Community Forums

Tireman9 · 03-03-2016, 07:53 PM

Quote:

Originally Posted by slowdown

I seem to have different outlook on tires, so here goes
I think rvs seem to put to small of tire on a lot mhs and then you have to run a lot of air to hold it up witch makes for a firm ride, my tire man tells me to go by air chart on door of my car and that calls for underinflating tires, I also think a hard tire blows out before a tire that gives blow out so with that said I am buying new tires, because mine are 8 years old, and I am going with tire air chart from company on weight and air , I also going to put ruler on side of camper and check height from ground to top of wheel well at full air and chart air if it gives a tinny bit that is where I will run them. Just may have to go lower, no give no heat, weight is always known so not worried.

If the inflation on the tire placard results in lower load capacity that the GAWR the car company is breaking the law and should be reported to NHTSA.

RE ride height. Hope your "ruler" can be read at lest in 0.01" with 0.001" being better and what is used in the tire industry when doing measurements. If you expect reasonably accurate tire deflection rate results.

Tireman9 · 03-03-2016, 07:54 PM

Quote:

Originally Posted by 38Chevy454

Tires run cooler when they have more inflation. Tire heat is from the tire flexing as it rolls and distorts under the load. Running higher air pressure reduces the flex, at slight sacrifice to ride quality. You should run tire pressure at or above the mfr recommended value for your load on the tire, never under that pressure.

As a tire design engineer w/40 years experience
X2

Tireman9 · 03-03-2016, 07:59 PM

Quote:

Originally Posted by Stickdog

Run the tires at the recommended pressure. I run mine at the max 110 psi, if you think that max pressure is too harsh a ride then you need to upgrade your suspension. or lower your load.
If your interested in what can happen with underinflated tires check google for "Ford Explorer under inflated tires".

1. Using your measured load on the heavier end of each axle and the Load/Inflation to learn the MINIMUM inflation you should run

2. As long as you don't exceed tire or wheel max inflation I suggest you rou MINIMUM inflation + 10%

Mr_D · 03-03-2016, 08:02 PM

I run the minimum pressure for my weight plus 5 psi since I have a TPMS built in.

Tireman9 · 03-03-2016, 08:03 PM

Quote:

Originally Posted by slowdown

All have good reasoning, I also run a town car witch has 200,000 miles on it at 32 lbs air from chart not side of tire or 43 lbs and it does not always have 2 people in it. I believe a tire with to much air is not flat on bottom that's not real good. These tires for rv are 75 mph tires and I drive 62, best mileage.

I still think a hard tire blows out first.

"Blowout" is correctly called "Run Low Sidewall Flex Failure". In the tens of tires that have either failed or reached the end of life almost all "blowouts" had physical evidence that proves the tire was run under-inflated.

Tireman9 · 03-03-2016, 08:08 PM

Quote:

Originally Posted by Ray,IN

Both Michelin and Goodyear, even though they publish weight/inflation carts, say to never run less than the vehicle manufacturers recommendation as stated on the tire placard. The Rubber Manufacturers Association states this same thing in CH 4, which pertains to RV tires, pg, 51.
Excerpt: "
However, never use inflation pressure lower than
specified by the vehicle tire placard, certification
label or owner’s manual. Nor should inflation
pressure exceed the maximum pressure molded on
the tire sidewall"

I choose to follow that admonition, others will do as they see fit.

Gee Ray. Why would you ever believe the "idiot" engineers in the tire industry when we all know and have been told that the people that know everything are the mechanics.

(I now end the sarcasm portion of this post)

slowdown · 03-04-2016, 07:46 AM

I believe if mfgers. put themselves at risk they would not put placards for air on doors and it never says to lower weight. We just stack it on and don't weight. Cars included just fill the trunk and back seat and take off. I think placard weights are about 10 percent under max on side of tire, my tires are never loaded for most part so I feel safe with less air. Another ideal I have is what side of rvs and trucks do you see most blowouts, is there a log for that? I seem to believe its the right side because the right side can't seem to get around objects on the road and gets punished and bruised which causes sidewall failures. Before I run max air I will put on a big tire for the load. Good reading posts

Slowdown and have fun.

Ps I just found out my tires have a speed limit on them.

schrederman · 03-07-2016, 10:33 AM

Quote:

Originally Posted by slowdown

I still think a hard tire blows out first.

Sorry but that thought goes against all the engineering and science that went into designing your tires. An over-inflated tire IS a dangerous thing. However, heat buildup from an under-inflated tire causes blow-outs. Running a tire at max cold pressure on the sidewall is NOT over-inflating the tire... and it will be "flat" in it's contact area with the road. That tire will run cooler and carry the weight better than an under-inflated tire... which will be prone to rapid heat build up and... pop goes the weasel...