Tire pressure for hwy driving

Wait wait hold up, your telling me the door close button doesn't actually close the door faster.... son of a bitch

 

Let’s not let science cloud the issue.

 

Let's recap shall we--as I said, the chalk test gives you a pressure starting point and then fine adjustments can be made based on actually measuring wear across the tire tread at each tire rotation interval. This process results in maximum contact patch engagement across a wide range of driving conditions for a specific vehicle and individual's driving style/environment. My experience over the last 25 years using this simple and proven technique is that the fine adjustments seldom vary by more than a couple of psi from that initial chalk test starting point. This is not opinion nor is it something read on the internet. You can't fool a tread depth measuring device.

BTW, I would suggest you re read your first paragraph in your post #19. In the first couple of lines you state that this test is worthless due to rotational distortion of the tire at speed and then the second half of the same paragraph state that our Tacoma tires stay flat at speed--can't have it both ways!!

As before, your technique for optimizing tire pressure depends on your objective. Mine is to find a pressure that optimizes a balance between tread life, vehicle traction, and mileage. No NASCAR nor NHRA for my Tacoma!! See ya!

Cheers,

db

 

It can't be a starting point when there is no information to gain to begin with. The 'data' that you receive from this 'test' is not relevant to your objective of finding your ideal air pressure.

As for the statement regarding distortion, you are confusing two separate variables by trying to combine them together. Tires will distort as rotation increase. That is fact. There are plenty of pictures on the internet to support that. Steel belted tires by design will keep the tread portion flatter with a higher variation in air pressure than bias ply tires of old (which is where this chalk test originated). What this means is that using your chalk test, you will likely find a flat contact patch doing this test equally at 5psi as you do at 40 psi. That would not be true using a bias ply tire. The more you compromise the variables, the less meaningful of your output data becomes.

These are only two variables of this test. There are so many more things to consider that the results of this 'test' render any chalk findings completely useless.

One other simple observation that renders this test useless since you mention traction is that you are only looking at the section width contact and not the circumferential contact. There is a reason we air down when we go off road and using your theory that you measure how flat you can get this section width with using chalk, you shouldn't have to air down because you have already found that perfect air pressure that keeps the center of your tread in contact with the road.

We could go on and on here pointing things out. It really doesn't make any difference because the facts are supported by science not theory. The chalk test is little more than a back woods novelty.

 

Sungod, Your position is counter to the experience of literally thousands of people, myself included, who have used and recommend this technique to successfully determine optimum tire pressure for our individual vehicles and driving styles. Don’t believe me—take a look at how many different vehicle forums recommend this technique and note that there are few, if any (other than yourself) who disagree:


https://www.jlwranglerforums.com/forum/threads/what-psi-should-i-run-do-a-chalk-test-to-deter


Special attention to comment #14 in the above thread.


https://www.tundras.com/threads/tire-pressure-chalk-test-how-to-guide.2114/


https://www.4runners.com/threads/tire-chalk-test-how-to-guide.1290/


The next one is from a well known vehicle accessories dealer who caters to all terrain vehicle owners and is one of many who recommend this as one method to find optimum pressure;


https://www.4wheelparts.com/a/tire-wheel-package-guide-tire-pressure-checker


Still disagree, go to the National Tire Safety Institute and do some research.


Still disagree, do some research at the Discount Tire Direct forum and/or the Tire Rack forum.


How can so many be wrong and only one be right???


BTW, your comment in the second paragraph states that if you chalk test steel belted tires you would “likely find a flat contact patch … equally at 5 psi as you do at 40 psi.” This statement is not true—-anyone who has done this test knows that relatively small changes in tire pressure are very apparent in the chalk wear pattern. To illustrate please see the attached for the correct application of the technique and the affect pressure changes make:


https://www.youtube.com/watch?v=MIvbFgrH0IQ


And reference your comments on airing down for off road—you air down to soften the ride, to avoid puncturing highly inflated tires on sharp objects, and to improve traction by allowing the tires to conform to irregular terrain. However, that is irrelevant as I would direct your attention to the title of this thread “Tire Pressure for Highway Driving”!


And with that I am moving on!


Cheers,

db
"Those who fail to learn from history are doomed to repeat its mistakes!"

 

"Well i'll be damned. It is on the internet so it has to be true!" Look, you can believe what you want. I stand behind the science. As I stated it is one of those things that doesn't hurt anything so people accept it. The internet is full of those stories. You can ask each an every one of those posters about the science behind what they are saying and they will all say the same thing "I don't know, I found it on the internet so I assumed it to be accurate because someone else posted it."

This phenomenon isn't uncommon. Let's not forget that there was a show called "Myth Busters" that ran several season to test things just like this.

 

Is this a DF?

 

The problem is that you are measuring pressure in pounds per square inch.....I mean, really?

The real question is why aren't you measuring it in torr?

I have my tires inflated to 1966 torr. That is what you should be shooting for.

 

Inches of mercury would be more accurate and provide balance beads when spilled in the tire.....

 

I see what you did there....you crafty fucker.

You're wrong of course, Torr is the obviously superior unit for measuring tire pressure.

I strongly suggest you and I hijack this vital thread no further. We both know that the ensuing debate would be way above the heads of these peons.

 

So true,

We need a thread to get smoldering so there is some excitement. Been kinda blah this week.

I think we should use water pressure and depth calculations for tire pressure....

 

Filled mine to 35 cold. Florida heat or a few mins of driving and they are at 37. Feels right

 

30 is fine for the OEM tire; why would you think otherwise?

Not directed at you, but I find it hilarious TW in one breath will claim, Toyota put 'those' fluids in there for miniscule mileage improvement.
Then in the next breath claim Toyota PSI specs are for comfort...

 

Falken WP AT3 Street Pressure
Recently completed my 3rd 5k mile tire rotation/tread wear measurement at D.T. We made a slight adjustment in pressure at 5k and again at 10 k over our baseline (total of +2-3 psi) but at 15k no adjustment necessary as we have an even wear pattern over the tread surface. Looks like 36-37 psi is gold for my truck and driving habits. This on a TRD OR SB Crew 4x4. The only extra weight on the truck are side rails/steps and a bed cover. Falken WP AT3 in 265/70-17. FYI
Cheers,

db

 

SL or LT?

 

Sorry--should have included that

SL

Cheers,

db