32 PSI for BFG 265/70R17, L.R. C, Light Truck tires?

[PJA]

I have heard that ON-road tire pressure should be determined by the weight of the vehicle, and NOT the “Maximum” pressure on the side of the tire.

The sticker on the FJ door says 32 PSI for the stock 265/70R17 “PASSENGER” tires.

Sooo---- Can I/Should I run 32 PSI or a little above in my BFG A/T KO Tires: LT 265/70R17, Load Range C, on the freeway?

Any thoughts appreciated re this---

Thanks-

[fivestar13]

I'd say you'd feel happier around 35 psi on the road for the given tire.

That's what I ran when I had KOs on my Jeeps (CJs) and old Pathfinder ('88)

[FJ Cruiser 1]

I run 36psi in my BFG all terrain KO tires on the road

[caddo]

I have the same tires...

America's Tire put mine at 40 psi and lower them to 35psi when I asked them about tire pressure. They told me because these are truck tires their computer says they should be at 40psi.. They asked me how often I go offroading, I said maybe once a month.. the guy then said he'd put mine at 35psi.. but I shouldnt run them too low.

at 35psi they looked a bit deflated, I parked the truck on gravel when at home, drove around for a day then bumped all 4 up to 38psi, drove around for another 2-3 days, did a long roadtrip (from San Jose to Death Valley) and went offroading for 4 days. no issues (that I know of anyway).

I'm still running at 38psi right now.

[mikesfj]

I contacted BFG regarding this, and they said only to run the pressure recommended by the manufacturer (32 PSi in our case) for the stock size. The only time pressure should deveiate from this is when you are running a size other than stock. Trying to guess at what pressure is good based on what was good on a different vehicle will result in uneven tire wear and poor handling/ride. I run BFG load E on my FJ and run only 32 psi. The ride is good and tire wear so far seems even. I have heard others complain about the ride with a load E tire but you find that they are running very high pressures. The load E in my experience protects my tires from sidewall tears and tread blowouts from sharp rocks (Very common problem here in northern Utah).

[PJA]

Thanks to all for the responses. Very helpful to me, and exactly what I was looking for.

PJA

[Landrover]

Run them at or near max. You are inflating the "tire", not the vehicle. Read this article:

Consumer Reports Article - MSN Autos

The Problem of Underinflation
Surveys have shown that as many as half the cars on the road may be riding on one or more underinflated tires. Part of the problem is that tires lose air through the rubber and at interfaces with the wheel and valve, sometimes so slowly that many people don't realize it has happened. Seasonal temperature changes may also cause the tire pressure to drop.
Because the sidewall flexes more at lower tire pressures, underinflation compromises the driving control that a tire is designed to provide. Even a small pressure loss—such as 4 psi—can affect a car's handling, making it harder to control. It can also make the ride softer and the car wallow. In addition, underinflated tires lower a vehicle's fuel economy, which can cost you more money at the pump.

A sidewall that flexes too much can also cause heat to build up excessively, which can shorten a tire's life and possibly lead to a tread separation or blowout. Using a computer simulation program, the Crash Safety Research Center at Penn State's Pennsylvania Transportation Institute has shed more light on how a tire performs with lower air pressure. Every tire has a speed at which a deformation called a "standing wave" occurs along its circumference, causing a rise in temperature and eventual failure. The research center has found that when the tire pressure is lowered, the energy used by the tire is increased significantly. The result is a rapid rise in temperature, rolling resistance, and tire fatigue.

[PJA]

Hi Landrover-

Thanks very much for the input.

Actually, reading on down the C.R. article, it says:

"Tire-Inflation Maintenance Tips
*
*
* Set the tires to the automaker's recommended tire pressure. This is printed on a placard in the car, either on a doorjamb, the fuel-filler door, or on the inside of the glove-compartment lid. Don't go by the "maximum inflation pressure" imprinted on the tire.”

In the FJ case, this would in fact be 32 PSI?

BTW- I saw an article that said NOT to run your tires at the MAX pressure (unless your vehicle & cargo actually weighed the “MAX” load for for those tires). The target is to have a tread that does not bulge in the center, nor ride on the outside of the treads.
A way to test for this before a bad wear pattern is visible is to take a piece of chalk and draw a straight line across each tire, from side to side. Then drive 200-300 ft (or what ever it takes) and see if the chalk is warn off evenly across the tire (good), or mainly in the center (bad), or mainly on the outside, sparing the center tread (bad).

I though that was a pretty clever idea---

Thanks again for the response-

[Landrover]

PJA previously said:

Hi Landrover-

Thanks very much for the input.

Actually, reading on down the C.R. article, it says:

"Tire-Inflation Maintenance Tips
*
*
* Set the tires to the automaker's recommended tire pressure. This is printed on a placard in the car, either on a doorjamb, the fuel-filler door, or on the inside of the glove-compartment lid. Don't go by the "maximum inflation pressure" imprinted on the tire.”

In the FJ case, this would in fact be 32 PSI?

BTW- I saw an article that said NOT to run your tires at the MAX pressure (unless your vehicle & cargo actually weighed the “MAX” load for for those tires). The target is to have a tread that does not bulge in the center, nor ride on the outside of the treads.
A way to test for this before a bad wear pattern is visible is to take a piece of chalk and draw a straight line across each tire, from side to side. Then drive 200-300 ft (or what ever it takes) and see if the chalk is warn off evenly across the tire (good), or mainly in the center (bad), or mainly on the outside, sparing the center tread (bad).

I though that was a pretty clever idea---

Thanks again for the response-

I think this is strictly a liability issue. If the tire manufacturer tells you to run their tire at max, and max being more than the vehicle manufacturer tells you to run, and then you roll your FJ, someone is going to say you ran your tires higher than recomended and that is why it rolled. That's the same reason that when you get your tires changed, the tire shop will always install them at vehicle rated inflation.

So I guess it's your choice. One of the points of the article that I posted says to run at what the vehicle manufacturer says to run at, but I don't think that takes into consideration that you are putting a higher load range tire on said vehicle, but assumes you are using stock tires. I think the more important point of that article is the dangers (well I don't know about dangers, but we all remember that Firestone/Ford Explorer fiasco) of an underinflated tire.

I can tell you right now that running your tires that low, that you will not get as much mileage or longevity out of them. I can't/dont' want to tell you what to do, but I run my tires at max whatever they may be, passenger, C, D, or bleh....E. O.K., o.k., when I had some load range E Goodyear MT/R's on my Discovery I didn't run them at 80psi, it was just too rough. I did run them about 60psi however and got almost 50,000 miles out of them. I usually like the firmer ride that a higher load range tire give me on the road especially on softer sprung trucks such as ours.

Good idea on the chalk btw. I think that you'll find that 32psi will leave the outside of the tire rubbing more than the inside. Let me know what you find out.

[PJA]

Landrover-

"I think this is strictly a liability issue."

I would certainly agree that there are significant liability issues here

"One of the points of the article that I posted says to run at what the vehicle manufacturer says to run at, but I don't think that takes into consideration that you are putting a higher load range tire on said vehicle, but assumes you are using stock tires."

A good point...

"I think the more important point of that article is the dangers (well I don't know about dangers, but we all remember that Firestone/Ford Explorer fiasco) of an under inflated tire."

Actually, this is my main concern (more than gas mileage and longevity).

"Good idea on the chalk btw. I think that you'll find that 32psi will leave the outside of the tire rubbing more than the inside. Let me know what you find out."

Won’t be able to try it for several days, but I’ll let you know when I do-