work.
""
The hydroplaning benefit is not due to the change in footprint but rather the higher unit pressure on the road surface. As far as tire pressures on U-Haul trucks and trailers, you can imagine that with 100,000 units of each on the road, we need to have tire pressures that comprehend intended as well as non intended usage.
Bob de Kruyff
78 Eleganza
Chandler, AZ
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| Re: [GMCnet] Interesting information about tire load range! [message #110595 is a reply to message #110569] |
Sun, 02 January 2011 19:02 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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The first I ever heard of "hydroplaning" was in the early '60's, while
flying F-101B's out of Charleston AFB, SC. USAF introduced us to the
idea based on research which showed that if water was standing to a
depth of the tire tread or greater, at a speed of approximately 9
times the square root of the tire pressure (9*sqrt(psi)), there would
be NO friction. That is, the lifting effect of the "bow wave" would
equal the weight of the aircraft. There was never any mention of tire
width, though it may be one of the parameters ignored in offering an
easy to remember, quick to calculate simplification.
For our 250 psi tire pressure,that said a landing speed above 145 mph
was to be avoided. Since our touchdown speed was about 140 knots (160
mph), we paid attention when the tower advised us of standing water.
I don't know how well the formula applies at more reasonable speeds,
but it says a 65 psi GMC tire will hydroplane at about 72 mph.
Ken H.
On Sun, Jan 2, 2011 at 12:35 PM, Gary Casey <casey.gary@yahoo.com> wrote:
> ... The width of the tire patch is a big factor in
> hydroplaning. Wider is bad. A longer tire patch is good in that it gives more
> time for the rubber to squeeze down through the water. I would not run a higher
> pressure than is required just to prevent hydroplaning - I don't think it will
> work...
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] Interesting information about tire load range! [message #110605 is a reply to message #110595] |
Sun, 02 January 2011 20:14 |
Kosier
Messages: 834
Registered: February 2008
Karma: 1
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Senior Member |
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Ken,
Good calculations! About 20 years ago, I was going up to Moms
for Christmas in the GMC. Thinking about Mom's pecan pie and
running about 70-75. Suddenly the motor sounded funny and as
I looked down, the speedo was taking a big swing to the right.
I lifted my size 12 and waited to lose some speed.
Unfortunately,
Old Sonar Ears heard it also and raised hell about my driving so
fast. Sort of the pot calling the kettle black. Not my first
mistake
of that sort, or probably not the last.
Gary Kosier
----- Original Message -----
From: "Ken Henderson" <hend4800@bellsouth.net>
To: <gmclist@temp.gmcnet.org>
Sent: Sunday, January 02, 2011 8:02 PM
Subject: Re: [GMCnet] Interesting information about tire load
range!
The first I ever heard of "hydroplaning" was in the early '60's,
while
flying F-101B's out of Charleston AFB, SC. USAF introduced us to
the
idea based on research which showed that if water was standing to
a
depth of the tire tread or greater, at a speed of approximately 9
times the square root of the tire pressure (9*sqrt(psi)), there
would
be NO friction. That is, the lifting effect of the "bow wave"
would
equal the weight of the aircraft. There was never any mention of
tire
width, though it may be one of the parameters ignored in offering
an
easy to remember, quick to calculate simplification.
For our 250 psi tire pressure,that said a landing speed above 145
mph
was to be avoided. Since our touchdown speed was about 140 knots
(160
mph), we paid attention when the tower advised us of standing
water.
I don't know how well the formula applies at more reasonable
speeds,
but it says a 65 psi GMC tire will hydroplane at about 72 mph.
Ken H.
On Sun, Jan 2, 2011 at 12:35 PM, Gary Casey
<casey.gary@yahoo.com> wrote:
> ... The width of the tire patch is a big factor in
> hydroplaning. Wider is bad. A longer tire patch is good in that
> it gives more
> time for the rubber to squeeze down through the water. I would
> not run a higher
> pressure than is required just to prevent hydroplaning - I
> don't think it will
> work...
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