Tire pressures

[OVERKILL]

Originally Posted By: 4WD
Maybe something to do with Firestone - I ran a GMC during this mess with 6" of lift and drove like a madman on way oversized BFG's ...


Yes, Firestone took some blame in the situation as well.

 

[ltslimjim]

Personally, I usually inflate maybe 2 or 3 psi cold over the recommended pressure. 2 reasons:
1) I don't check the air often enough
2) A couple psi shouldn't cause that much stiffer of a ride and might yield slight MPG gains, as long as treadwear doesn't become focused towards the center it's not too much; IMO. Can depend on tire size and rim changes from OE too, am I right?

 

[OVERKILL]

Originally Posted By: ltslimjim
Personally, I usually inflate maybe 2 or 3 psi cold over the recommended pressure. 2 reasons:
1) I don't check the air often enough
2) A couple psi shouldn't cause that much stiffer of a ride and might yield slight MPG gains, as long as treadwear doesn't become focused towards the center it's not too much; IMO. Can depend on tire size and rim changes from OE too, am I right?


That's one of my mechanic buddy's logic for customer cars. He always over-inflates them by a couple of PSI because in his words "I can tell them until I'm blue in the face but you and I both know the only guy checking it is me when it comes in here". And he's probably right.

 

[Wolf359]

Originally Posted By: OVERKILL
Originally Posted By: mattwithcats
And what pressure did Ford originally specify for the Explorer?

Drum roll, please....

"After the Explorer rolled over in company tests prior to production Ford decided to lower the suspension and remove air from the tires to 26 psi compared to 35 psi for the same tires on the Ranger."


So because of Ford doing something dubious with one vehicle, it negates the validity of the process for the entire industry?

What thoroughly vetted protocol are you offering up as an alternative to what the OEM provides here then? Because your previous post hints at your process basically involving using OEM as a minimum, sidewall as the max and tossing darts to arrive at some intermediate value...

I'm not sure exactly who was really to blame on that. Not sure it was 100% Ford or Firestone. But I believe it was a bad combination of hot weather, over loaded vehicles, long trips, under inflated tires and defective tires. Since then, you have tire pressure monitors and not that many defective tire recalls.

 

[OVERKILL]

Originally Posted By: Wolf359
Originally Posted By: OVERKILL
Originally Posted By: mattwithcats
And what pressure did Ford originally specify for the Explorer?

Drum roll, please....

"After the Explorer rolled over in company tests prior to production Ford decided to lower the suspension and remove air from the tires to 26 psi compared to 35 psi for the same tires on the Ranger."


So because of Ford doing something dubious with one vehicle, it negates the validity of the process for the entire industry?

What thoroughly vetted protocol are you offering up as an alternative to what the OEM provides here then? Because your previous post hints at your process basically involving using OEM as a minimum, sidewall as the max and tossing darts to arrive at some intermediate value...

I'm not sure exactly who was really to blame on that. Not sure it was 100% Ford or Firestone. But I believe it was a bad combination of hot weather, over loaded vehicles, long trips, under inflated tires and defective tires. Since then, you have tire pressure monitors and not that many defective tire recalls.

 

[chrisri]

It's unbelievable that adult people with driving license will use max allowable press of a tyre as a rule over vehicle manufactures recommendations. Cars aren't garden trolleys.

 

[CapriRacer]

Like Kuato, I always enjoy these threads.

Some things to think about.

* Tire manufacturers point to the vehicle tire placard as the proper pressure.

* Alternate pressures rarely appear on US designed cars - Mostly European and especially German cars.

* One of the reasons NHTSA calls for a single tire inflation pressure on the vehicle tire placard is the confusion factor - as witnessed by this thread.

* Tires are standardized and the load tables do not vary by tire manufacturer. That means the pressure specified on the vehicle tire placard is applicable regardless of who manufacturers the tire. Any differences between tires that might be perceived by the driver is a function of the design of the parts of the tire that affect ride and handling and not its load carrying capacity.

* Car manufacturers do extensive testing at the placard pressures and not so much at other tire pressures.

* Even at the pressure specified for the Ford Explorer, the tires were rated to carry the GAWR (Gross Axle Weight Rating) NHTSA did not find fault with the GAWR's.

* There were some specific defects in the Firestone tires that do not appear in other tires. Everyone seems to forget that other tires appeared on the Ford Explorer and those didn't fail.

*

 

[Eddie]

I have always found that the drivers door pressure recommendation results in even tire wear. I also set tires pressures overnight cold with a digital gauge at +1 psig. Ed

 

[mightymousetech]

Originally Posted By: Quattro Pete
Yeah, what I'm seeing in the US is that the vehicle placard shows only the full load PSI, but not half load.

I guess car manufacturers assume that most of us are too lazy and will not adjust our tire pressures as we change loads, so they just tell us to stay at full load pressures at all times.

My old 530i actually shows both full and half load values, but that's an exception...



My BMW shows pressures for loaded and unloaded and above and below 160 km/hr driving.

But tires also make a difference. I no longer run runcrap tires, which are also a fair bit wider than stock. Stock pressures are 33/36, but I have found 35/35 to be best for my current set up.

 

[Wolf359]

Originally Posted By: chrisri
It's unbelievable that adult people with driving license will use max allowable press of a tyre as a rule over vehicle manufactures recommendations. Cars aren't garden trolleys.


At least they do that. I had a cousin once who had just gotten their license recently show me the car he bought and he was proud that he had it at 80! He thought the stock pressure made the tire look under inflated when that's what they're supposed to look like. I don't think the tire was even rated for 40. Had to tell him to lower it down to 35 which is what the car sticker said. I can just imagine the ride, I can tell the difference in a slightly harsher ride at 36 vs 32. Can't imagine what it would have been like at 80.