95 f250 hd .my truck has really ruff ride my friend told me to lower the psi in the tires. Currently I have 55 psi in tires what is the correct psi and how low can I go ?????

 

You need to read the psi setting on the side of your tires to get the psi number or consult the owners manual. To check to see if you have the right tires, look inside the driver door or the owners manual. Thats the maximum pressure on the side of the tire. You can safely lower it by 10%. If long hauling or towing run the pressure at the max setting.

 

Let me jump in here, the door says 80 rear, 55 front. Load range E tires on both. The tire says 80 lbs on it. If you can only lower the pressure by 10%, how does this work? What do you run in your tires? I run 80 in the rear, 65 in the front. Usually a trailer behind fwiw.

 

Its based on the actual load rating of the tire, when you are unsure of your load on the tires you should use the tire psig rating and can safely run less than 10% of the tires listed pressure. If you load is greater than the listed tire load/psig rate then of course its not correct.

The door load/psig range is generally specific to the tires that were on the truck at the time that it was manufactured. If the tire are the same and the loads on the truck are still the same on your vehicle you can run using the doors pressure settings. Running the rear tires lower than the door setting will allow for some flex in the tires which can contribute to roll overs under exstream driving conditions.

All if your never towing where there is added load on the rear you could run at reduced pressure. But when towing if you have to brake hard shifting the load more to the front then use the tire set pressure and not the door listed pressure. The 10% rule can still apply.

Also running near the set pressure rating reduces frictional heat loads.

Hope that helps clear that up, but let me know if I muddied the water.

 

I more/less get what you're saying. My thought was, 55 seems too low, but no need for 80 in the front, especially when towing, considering all the weight transfer to the rear, the front doesn't have near the weight as it does empty. If I drove empty much, I'd set them all at 75-80 and go...

 

I take white shoe polish and put a line across the tire and keep lowering psi till it wears even for truck only for me it's 47psi rear 55 front when i'm towing i run 80psi rear 65 psi front

 

I do something very similiar to fordpride. I use a tire tread depth gage and monitor tire wear. For my 97 F250 with 18" E rated Hankooks on, I run 40 PSI rear and 55 front. Now this is only if I'm just be bopping around and taking it easy. When I load up to 18 to 21,000 lbs of towing weight, then my PSI goes back up to max pressure. Before I made the change, my ride was rough and the center of my tires were wearing much, much faster than the sides. I did not notice a drop in MPG nor have I seen an increase in tire temperatures. Again, though, you cannot go out and race with lowered tire pressures as sidewall flex can cause a tire to peel off the rim. Hope this helps.