I am sitting here drinking a cup of coffee and was thinking about tires and what tire pressure you guys and gals are running. I have 225 70r15 on the front and 235r70 on the rear. I had been running about 30 pounds of air in the front and rear tires. I still have the original front end and steering.

I was talking to a guy at a cruise this summer. He had the same set-up that i have. I asked him how it handled . He said it depended on air pressure in his front tires, above 30 pounds truck is all over the place although he said his front needs rebuilt. Mine is in pretty good condition. I dropped the air pressure down to 26 pounds and it made all the differance on how the truck handled. The only down side is trying to turn in tight quarters.

We went on a long ride yesterday about 225 miles and had no trouble.

 

tlb....I always run the maximum as stated on the sidewall. But, my effie has IFS and shocks designed for radial tires. I wonder if we had radial tires and good roads back then, if Henry would have used something different for a front suspension.
_______________________
XFM....
'53 F100

 

You would be surprised how much affect tire air pressure has on riding and handling characteristics. My Jeep Wrangler is supposed to carry 35 pounds of air pressure but it rides like a buckboard with that much pressure in the tires. I usually run about 28 in them instead. I had a 29 Ford rod some years ago and ran about 28 in the front and about 22 in the rear to make it ride and handle comfortably. I realize that running less air pressure can cause premature wear but comfort is important to me also. If you have a stiffly sprung vehicle less air pressure can soften the ride considerably. Also, since pickups have so little weight on the rear it would not be unreasonable to run less air in the rear than in the front provided you are not hauling anything.

Vern

 

I run the max as stated on the tire as well on ALL my vehicles. I'm always looking at fuel mileage.

Kevin Bigwin

 

Steel Belted Radial Tires are designed with a flexable sidewall, the tread always lays flat on the road because of the steel belt. When I worked in the tire trade and Radials were just coming on the market we were always told the pressure needs to be lower that that of bias ply tires. Normally they ran around 24psi, yes they look like they are half flat, but that was is how they are supposed to look. By running higher air pressure the radial can't work as it was designed because the sidewall flex isn't there. Some people will probably read this and think I'm full of bull, but that is just what I was taught on how the Michlen line was designed.

Hope this helps
Rod

 

Im running 31 10.50 15 and on the road I keep them at 50 psi.. but when I go off road I drop them as low as 5psi .. It works well that way.. .. So here what I set them for depanding on condations.. Road/hard pack 50 psi loose graval/dirt 25-35 psi and mud/sand 5 psi and for wet slipper boat ramps about 15 psi... I do have bead locks so dont run urs this low unless U also have bead locks..

 

I run Goodyear Eagle GT-II's all around. P235/60R15 front; P295/50R15 rear. They have a recommended pressure of 35 psi. I have been keeping them at 35 front (so I can steer it in tight spots) and 30 rear (to soften the ride some). I think I'll try dropping everything about 5 psi to see what happens to the ride quality.

I have run the rear as low as 15 psi, but that was for more traction at the drags.

 

UPDATE: Dropped everything 5 psi (30 front, 25 rear). The ride is much improved.

 

Yes, & by Dropping that Air Pressure you Increase Drag, there fore Increasing Petrol Consumption.
If you are running Proper Truck Tires, 6.50-7.10x15LT Load Range C @ 55psi.
One should be Inflating those tires using the Specs on those tires, which usually States 50-55psi.

 

The PSI rating on the sidewall of the tire is the maximum for that load range tire, and is an industry standard. Standard Load, "P" metric tires will have a max psi of 35, regardless of size, manufacturer, etc, and is not the recommended air pressure, only the max air pressure. Other load range tires, extra load, load range c,d,e etc, will have different max pressures, but again those are only maximums, not necessarly recommended pressures. If you're running a fairly large tire on your truck, and not carrying any weight, you can drop your pressures down for a smoother ride, and more even wear. If its used like a car, run car like air pressures. I see trucks all the time with large tires and worn out tread in the center from the tire "crowning". They put load range c (6 ply rating) tires on their truck, and ran them at the 50 psi max with no load. The edge of the tread barely contacts the pavement so the center of the tread wears rapidly. Same situation with larger 70 and 60 series. Since we don't have the door sticker telling us what pressure to run, we have to experiment. By the way, I'm assuming 15, 16" p-metric and lt tires here. Eighteen, twenty, and twenty two inch are a differnet story.

 

I find the correct air pressure by using chalk or grease pen the yellow wide marking pens work great. I make a mark from one side of the tread to the other and drive for a few miles. If the center is worn away and the outisde is still there the tires is over inflated for the load you are carrying. If the mark is gone on the edges and still in the center the tire is under inflated. Once I find the point where both happen I aim for a spot in the middle. Don't forget to do the front and rear seperatly

 

My tires state that they should be inflated to 44 PSI. I am running P235/75/16 front and back. I run them at 44 PSI. The ride is a little rough without a load, but once I get a load in it, the ride smooths out a bit.

 

I was hoping someone would point that test out. Thats the way I was taught to do it years ago. Don't go by labels on the vehicle or the tire. It makes them wear flat and even.

 

Chris/Brian - Thanks. The marking pen is a great idea that I never heard before. I will try that.

 

I cannot take any credit for the marking pen. Great idea, but not mine.