Well, I think I know what our towing problem is!

I am sure the OP has the idea by now, and the remarks are becoming personal in nature, so I am closing this thread.
Barney

DiskDoctr wrote:


Quote: "The Commercial Vehicle Safety Alliance is currently exploring how to define underinflation for enforcement purposes. CVSA has already settled on a definition of a "flat" tire: 50% of the max cold inflation pressure stamped on the sidewall of the tire, e.g., 60 psi in a tire stamped for its max load at 120 psi inflation pressure."

That will work until the first ticket is written and the judge is shown that under certain loads with certain tires it's manufacturer approved. If the OEM specs approve the pressure for the load them by definition it's not flat.

Many commercial tires have minimums that are above 50% of the max cold inflation pressure, so for commercial enforcement that would be correct most of the time.

Many LT tires allow pressures at 50% of max cold pressures, or below.

Good article, did you read all of it?

DiskDoctr wrote:

ExxWhy wrote:


Can you point us to something from tire mfgs or vehicle mfgs that documents never to run your tires at less than 90% of the sidewall max number? Everything I have read says otherwise.

Actually, the point is 50% inflation, using the sidewall printed values, is not acceptable under load.

It was a different poster who claimed that 90% inflation could never be safe and would never be done by any tire store. The same poster who claims 50% inflation is not only okay, it is the 'right' way and everyone should be doing it :R

According to who, you?

According to the two sources I gave you it is acceptable for a certain load. You keep saying load, but have yet to define the load. Is it 1500, 2000, 3000?

I am still not sure how you are not understanding simple published specs by manufactures of vehicles and tires alike.

My guess is you are so full if your opinion that you are unwilling to look at data from someone else.

There is only one opinion on inflation pressure being presented in this thread DiskDoctr, and it's yours. The rest is based on OEM specs.

Nice post ExxWhy, there is just no convincing some people.

Pitch, it's very possible a tire is bad but based on the reported pressure and empty state of the truck it's seems more likely they are simply overinflated. It would be easier to drop them to the proper pressure for the load and see how they react.

I'm sure that the OP has run out the door screaming by now due to the "debate" that is raging.
How about the possibility that one or more of the tires is just bad as in a slipped or broken belt? Or the possibility that one of the rims was bent while demounting the old or by improper torqueing or the hub face has debris on it preventing the assembly from mounting properly. I once bought new tires and they were wobbly like a MF tire guy had failed to put the lug nuts on the right rear.
Some of us would rather sit on high and bestow all the underlings with our vast knowledge instead of answering the op,s question.

DiskDoctr wrote:

ah64id wrote:
I see max load and max pressure, what about at a load less than max?

Have a link for a lower load? On wait, I already posted that for you.

Yeah tires do have ratings, all you seem to care about is max. I gave you a link to a chart for loads less than max, made by a tire company and similar to many other tire companies charts, and you ignore it.

If this is how you are with tires I'd hate to see you react whe the fuel gage hits 1/2......

I would say it for the last time, but somehow I don't think it will get thru to you.

These are not MY opinions, all the data I am presenting is based on published data from vehicle and tire manufacturers. The only thing you are giving is an opinion, one that doesn't hold any water when presented with the facts.

Heck I even showed you the door jam sticker showing a 40 psi recommended pressure on an OEM LRE tires rated at 80 psi max, what more is there to comprehend? It's not imagination, it's fact pure and simple.

In your, and only your, opinion running a tire at a pressure appropriate for its load is under inflated if that's less than 90% of max. You are the first one I have ever read that statement from. It's NOT under inflated, it's called PROPER INFLATION.

Firestones issue was under inflation, but only because it wasn't enough air for the weight and NOT because it was less than 90% of MAX.

Quote: "The Commercial Vehicle Safety Alliance is currently exploring how to define underinflation for enforcement purposes. CVSA has already settled on a definition of a "flat" tire: 50% of the max cold inflation pressure stamped on the sidewall of the tire, e.g., 60 psi in a tire stamped for its max load at 120 psi inflation pressure."

Source: http://www.truckinginfo.com/channel/drivers/article/story/2013/07/what-exactly-constitutes-an-underinflated-truck-tire.aspx

FMCSA and CVSA and multiple DOT enforcement are pretty credible sources. Granted, passenger vehicles are seldom (ever?) cited for under inflated tires, so we have to look at the professional references.

Interesting article, too bad you quit reading once you saw the tidbit you wanted to see. Here's a quote a little further down the page. "DOT inspectors won't usually check tire pressure unless they suspect a problem, like the tire looks soft," Fisher said. "The problem is they have nothing to go by except what's stamped on the tire. To determine the proper inflation pressure of a tire, they need to know the temperature of the tire and the load on the tire. All that comes into play in determining the proper inflation pressure of a tire."

