my new super crew arrived with 45 lbs of air pressure in all tires, my drivers door sticker says 30 in the front and 35 in the rear, i have 17 inch stock goodyears on the crew, does anyone have a suggestion on proper air pressure?

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2001 Super Crew 4x4,Amazon Green Lariat,Tan Leather, 5.4 liter,Keyless Entry,Towing Package,Captain Chairs,6 CD Changer,Running Boards,Duraliner,Limited Slip,3.55 axle,Skids,and Slider

 

Just from what I have done in the past, I always run my tires at the pressure listed on the tires, not what the vehicle manufacturer says...they aren't the ones making the tires...I have also heard that the vehicles come with a pressure rating for the "most comfortable ride," which to me in a truck, I want it to ride like a truck, not a passenger car....Just my two cents.

 

The pressure in your tires was probably set during the PDI process and is most likely incorrect. Tire inflation ratings from the manufacturer are usually set for best ride, handling and occasional load conditions. They are a good guide for inflation. If you are not hauling heavy items there would be no need to inflate you tires to the sidewall markings, they are in some cases the maximum inflation rate. I usually run my tires to 35 lb. And have never had a problem. The tires have always worn even.

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1999 F150 S.Cab 4x4
Northland Edition,5.4
Off road pkg. Fleetside
Black w/grey int.

 

Also in the supercrew forum:
Nick G;
I've been doing the same drill today ... after reading Brock Yates' article in the Wall Street Journal on the Firestone tire/ Ford Explorer debacle. I have OEM Goodyear Wrangler RT/S P265/70R17's. Dealer had them inflated to 41psi front and 45 psi rear. That's in the driveway, "cold" on a 100 degree (God bless Memphis!!!)day. Assuming a "normal" day is 70 degrees and that inflation pressures rise at approx 2 psi for every 10 degrees above the 70 degree norm then they would have been set at approx 35psi front (41 minus 6) and 39 psi rear(45 minus 6) in a 70 degree garage. The sticker on the driver's side door well sez inflate to 30 psi front and 35 psi rear. What's really interesting is that the side of the tire shows a 35psi max pressure (for max load). That really seemed low to me. I checked the Goodyear home page, but it was useless... no recommended tire pressures. Then checked BF Goodrich's home page -- it's much better -- lot's of detail. Their equivalent tire is also listed as a max (cold) pressure of 35 psi. Sooooo ... after all this rambling, I've reset my pressures to 32psi front and 35 psi rear (compensating for the Memphis heat. Given my previous experience that seems low. Anyone have any suggestions ... wonder what Elvis would have done ?


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2001 F-150 Super Crew Lariat 4x4. 5.4 engine. Chestnut w/ gold trim. Ford/ Duraliner bed insert. Six disc cd changer. Moon roof. 98/99 Expy center console. Bed extender.




[This message has been edited by FedExPilot (edited 08-16-2000).]

 

I found that my truck runs best at 29 all the way around.
The tires seem to "hop" less around sharp corners.

 

thanks guys,,, keep the info flowing, this iste is great ... you guys are a wonderful source of information. i appreaciate yopur help...i like fed ex experiance 90/95 degree florida heat.. i will slowly begin (tonite)deflating the tire presure to coincide with you guys input.

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2001 Super Crew 4x4,Amazon Green Lariat,Tan Leather, 5.4 liter,Keyless Entry,Towing Package,Captain Chairs,6 CD Changer,Running Boards,Duraliner,Limited Slip,3.55 axle,Skids,and Slider

 

Why the different inflation pressures per end of the truck?

Does the higher air pressure in the rear compensate for a load in the bed (or from a trailer)? What about when unloaded. You get more rolling resistance in the front.

Well, how about the weight of the cab(persons in it), a front axle, front driveshaft, transfer case, and engine? If my theory above is a good one, wouldn't you want the higher air pressure to be in the front set of tires?

I understand you read it on the sticker on the truck itself, that's why I'm kind of scared to ask questions. My tires have very rigid sidewalls. Their stability is kept all the way down to 9 psi. But I still keep 35 psi (at least) in each tire (all 4). And ride is still cushy. Sidewalls read 40 psi max. They are radials.

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1999 Red F150 4x4 5.4L XLT X-Cab
Towing Pkg, Corporate 9.75 Rear Axle, 3.55 LS, Corporate 8.8 Front Axle, 3.55 Open, K&N Generation II, JET Chip 32x11.50 Super Swamper SSR
-coming soon
JBA Headers, 40-Series Flomaster exhaust

 

DOES ADJUSTING THE TIRE PRESSURE HAVE AN EFFECT ON THE BALANCE AND POTENTIAL ALINGMENT OF THE TIRES. OR WILL IT SIMPLY EFFECT RIDE AND WEAR.

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2001 Super Crew 4x4,Amazon Green Lariat,Tan Leather, 5.4 liter,Keyless Entry,Towing Package,Captain Chairs,6 CD Changer,Running Boards,Duraliner,Limited Slip,3.55 axle,Skids,and Slider

 

More air equals stiffer ride, turning corners easier, and better gas mileage. However, if over-inflated, tread will wear badly in the center. And you add a little more shock to the rest of the suspension if you hit, like, a pothole or speedbump.

Less air equals cushier ride, more grip on the road, and you take away some of the shock to the suspension. But it's harder to turn the wheels which puts a strain on your steering pump and components. You are also creating more rolling resistance (worse gas mileage). If underinflated, tread will wear badly on the outside edges.

 

My dealer seems to inflate them to a different psi every time I take my truck in. Sometimes 35 all the way round, sometimes 45 all the way round, sometimes 40 the way round, sometimes 40 front 45 rear . . . I don't have a clue. I think my side panel says either 32 or 35 but I like the way they feel at around low to mid 40's all the way round. It handles well and is a little firmer of a ride, which I like.

Tire wear seems normal and quite uniform.

p.s. I have Wrangler LT 245/75R16's on a 97 4x4 Supercab.

 

Dont go by the sticker on the door, that psi is only for a maximum load.

Ill bet I answer this same post once a week. This time, I'll just cut-and-paste my response below:

The actual tire pressure is dependent upon the the weight that is on the tire. The tire's tread should be perfectly flat (width wise), with about an inch of contact (fore to aft). The pressure will will vary with a different type, sizes, construction, and/or load range of the tire.

Any easy way to determine the correct pressure is to air all the way up (to the tire's maximum load range), roll through a little puddle, and look at your footprint. The pattern should not be full width (unless your vehicle normally weighs in at the tire's max load range). This pattern is high-centered - a bow is formed across the width. You may see the entire pattern, but the center will look 'denser' than the edges. Keep airing down, little by little, while checking your pattern and stop when you have a perfectly flat width print of equal density. This is your correct pressure for your current weight. If you air down beyond this point, you will increase the fore-aft contact patch, thus increasing your rolling resistance which will lower your mpg, increase your chance for hydroplaning, increase noise, retard handling, etc.

As you can determine, with an empty bed, the rear pressure should be less than the front pressure. With a loaded bed, the rear pressure will be greater.

 

thanks riotrob,, i read your post on the archives... i was trying to determine if there was an easier way to find the optimum empty load tire pressure without using the puddle trick,,,seems to be a popular topic which tells me it is a ""moving target""" keep trucking,,,

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2001 Super Crew 4x4,Amazon Green Lariat,Tan Leather, 5.4 liter,Keyless Entry,Towing Package,Captain Chairs,6 CD Changer,Running Boards,Duraliner,Limited Slip,3.55 axle,Skids,and Slider