Tire pressure and old wives tales.

[two-niner]

I had just seen (on another forum)(which was taken down quickly) an old wives tale about tire inflation.
The gist of the matter was to inflate tires per manufacturers spec's, then add five (5) lbs. Personally I have never done that.
I am looking at Michelins RV Tires 32 page booklet. Nowhere do they say, state or intimate to add five pounds of air above their recommendation.
It's time to put this chestnut to bed, at least for Michelins.
My old computer will freeze if I try to make a clicky but here it is:
www.michelinrvtires.com
Dag nag it, the clicky worked.

Kerry

[TandW]

Sadly, you and then I, have just perpetuated your statement. Good luck!!

[Wayne M]

I never have heard that about extra air.

I inflate to tire manufacturer's recommended pressure and I do it when the tires are cold. (early morning, or late evening)

[TandW]

Come on Wayne!!

[InPursuit]

If you are truly inflating to the "Listed" PSI on the sidewall then in nearly every instance you will be OVER inflating and causing yourself to endure a harsher ride than you have to.

The "Listed" max PSI is based on a max weight.
eg 95PSI for 4500lbs
but if the weight is only 3800lbs... (84%)
then you could go to 84% of 95psi or 79.8lbs

KNOW your weight and calculate.

[TandW]

I can't believe from your formula that some apps would only require 50# in a 95# tire. Did you own a Ford Explorer in '94?

[InPursuit]

Originally Posted by TandW

I can't believe from your formula that some apps would only require 50# in a 95# tire. Did you own a Ford Explorer in '94?

That calculation isn't the be all and end all of the process.
It is the OBJECTIVE starting point.
The wheel rating is the next factor (more for older units).

If you are inclined you can balance that against what your chassis maker recommended 5, 10 or 20 years prior too.

As to your extreme example...
what I suspect happens is that tire salesmen push (and nervous owners accept) 14ply G rated tires when a 12 ply F will serve the need of their weight & load more than adequately. Follow?

And of course some common sense has to be applied too. But just because the side wall says 95 is NOT the reason to actually inflate to 95. 95 may in fact be correct (I'd doubt it) but please do so based on rational and objective data. Clear?

I hope everyone reading this thread KNOW their rig weights and tire ratings and aren't depending on anecdotes and conjecture and old wives tales to base their decisions on.

[TandW]

It's just exactly like I said to the OP. Some old wives tale in perpetuity!!

[mudpuppy]

I wonder how many blowouts are due to under inflated tires by folks looking for a Cadillac ride from a truck chassis.

[TandW]

Mudpuppy, your on track!! I wonder what happened in Charlotte, yesterday.

[InPursuit]

Originally Posted by mudpuppy

I wonder how many blowouts are due to under inflated tires by folks looking for a Cadillac ride from a truck chassis.

I didn't want to go there...
speaking ill of the dead and in light of the other thread on pressures.

But since you have broken that ground then yeah I'd be real interested to know all the data. I suspect the issue(s) won't be tire pressure per se though but rather complacency and bad habits regarding all the maintenance issues.

A worn tie rod and a bad chuck hole is all it takes too.

[TXiceman]

The big thing that has not even been mentioned here is to change to winter air in the cold months and summer air during the hot months. Also have to consider high altitude air when driving in the mountains.

Ken

[mrschwarz]

What is 'winter air'. Does it come from Canada?

[Gotta_P]

Originally Posted by mrschwarz

What is 'winter air'. Does it come from Canada?

No, you just have to ensure the air pump is in the airconditioning so the air is cold!