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Old 03-05-2015, 10:37 AM   #57
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Originally Posted by r carl View Post
I've only seen excuses.
OK I accept the challenge. You give me a specific question with all the relevant facts and I will offer my opinion.

It may help if I knew your profession so I can understand your view on product quality and reliability.
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Old 03-05-2015, 10:56 AM   #58
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Who here disagrees that a tire with internal damage resulting from being driven under inflated usually always displays external evidence of this damage via bulges, lumps, uneven sidewalls, or knots on the sidewall or tread area?

In short, the damage to the interior of a tire USUALLY becomes visible on the exterior.

The application of common sense sense goes a long way.

I can't remember the last time I was stuck on the side of the road with a failed tire or even a flat. Perhaps 20 years or more?

Part of this is what is called "luck", but part of this is paying attention to my tires.


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Old 03-05-2015, 11:15 AM   #59
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You think they are under inflated?
Lets try a different approach to see if we can help you understand what is meant by under inflated.

"Under inflated" means less air pressure than is needed to carry the load.

For motorized vehicles we see than if we assume your axle weights are equally split side to side, each front tire is loaded to 4,800/2 or 2,400#. As Capri has pointed out your 225/70R19.5 LR F inflated to 60 psi has 2615# capacity so your have EXCESS load capacity of 215# for each tire
You are not under inflated.

Lets look at the rear position where I assume you are running duals.
Again as Capri said "75 psi rear has a load carrying capacity of 2,860# (dual)" but your actual load, again assuming exact 50/50 split side to side is 7800/4 or 1,950# per tire. Your load capacity for the 4 rear tires totals 11,440 but you are only loading them to 7,800# so you have Excess Capacity of 3,600# total on the rear axle.
Again you are not under inflated.

An example of under inflation might be when someone running 225/70R19.5 LR F inflates the front tires to 65 psi which according to the Load/Infl tables indicates 2,755# load capacity for each tire but has loaded the vehicle such that the front axle measures at 6,000#. In this case the actual load EXCEEDS the capacity by 490#. In this case the tires are "under inflated".

Hope that between Capri's answer and my example you now understand what is meant by under inflation.
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Old 03-05-2015, 11:16 AM   #60
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Originally Posted by J. Morgan View Post
I can't remember the last time I was stuck on the side of the road with a failed tire or even a flat. Perhaps 20 years or more?

Part of this is what is called "luck", but part of this is paying attention to my tires.
I made my first tow in the late 60's. So far (knock on wood) I have not had a flat tire on any trailer I have owned. On cars and trucks I have occasionally, but not on my trailers.
I have found metal objects stuck into treads and had them repaired when needed. I would say part of it is "luck", but the larger part is being vigilant about checking tire pressure and inspecting tires before, during, and after each tow.
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Old 03-05-2015, 11:19 AM   #61
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Originally Posted by J. Morgan View Post
Who here disagrees that a tire with internal damage resulting from being driven under inflated usually always displays external evidence of this damage via bulges, lumps, uneven sidewalls, or knots on the sidewall or tread area?

In short, the damage to the interior of a tire USUALLY becomes visible on the exterior.

The application of common sense sense goes a long way.

I can't remember the last time I was stuck on the side of the road with a failed tire or even a flat. Perhaps 20 years or more?

Part of this is what is called "luck", but part of this is paying attention to my tires.


1/2 Ton 4WD Truck, 72 Sovereign Hensley Arrow

"usually always"

Careful SteveH and r_Carl don't like these less than definitive yes or no clear cut answers.
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Old 03-06-2015, 05:56 AM   #62
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Originally Posted by A W Warn View Post
For my trailer tires use these (lowest load to highest load)

For tire # 1 of 4:
Tire size = ST225/75-R15 load range E
Tire load = 1,600 lbs
Tire inflation = 60psi

For tire # 2 of 4:
Tire size = ST225/75-R15 load range E
Tire load = 1,800 lbs
Tire inflation = 60psi
Let's do some more math.

An ST225/75R16 inflated to 60 psi has a load carrying capacity of 2380#.

I like a tire not operate at more than 85% of its rated load, so my recommendation would be not to load the tire more than 2023#.
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Old 03-06-2015, 06:59 AM   #63
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OK I accept the challenge. You give me a specific question with all the relevant facts and I will offer my opinion.

