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Old 12-30-2010, 10:53 PM   #57
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It is disappointing to see how new ideas are handled in this forum. That probably explains why I really don't bother contributing very often. Offthewall is addressing his concerns in a somewhat logical manner and deserves a response. Those who chime in with one line taunts really just show their ignorance. For example: anyone with an undergraduate math degree understands the significance of the word 'orthogonal'.

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Originally Posted by offthewall View Post
This is my issue with your method. You have NO actual data as to what that "optimal" warm pressure is. You are making unsubstantiated guesses as to what that pressure is...
Fair enough. We don't get the data we need from RV tire manufacturers.

Race tires? No problem. Warm tires are all that matters, and race teams know how to read warn pressure charts, so that's the data they get. Teams must still take sample readings like I do to get the accurate parameters for their vehicle in different conditions. But as you suggest, once you have a performance curve, you expect your scatter plot of readings for a given set of parameters will fit the polynomial function provided by the manufacturer.

After several runs with a TPMS you will get a nominal set of warm readings that ARE CORRECT FOR YOUR VEHICLE UNDER YOUR NORMAL DRIVING CONDITIONS. I would apply regression analysis if I thought the numbers were inconsistent or if I suspected there were more variables involved. The truth is: a 10% rise +/- 1% after 20 minutes of driving over the cold temperature reading pretty much works across all conditions I encounter. Sensor jitter probably accounts for the 1% variation. This is the warm pressure number I use. Your results will be different.

Any cold pressure chart from a tire manufacturer assumes an average pressure increase for an average vehicle under average conditions. That estimate is incredibly inaccurate across all possible vehicles and conditions. My so called empirical readings, taken over a large enough set of samples and conditions, are many times more accurate.

When some of you suggest I am 'guessing at numbers', you should realize that cold pressure tire charts from manufacturers have a lot more guess work involved.

In the end, I don't think many of you understand the power of a TPMS and what you can do with it. In my line of business, we often say: "You can't manage what you don't measure." With a TPMS you can manage your coach much better than ever before. That doesn't seem to interest some of you.

Ciao.
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Old 12-31-2010, 08:19 AM   #58
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This is a RV version of the classic Physics problem - What happens when an immovable object meets an irresistible force?

The answer is -- many repetitive posts displaying increasing frustration on both sides.

Let's face it, folks. Neither side is going to persuade the other.

My own take is that in the litigious society we live in, the tire manufacturers would be in full CYA mode if they thought there was any safety issue with the instructions they give.

But no one is going to change deeply held convictions on a Forum.

Time to move on to more interesting issues - in my humble opinion, of course.
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Old 12-31-2010, 11:16 AM   #59
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...Offthewall is addressing his concerns in a somewhat logical manner ...
At least I'm "somewhat" logical.

I still don't understand how you decide that a given pressure deservers bleeding. Aren't those instances where you decide to stop and bleed air just more points on your pressure rise graph? Maybe there is a valid reason those pressures rose other than due to your assumption that they just don't fit your normal pressure rise graph. As a former senior research scientist (yes that was my official title ), we knew throwing out "outliers" was a slippery slope.

I've noticed for instance that my fronts on my previous Class C rose considerably when going through bumpy weaving highway construction areas (ie rt 287 near White Plains NY), then dropped back down to normal warm readings (OMG I'm using your terms ).

Your method is anything but simple as you originally stated but rather convoluted, complicated and probably just plain wrong. I believe most of us would be better served by following the manufactures guidelines. Fill to proper COLD pressure in the morning and leave it be. Check again the next morning and adjust if required. Simple, accurate, safe. Use your TPMS to Monitor pressures and temps during the day to catch any problems early like sudden rises in temp or falling pressures. Otherwise just drive and adjust them again in the morning if required.
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Old 12-31-2010, 12:15 PM   #60
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Quote:
Originally Posted by UltraKen View Post
This is a RV version of the classic Physics problem - What happens when an immovable object meets an irresistible force?

The answer is -- many repetitive posts displaying increasing frustration on both sides.

Let's face it, folks. Neither side is going to persuade the other.

My own take is that in the litigious society we live in, the tire manufacturers would be in full CYA mode if they thought there was any safety issue with the instructions they give.

But no one is going to change deeply held convictions on a Forum.

Time to move on to more interesting issues - in my humble opinion, of course.
Ah but the debate itself is entertaining from a participation and spectator point of view
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Old 12-31-2010, 02:38 PM   #61
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Without looking at a dictionary, who knows the definition orthogonal? I'm surveying how many people on this forum are ignorant.

Jim E
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Old 01-01-2011, 12:05 AM   #62
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Heh.. A right angle...

made me laugh when you said it too
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Old 01-01-2011, 07:09 AM   #63
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Quote:
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Without looking at a dictionary, who knows the definition orthogonal? I'm surveying how many people on this forum are ignorant.

Jim E

Ignorant because they don't know one term from a specialized field?

We all have our individual knowledge bases. Should we call you ignorant because you don't have that specialized knowledge?

BTW, are you ignorant or can you demonstrate knowledge of the Pulfrich Effect without looking it up?

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Old 01-01-2011, 07:30 AM   #64
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Without looking at a dictionary, who knows the definition orthogonal? I'm surveying how many people on this forum are ignorant.
Jim E
I don't know how many are ignorant.
But I have found out from this tread, which ones that think they are smart A** Holes
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Old 01-01-2011, 10:08 AM   #65
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UltraKen,

Lighten up, go back and look at post #57.

Jim E
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Old 01-01-2011, 03:18 PM   #66
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UltraKen,

Lighten up, go back and look at post #57.

Jim E

Which of my two posts are you referring to? Are you ignor....er...unaware of the quote function?

Seriously, I made two points. One is that the discussion is going nowhere except to become more heated. The other is that it seems impolite to call people ignorant because they may, or may not know a term.

By the way, what do you think is written in #57 that addresses either of my posts?
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Old 01-01-2011, 06:25 PM   #67
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Ultraken,

Quote:
Those who chime in with one line taunts really just show their ignorance. For example: anyone with an undergraduate math degree understands the significance of the word 'orthogonal'.
This is what i was referring to.

Jim
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Old 01-01-2011, 06:33 PM   #68
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OK, I looked it up onGoogle and according to Wikipedia orthogonal means perpendicular and if so why not use the word many of us under educated would understand?
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Old 01-01-2011, 07:50 PM   #69
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Hey do any of you guys overnight at Walmart parking lots?


I run my tires at the recommended inflation for gross weight.... being anal about tire pressures wont help you when you run over a nail.
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Old 01-01-2011, 07:51 PM   #70
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How about DRH? While you think about it I'm going to go let some air out of my tires.
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