How much air pressure?

[Flandry]

...Most people don't realize tires are as important to the ride as shocks and the suspension..

Proper inflation also impacts fuel economy. My personal measurements show tires that are low by 3-4 pounds can cost a first-gen Explorer around 1 mile per gallon.

 

[ktnj]

I run 30 psi on my Michelin LTX M/S tires (max rating is 35 psi). This is my second set. I got 101,000 problem-free miles out of my first set.

Wow, that's incredible. I am replacing some tires on my other car because the outer edges wore faster than the middle. I tried to compensate with higher inflation pressure but I wish I had thought of this 'chalk test' idea back when they were newer... probably would have helped, even though I regularly check the inflation pressure. Obviously the tire pressure recommended on the door jam is not going to guarantee long life on all types and brands of tires.

 

[Tbars4]

..The psi on your door jamb, and in your owners manual are for the original tires your vehicle came with new, not any aftermarket tires...

 

[Tbars4]

Proper inflation also impacts fuel economy. My personal measurements show tires that are low by 3-4 pounds can cost a first-gen Explorer around 1 mile per gallon.

Quote:
Originally Posted by tbars4
...Most people don't realize tires are as important to the ride as shocks and the suspension..


...My comment was to the ride of the vehicle but yes, proper inflation is important for tire wear and fuel economy ...along with these items...
http://www.explorerforum.com/forums/showpost.php?p=1947463&postcount=6

 

[90ranajo]

It looks like you are going from a SL tire with a Load Index of 105 to a plus sized XL tire with a Load Index of 109. You should keep to the OE inflation pressure.

 

[Flandry]

Wow, that's incredible. I am replacing some tires on my other car because the outer edges wore faster than the middle. I tried to compensate with higher inflation pressure but I wish I had thought of this 'chalk test' idea back when they were newer... probably would have helped, even though I regularly check the inflation pressure. Obviously the tire pressure recommended on the door jam is not going to guarantee long life on all types and brands of tires.

This is actually not quite so incredible as it might seem. If you check out reviews on Tirerack.com, you'll find a number of people have gotten over 100K miles from their Michelin LTX M/S tires. But proper inflation and alignment are the key. I check the pressure regularly. I also do a four-wheel alignment when I put new tires on and another at 40-50K miles. Incidentally, many folks consider these Michelin's to be the quietest tires you can put on an Explorer and I agree. They are also considered to be the best tires to reduce the shakes some first-gens suffer from at certain speeds.

As for your tire wear, that definitely can be caused from under-inflation. But it can also be caused by bent steering or idler arms causing incorrect toe-in. So I'd definitely get an alignment when you change out the tires.

 

[Smaug]

The tire inflation info on the truck door say 30 psi for fronts and 35 psi for the rears. For my front wheel drive sedan the tire pressures I use are 32 psi for fronts and 30 psi for the rears, though the OEM specs call for 30 psi all 'round. Reason? The front end is way heavier than the rear.

The OEM spec ratio of 30 psi Fr to 35 psi Rr makes sense for a 2x4 (or is it 4x2) Pickup truck that sees real work load, it doesn't seem to make much sense for an enclosed Explorer 4x4 whose rear tires that are not going to carry loads that exceed the normal weight of the truck's front end. I not likely to load anything in the back that is as heavy as the truck's engine. The engine & trans being the main weight difference between the Fr and Rr axle weight.

So it would seem to me that unless the gross rear-end load is going to exceed the gross weight of the front-end, the tire pressure should either 1) be the same Fr & Rr or 2) the tire pressure in the front should actually be higher than the rear since the gross weight of front-end is heavier in a vehicle only carrying passengers. (I'm in favor of choice #2)

AM I RIGHT ABOUT THIS????

Presently I'm using 32 psi all around on a set of P235/75x15s (Pepboys tire installer's decision. He's got a '95/w plow and the same tires I bought). Though I'm inclined to use the same philosophy as my Front Wheel Drive car.... Higher Fr lower Rr psi.

 

[SCB2525]

I've heard multiple places that LTX M/S tires are best for ride, but has anyone detemined if one certain set of tires is getting them better gas mileage? In my case, I could care less about the ride if it meant a lower cost of operation be it from reduced suspension/tire wear and better gas mileage.

 

[Masterd]

I do 32psi all around as well...

I tried 40 psi once, since my tires will do 45, and it rode like it had concrete wheels.

 

[jd4242]

my old 33x12.5 bf mud that i have on the truck now dont give a max psi they just say max load at 35 psi.so what should they be filled too?i have them at 32 now but they feel very soft/bouncy.also im pretty sure my new 35x12.5 bf mud dont say either,they are in storage now but what should they be run at?

 

[Deleted member 128963]

Ford Recommended Pressure

I noticed that I have not seen here, any mention of the recommended tire pressure as stated by Ford on the door sticker. I have always just kept mine at 32 or 34 psi and never really gave it any thought until I started reading these posts. My Stock '94 Explorer Limited has Goodyear Wrangler RT/S P235-75R15 which state a max pressure of 44 psi but the Ford recommendation for that same size is 26 psi cold. Now, that, to me, seems to be quite a big range. I'm going to try the 26 and work my way up to the "max-10%" while using the chalk test over the next few days to see how the ride and handling characteristics change. I'll let you know should I have an epiphany.

 

[Maniak]

First thing. Unless you are running the actual tire that came on the explorer and have had the sticker on the door jamb replaced during the recall just ignore the sticker for tire inflation info.

What you should do is buy new tires and fill them up for a test. 32 psi for tires with a max of 35 and maybe 40 for 44 psi tire. Now draw a line across the tread with chalk. Drive in a straight line and then look at the line on the tire. If the center wears firs take some air out. If the edge wears first put some more air in.

It is possible to get the line to wear cleany and still be wrong. This will happen if you use a higher load rated tire or too narrow or wide of a rim for the tire.
~Mark

 

[Deleted member 128963]

Thanks for the info

I'll have to check out that recall re: the door jamb sticker. I think all service bulletins and calls for service were done but I'm not sure.

Thanks for the info.
Bill

 

[johnvosh]

Sorry to revive an old thread but I just wanted to say that my '93 explorer does have the revised sticker for the air pressure.

The stock air pressure for the specified Firestone tires was 26PSI for both front and back, then the new label says 30PSI for both front and back.

To me this is too low of a pressure for something that weighs so much so I try to keep the tires at around 35PSI.

 

[Smaug]

Yeah, the best way is still the chalk method. I do all 4 tires when they're new in large parking lot and every year or 10,000 miles which ever comes first. If you drive it every day all year long this method seems to treat the tires well. If it's not your main vehicle or you use it only in the winter or just for sport, just pick a milage and stick to it. But from what I've read over the last 5 years 85% of tire-max psi seems to be the most common # people end up with.