"LT" tire pressures on Expedition

[Rustycamperpant]

I moved up from "Heavy Load" tires on my Expedition to real "LT" tires. Max air pressure on the new tires is 80#, max pressure on the heavy load tires was 50#. I always ran my other tires at max pressure when towing my TT.

I talked to the tire installer and asked him what they set the pressure at and he responded, "To whatever is specified on the door sticker". This will be in the 36 - 38# range.

What do you all do? I was thinking all along I should run much higher pressure on the LTs just like I did on the heavy load tires. Thanks in advance...

[Cummins12V98]

Use weight/inflation chart for your tires, add 5psi to rear and 10 psi to front. Go to local scales and get your axle weights and divide by 2. Simple!!!

[ghostrider421]

BenK wrote:
Also, the Ford Explorer rollover begot lots of these labels and tire PSI monitoring...managed to the idiot and gorilla...

I had one of those Explorers. Everytime it was in for service, the tech would lower the tire pressure to 33psi - despite tire sidewall was 44psi! Of course the tires heated up and had several blowouts before it flipped on my husband one day on I25. Not a pretty sight. The unnecessary trauma and weeks of rehab and exercise at our expense when it was the dealers fault. Eventually we were repaid - but it took years.

[Rustycamperpant]

To double check the installers figures you have to use the load capacity the OE tires provided at vehicle manufacturer recommended inflation pressures. Then find the chart for the replacement tires and compare the load capacity they are providing at the installers recommended inflation pressures. Industry standards require a minimum load capacity equal to what the OE tires were providing.

This is excactly what I did to come up with the 50-55# psi number. Interesting how such a seemingly simple question takes so many turns. Makes for interesting reading. I do BTW have the official Inflation chart for cross referencing the tires ... and they are still OE size.

Also, I am not "long gone" I pretty much only read this forum while I am at work. Dont tell my boss.....

[JIMNLIN]

OP wrote:
Thanks for all of your input though, Im feeling pretty good about my choice..

OP last post was 4-6 and made his choice ... days and pages later were hearing about blah blah blah and blab or is it blabbering.... or chest pounding.... or what was the topic anyhow. Where's the dead horse pic. The OP is long gone.

[BenK]

Mostly a CYA mandated by corporate legal/risk management

Courts know that most will NOT read the manual, Read Me First, warning labels, etc, etc...but that sets the min for any court case...what else can any OEM do?

Also, the Ford Explorer rollover begot lots of these labels and tire PSI monitoring...managed to the idiot and gorilla....that was one key advice from my mentors while still in college & first engineering jobs (part working way through college...tire monkey/welder/designer/draftsman/etc)

Part of the why some things have lots and lots of ‘safety margin’. A bridge will have X times...while an airplane can only afford 0.X times...

Then the wacko court awards...why we left the people movers industry. We had over 70% of the variable speed controlled ski lifts in the USA, but the juries were awarding huge sums based on ‘todays’ standards...even though that ski lift was designed, installed, certified, etc....decades ago...

[Grit_dog]

The bad part is people who are either blissfully ignorant or simply obtuse arguing about things they (should) know that they know or have their eyes and ears open to learning about it.
I don’t comment on things I’m not well read in but I sure read and glean good info from others

[Grit_dog]

So based on the discussion this far, there is a reason for yellow door stickers, min tire psi etc. and it’s fine. It cannot be expected that more than a certain % of the population want or can analyze things or even recognize hazards.
Hence the no bath tub sticker on your wife’s hair dryer and the no fingers sticker on your lawnmower.
The point is, if one knows wtf they are doing, they can get more out of their machines and their life.

[Grit_dog]

You’re spot on Ralph! Lol at the flubber tire.
If it makes you feel better there are still some PEs with common sense.

We re-engineered a design build project last year, replacing the prescribed 2 - bridges and temporary detour with one precast concrete arch structure and no detour construction. Saved about $4M. Without all 3 parties having common sense, owner, designer, contractor, it would have never happened and often doesn’t.
When I have a good designer that listens, we tend to make money. When I have a bookworm designer, we tend to burn money like it’s free!

[Ralph_Cramden]

.

[CALandLIN]

Rustycamperpants wrote:
I moved up from "Heavy Load" tires on my Expedition to real "LT" tires. Max air pressure on the new tires is 80#, max pressure on the heavy load tires was 50#. I always ran my other tires at max pressure when towing my TT.

I talked to the tire installer and asked him what they set the pressure at and he responded, "To whatever is specified on the door sticker". This will be in the 36 - 38# range.

What do you all do? I was thinking all along I should run much higher pressure on the LTs just like I did on the heavy load tires. Thanks in advance...

To double check the installers figures you have to use the load capacity the OE tires provided at vehicle manufacturer recommended inflation pressures. Then find the chart for the replacement tires and compare the load capacity they are providing at the installers recommended inflation pressures. Industry standards require a minimum load capacity equal to what the OE tires were providing.

[Grit_dog]

Ralph Cramden wrote:

Grit dog wrote:
I can say heartily that "engineering" is an ever changing blend of the theoretical solution, the practical solution, the politics, the cost, the liability involved with the particular solution and the human opinion or error aspect.

That's a good one.


BTW, did anyone mention nitrogen in this thread? Now off to pump up my tire and see if I can blow the valve stem out of it.

Don't say the N word unless you want 10 pages out of this thread.
BTW I got $20 for anyone who will bite, that you don't blow a valve stem out! Lol

[ghostrider421]

Only time I worry about rim pressure, is when they are those funky 16.5 split rims.

[BenK]

You are re-engineering part of the suspension by changing tire class and size

The door label info is for the tire class and size listed on that label. If changing (re-engineering) the tire class and size, you need to know and understand a bit more

Tires do much more than just carry weight. That ‘squishiness’ mentioned is, IMHO, more to do with how the vehicle engineers designed in ‘ride quality’...not towing metrics

Ask what the ‘new’ tires OEM specifications for wheel rim width range is...vs...what your actual rim width is. Make sure you have the ‘bead to bead’ width, as that is what most OEM tire specifications use

Narrower is more for ‘ride quality’ and the wider is more for ‘handling’ performance. All of my after market wheel rim width is at or a bit wider than tire spec and is the way I like it....ride quality is not on my ‘have to have list’ and is at the bottom of my ‘Nice to have list’

Barry is one of the tire engineers on this forum...listen to him. Some of the other advice is border line dangerous, but the advice on these freebie forums are worth the price paid...

[dodge_guy]

“E” rayed tires are too much for a 1/2 ton. They are unecesaary and heavy. Most it would need are “C” rated tires. Running tires severely under inflated is not good for longevity or handling.