Just some of the stupid things I see

I hate to disagree, but the max pressure posted on the side wall is the COLD inflation pressure. Tires are designed to carry whatever the increase in pressure may be from running, friction and ambient air temps that are created, and result in working pressures higher than the COLD max pressure on the sidewall.

 

I just want to know when you plug in a guy like this into the computer system, if a special buzzer/bell, flashing banner go off and says "we have a winner!"

Do any of the folks you tell us about qualify for an end of the month MEGA winner prize, for having the most things wrong?

 

Here's the winning answer!

And "cold" means whatever the ambient temperature is after the tire has been sitting awhile - I've seen 4 hours mentioned.

 

Ditto on the "Box of chocolates"!

Some stops are very smooth.

Every once in a while you find a NUT!

 

And this is why the arrest ratio is so much higher for agencies that work more traffic than others do. It's also why their officer mortality is higher.

 

...but who came up with that criteria? 393.75(a)(3) only says "flat", which is nothing more than a deflated tire. To determine the extent to which that tire is deflated, 393.75(h)(1) should be consulted because it is the ONLY reference within the actual regulations as to the minimum required tire pressure.

Issuing a "50% of max inflation = OOS" mandate has nothing to do with safety, because a tire inflated to less than 50% of the maximum inflation could still very well be properly inflated as per the tire manufacturer and therefore would be perfectly safe to run and absolutely allowable under 393.75(h)(1). Essentially, such a mandate is idiot-proofing enforcement, assuming the officers charged with enforcing the regulations are too lazy or somehow otherwise incapable of getting their hands on the manufacturer's recommended load & inflation pressures. In this day and age of laptops and internet access in your squad car, there is no excuse for not being able to get the load & pressure information on any tire you have a question about.

Now I fully understand not buying the "it's properly inflated" argument from a driver who has 17 tires inflated to 95-100 psi...and 1 tire that is 50 psi. However, if EVERY tire on the truck is properly inflated as per the manufacturer's recommendation, it should be viewed differently....even if that pressure doesn't quite reach the 50% of max threshold....because it is absolutely in compliance with 393.75(h)(1).

Back to my tires, in the chart, it stops with the load & pressure recommendations for 38,880 pounds on the tandem axle. That would be overweight, so nobody (without a permit or other special circumstance) is going to be running that sort of weight. Therefore, inflating the tire to that point would still be overinflated for a lower loaded weight. If you look at the chart, for every 800/axle increase (1600/tandem) in load placed on the tire, the recommended tire pressure goes up by 5 psi.

38,880 - 34,000 = 4,880
4,880 / 1,600 = 3.05
3 * 5 psi = 15 psi
75 psi - 15 psi = 60 psi

I'm sure if someone wrote Michelin, they would provide inflation tables for lower weight loads...they just aren't on the website.

Going back to your pickup truck tire example where you run 44 psi, think about this for a minute: PSI stands for pounds per square inch. 12-14 psi in a lawnmower tire barely makes a sound when you puncture a tire....stab a knife into the sidewall and it won't be much more noticeable than a mouse farting into the wind. However, puncture a pneumatic tanker while it is holding the same 12-14 psi and it can kill you. I wouldn't even recommend trying to open a lid if there's as little as 2-3 psi still in the tank, because that top hatch is 19" across and has a surface area of 284"...and with 2-3 psi pressing on that lid, that is enough to lift a 568 to 852 pound object resting on the top of the lid. Pull the 4" cap off the product line when there is 2-3 psi in the tank, and with only 13 square inches of surface area, it only has 26 to 39 pounds of force behind it.

The same rings true for the difference between large truck tires and those tiny little tires on your pickup truck. A similar pressure per square inch, spread out over more square inches, is capable of supporting a lot more weight. With an empty trailer, I have twice as much weight on my drives as your full size pickup...and twice as many tires, too. Taking into account the difference in surface area, my truck's drive tires could actually be inflated to LOWER pressures than your pickup truck tires when I don't have a load in the trailer.


Perhaps I'm over-thinking things a little too much, but there is an obvious flaw in the CVSA's interpretation of the FMCSA regulations.

There was nothing to "disagree" with. Nobody here claimed it wasn't the "cold inflation pressure". There is even a formula in the regs to determine the pressure rise in a "warm" tire in order to figure out what the approximate "cold" pressure would be. (see 393.75(h)(2)) Even that, though, is flawed, as it makes no consideration as to the load being carried by the tire. A tire carrying the maximum legal load will run hotter than a tire on an empty truck driving the same speed over the same duration of time.

 

I think your making too much of this Pedrgree.
Inflate your tires as you deem necessary, and don't worry about the petty stuff.

 

I got one......

Can I get cited for having a bad tire in my tire rack?

The reason I ask is cause I blew a tire a few weeks ago. Stopped and had it changed. I told them I'd take it with me and I put it in my tire rack. Now I own everything so its my business what I'm gonna do with it but this kids started telling me I could get cited for having that junk tire in the rack. I tried my best to not laugh. At first I thought this was something the TS was doing to scare drivers into paying to get rid of it. I've asked around but have never had the chance to ask DOT about it.

If the answer is Yes would you please give the reference code for the rule?