tire pressure on 20's?
 

I have 285/55/20 BFG AT's. I have a steering wheel vibration at 60-70mph. What tire pressure should I have the tires? They are currently at 37psi. Yes, they have been roadforced balanced 15, 25, 35, and 37. BFG will not replace the tires that are 35/37 they say below 39 is normal, eventhough Ford says below 25.

Pressure may be a bit much. I would suggest about 32. Have your wheels torqued with a torque wrench. Never let a shop use an impact to tighten alloy wheels, allways insist on hand torqued.

The size you mentioned are a Load Range D tire. Tire pressure for that LR on an F150 should be about 44-46.

O.K., one says 32, one says 44-46, anyone want to be a tie breaker?

35 is average, if you need to two or carry a load i suggest bumping up the rear t about 42-44 :thumbsup:

Well the new regulations for tire pressure monitors state that the alarm should go off at 35 for a LR D that has a max of 65. I have LR C on my F150 and the pressure on the door is 40. When I ran LR E's, I ran them at 50 and that was right for my truck.

Well I've had the 285-65-18's on my screw for awhile now and run them at 45psi. The ride is not bad at all and wear seems fine.I did the chalk mark test and at 45 psi they wear even all across. The stock tires called for 35 psi but load range D tires should always be in the 40's minimum. Just my .02

40psi would be a good starting point for daily driving.

Here's my theroy............
You now have a much larger tire contact patch. As long as you are not towing, or hauling a great deal of weight, the higher pressure is not needed as you have a greater area supporting the weight of the truck. You will get varied opinions, you should check with a tire store you trust and get their opinion.

I have the same tires and had the same problem. Got them road forced balanced yesterday and the problem has gone away. I don't know if it makes any difference but my tire pressure is at 40. That's what they told me it should be at the tire store. Good luck - I know it's a pain.

My 2005 FTX Screw came with 305/55-20s and the factory sticker and the additional Tuscany sticker both say 40psi. Seems to ride and feel just like a new stock F-150 with factory 18s.

What brand and load range tires? Also, if these items were added by the dealer, they would not match the door sticker. Does the door sticker say tire size of 305/55-20?

I have 305/50/20 nitto terra grapplers and I run 40psi.