Article goes on to say this at the end. TMC and CVSA are still working on this, and a solution doesn't seem close at this point. But maybe this information can help you in a DataQ challenge. Is that 70-psi tire really underinflated?


Load & Inflation Table examples
Michelin 275/80R22.5

Steer 5,980 @ 105 psi; 6,175 @ 110 psi

Drive/trailer 4,770 lb single @ 75 psi

Bridgestone 295/75R22.5

Steer 5980 @ 105 psi; 6175 @ 110 psi

Drive/trailer 4540 lb single @ 80 psi



Goodyear 295/75R22.5

Steer 5,980 @ 105 psi; 6175@110

Drive 4,690 @ 75 psi

How about this?

Michelin Inflation

Or this

Goodyear Inflation

Or this

Bridgestone Inflation

Or this

Toyo Inflation

If you look starting on page 7 of the Toyo PDF, it gives the guidlines for determining tire pressure for your particular application. Starts with the door placard and goes from there to the inflation charts for your particular tire size.

The common denominator in all this is there is a specific PSI that is appropriate for various tire sizes and loads. Why would these tire mfgs publish pressure data that is dangerously under inflated? The answer of course is they wouldn't.

You may notice perusing the charts that each specific tire and size has it's own table. Some start as low as 35 PSI, some start at 70-75 PSI. It depends on the tire and load.

Nowhere in any of this do I see something that says use the max sidewall number when your load is less than the max capacity.

I will say this to the OP. You can follow the published guidelines or you can follow the random internet guy opinions. My OPINION is the published guidelines are the way to go.

Wild Friday on the resident tire forum.... jeez people. Tires should be inflated to the proper pressure provided on the door sill. For my truck when I ran 10 ply there were two different numbers for loaded or unloaded. Unloaded e rated tires for the rear called for something in the 40s. I made a choice to run it higher. With the h rated tires I have now I keep em at 100 all around.

I had the same problem when I put new tires on our truck last summer. No matter what pressure I used the truck was all over the road. When I looked at tire reviews on the web it was a fairly common problem with those tires. Luckly Discount Tires let me trade the tires back in for what I had paid for them when I went with the next higher priced tire, no problems with the second set of tires.

Gary

And since some posters are attempting to downplay or ignore the dangers of underinflating tires, here is a NHTSA study showing how a significant number of pre-crash tire failures are directly related to underinflated tires.

http://www-nrd.nhtsa.dot.gov/Pubs/811617.pdf

In addition, this number increases drastically when the under inflated amount is 25% or more.

Under inflated tires = Danger

Considering ALL the other sources and info is subject to the standards, regulations, and compliance regulations of the sources I quoted, it's pretty safe to say the 'other facts' are either incorrect or misinterpreted.

ah64id wrote:
I see max load and max pressure, what about at a load less than max?

Have a link for a lower load? On wait, I already posted that for you.

Yeah tires do have ratings, all you seem to care about is max. I gave you a link to a chart for loads less than max, made by a tire company and similar to many other tire companies charts, and you ignore it.

If this is how you are with tires I'd hate to see you react whe the fuel gage hits 1/2......

I would say it for the last time, but somehow I don't think it will get thru to you.

These are not MY opinions, all the data I am presenting is based on published data from vehicle and tire manufacturers. The only thing you are giving is an opinion, one that doesn't hold any water when presented with the facts.

Heck I even showed you the door jam sticker showing a 40 psi recommended pressure on an OEM LRE tires rated at 80 psi max, what more is there to comprehend? It's not imagination, it's fact pure and simple.

In your, and only your, opinion running a tire at a pressure appropriate for its load is under inflated if that's less than 90% of max. You are the first one I have ever read that statement from. It's NOT under inflated, it's called PROPER INFLATION.

Firestones issue was under inflation, but only because it wasn't enough air for the weight and NOT because it was less than 90% of MAX.

Quote: "The Commercial Vehicle Safety Alliance is currently exploring how to define underinflation for enforcement purposes. CVSA has already settled on a definition of a "flat" tire: 50% of the max cold inflation pressure stamped on the sidewall of the tire, e.g., 60 psi in a tire stamped for its max load at 120 psi inflation pressure."

Source: http://www.truckinginfo.com/channel/drivers/article/story/2013/07/what-exactly-constitutes-an-underinflated-truck-tire.aspx

FMCSA and CVSA and multiple DOT enforcement are pretty credible sources. Granted, passenger vehicles are seldom (ever?) cited for under inflated tires, so we have to look at the professional references.