It may help if I knew your profession so I can understand your view on product quality and reliability.
I've spent yrs welding pipeline and in a few nuclear power plants. I'm a Virgo so I'm inherently a perfectionist.
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Old 03-06-2015, 07:09 AM   #64
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Originally Posted by Tireman9 View Post
Lets try a different approach to see if we can help you understand what is meant by under inflated.

"Under inflated" means less air pressure than is needed to carry the load.

.
Who's (we) and I've read a post from one of the 2 experts here in the past that said less than 80% of the sidewall max pressure is a tire under inflated.
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Old 03-06-2015, 07:15 AM   #65
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Quote:
Originally Posted by J. Morgan View Post
Who here disagrees that a tire with internal damage resulting from being driven under inflated usually always displays external evidence of this damage via bulges, lumps, uneven sidewalls, or knots on the sidewall or tread area?

In short, the damage to the interior of a tire USUALLY becomes visible on the exterior.

The application of common sense sense goes a long way.

I can't remember the last time I was stuck on the side of the road with a failed tire or even a flat. Perhaps 20 years or more?

Part of this is what is called "luck", but part of this is paying attention to my tires.


1/2 Ton 4WD Truck, 72 Sovereign Hensley Arrow
Maybe tires nowadays are considered damaged if you let the air out and refill them while they are still on the vehicle.
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Old 03-06-2015, 11:33 AM   #66
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Who's (we) and I've read a post from one of the 2 experts here in the past that said less than 80% of the sidewall max pressure is a tire under inflated.
Can't speak for Capri but If you can point to where I said that running 20% less than the tire max load as molded on the sidewall was considered "flat" for warranty purposes, I will go and correct that statement.

I have seen statements from tire companies to the point of defining a tire as "flat" when it has lost more than 20% of its air. I interpret this to mean the air pressure needed to carry the actual load on the tire.
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Old 03-06-2015, 11:37 AM   #67
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I've spent yrs welding pipeline and in a few nuclear power plants. I'm a Virgo so I'm inherently a perfectionist.
Cool.

Could you tel me the correct Amp setting when welding 6" diameter Schedule 80 pipe?

The answer needs to be in the form of...
"The correct setting to weld 6"diameter Schedule 80 pipe is xxx Amps."

Remember no wishy washy answers such as "Sometimes..." or "If you are welding using.....". etc.
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Old 03-06-2015, 01:00 PM   #68
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Repaired tires

I now have two repaired tires on my 2014 RAM 1500. They were repaired at Discount Tire. I was alerted to the first tire going flat by the TPMS as I was turning the corner into my shop. It was a nail in the right front. The second, also on the right front after tire rotation, I heard the leak because it was wet. This time it was a flat head drive bit. The TPMS gives me confidence these tires will last until I change them because I know they weren't run under inflated.
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A week ago I purchased the "certificates" from Discount Tire to cover non repairable damage. Since all the houses around here are getting new shingles from last spring's hail storm there seems to be a lot of tire punctures.
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Old 03-06-2015, 01:21 PM   #69
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Cool.

Could you tel me the correct Amp setting when welding 6" diameter Schedule 80 pipe?

The answer needs to be in the form of...
"The correct setting to weld 6"diameter Schedule 80 pipe is xxx Amps."

Remember no wishy washy answers such as "Sometimes..." or "If you are welding using.....". etc.
The type and size of rod will determine that.
1/8 7018 will be around DC 115amps
I use a Lincoln SA200 so I don't know the amps.
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Old 03-06-2015, 01:34 PM   #70
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Originally Posted by CapriRacer View Post
Let's do some more math.

An ST225/75R16 inflated to 60 psi has a load carrying capacity of 2380#.

I like a tire not operate at more than 85% of its rated load, so my recommendation would be not to load the tire more than 2023#.
Thanks for all of the information you provide!

After 3+ years of owning these tires, I sent another (2nd or 3rd) request for a load/inflation chart to the Towmax customer service dept. I finally got it today!

The number you gave me was exactly what the chart says. According to this chart, I could lower the pressure in my trailer's tires to ~36-37 lbs before they would be underinflated. (assuming 100% of the published load capacity is underinflated, the point at which the pressure does not support the load) That's good to know!

Another thing I learned: The manufacturer's data plate on my Safari says to inflate to 50 PSI. The chart says that pressure in my tires will support 2,150 lbs at 50 PSI. Using the 85% rule that you suggested indicates the tires should be good up to 1,827 lbs at 50 PSI suggested by Airstream, a perfect match.

Though, I will continue to inflate to 60 PSI to have that extra capacity.

Thank you for the clarifications!
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