What is the appropriate pressure for the tires of my SUV?

Question

The doorjam of my Ford Explorer says they should be 26 psi. I've NEVER (even in the winter) had them that low. They appear flat and make noise below 35 psi, but I worry that overshooting could be dangerous. Are gas station air gauges just inaccurate?

By the way the current temps are in the 90s here. The Explorer weighs approx. 4000 lbs.

Answer 1

PUMP UP THE PRESSURE!
Ford put the recommended air pressure way to low as a comfort thing. Find out what the "Maximum" air pressure is on the sidewall of the tire and set the pressure at that. If the ride is too firm, then back off the air pressure little by little from there.
I worked in the wholesale and retail end of the tire & custom wheel industry for 30 years and ALL of us blamed the 26psi for the tire failures and NOT the Firestone/Bridgestone company. What that 26psi does is increases rolling resistance and that makes extra friction which adds extra heat build up. This slowly weakens the belt system and increases the chance of tire seperation. The Firestone Tires that came OEM on most Explorers were very good on longevity and the Explorer sold well-this meant there were millions of these tires on the road which increased the exposure.
We could not understand why Firestone rolled over & gave up- The tire was VERY good-the air pressure sucked and Ford created the problem.

Answer 2

Now that you have 8 wrong answers, let's try one from someone who actually works in the industry and knows what he is talking about. Sorry to be crude but correct tire pressures are a safety issue and I take it very seriously.

A Ford Explorer with a recommended psi of 26 front and rear means probably a late 90's model with a P235/75R15 105S tire on it. Ford used several different tire sizes on this vehicle but only recommended 26 psi when using that size.

At 26 psi a P235/75R15 105S sized tire has a load carrying capacity of 1,753 lb. Multiply that by 4 tires and you have a total load carrying capacity of 7,102 lb. Your Explorer has a Gross Vehicle Weight of 5,280 lb. Thus, even when your vehicle is loaded to the gills you still have almost a 2,000 lb reserve of load carrying capacity in the tires.

In other words, no worries.

So why does Ford recommend 26 psi? Is it just for comfort as was erroneously alluded to above? Absolutely not. Vehicle manufacturers do thousands of miles of testing and work closely with tire manufacturers to determine the best tire sizes to use on vehicles and the best inflation pressures for them. Things considered include not just ride quality but load carrying capacity, wear, braking, and most importantly emergency handling. By using a tire pressure other than what the vehicle manufacturer recommends what you are doing is re-engineering the vehicle. Unless you can say with certainty that you know more about vehicle and tire dynamics than rooms full of Automotive Engineering degrees then it is probably best to stick with what the people who actually designed the vehicle recommend.

They didn't just make the number up.

Inflating the tires beyond what is recommended by the vehicle manufacturer can be dangerous. The tires are more suspectible to damage and premature wear (which could cause blowouts) and might upset how the vehicle handles in emergency situations which could result in a sudden loss of traction when you need it most.

Set the pressure to 26 psi, in the morning when the tires are coolest and have not been driven for any distance yet and always check the pressure at least once a month under the same conditions.

ASE Certified Automotive Service Advisor

Answer 3

Personally I would say I'm a tad unconventional but here's what I've done. Note the maximum pressure on your tire sidewall. Add the door jam super low pressure together and divide by two. That's the inflated pressure I've been using as a guide.

I spoke with a tire engineer at Yokohama in California a year ago. His statement was the maximum pressure listed on the tires is perfectly safe. You may not enjoy riding around with the stamped tire high pressures as it may be a bit too rough. Personally if you keep an eye on your tread wear. I'd shoot for more pressure.

If you ever get the chance to have all your tires deflated / purged and re-inflated with nitrogen @$5.00 per tire do it. Nitrogen is an inert clean gas with molecules hundreds of times larger than air. Nitrogen will not leak of as fast, will not gain pressure as much after a long hard ride and it's been proven tires last conservatively 15 - 20% longer. The real beauty is that your inner tire never will see moisture which attacks both steel and aluminum wheels.

Good luck!

Answer 4

Go with what the vehicle manufacturer says. The number on the door is what comes from Ford. You may want to consult your owner's manual for more detailed information, however. 26 seems low, maybe that's a minimum pressure, so I'd check the owner's manual to be sure.

Gas station gauges can be inaccurate. It's best to carry your own tire pressure gauge, they are very inexpensive (a simple pen-style will be fine) and don't take up much space in the glove box.

Answer 5

I've never seen a suv with tire pressure that low on the door jam.

If you look at the tire there should be a psi rating in parenthesis. My guess the psi should be max 44 psi. With the summer heat I would make it about 40psi

Answer 6

It depends on the load range of tire you have and if you haul heavy loads an a regular basis. If they are passenger car tires then 36 is good with only hauling passengers and not at the maximum GVW weight.

Answer 7

Fill them to what ever the sidewall of the tire says.

Answer 8

look on the side of the tire the directions on air presser and load rating are there.

Answer 9

larkztounge has the best answer, it is what i was going to tell you