8 replies to this topic

[Seabronc]

If you use the chart on your door post, that is the best pressure. Usually it is 35 lbs. If your tires are not stock, the manufacturer recommendations should be followed for best ride and wear characteristics. Usually a little lower presure is used off road to give better traction but they should be brought back up to road pressure before going back on the highway. Off road and highway are obviously two different things so you won't find a good pressure that satisfies both. If yoiu go low on the highway you will get poorer gas milage and excessive wear on the tires.

Good luck,

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[sweepersrgr8]

Look on the sidewall of the tire, it will be molded in, in fine print. My 31" recommend 50 lbs cold

[Broncoholics]

Every tire is different. Swampers feel the same at 15# to 35# due to heavy side walls. At 10 psi I feel a difference with the SX's so I run at 8-10# on the trail and air up to 20# on the road. Just my preference, I like a soft ride both on or off road.
BFG's and the rest are softer so I's say 30 psi is a good road ride/ handeling and some easy off-road stuff with good tire wear. Going off road for the day with these tires I'd say 15# so you don't debead, have good traction and can still drive on the road to the gas station for air.

[4xfan78]

NO! the number on the side wall of the tire is the MAX tire pressure. If you are using larger than stock tires then DO NOT go by the tire pressure info on the door. Doing either one of these will ruin you're tires. I have 35's on my 79 bronco and I put 28psi in the front and 25psi in the rear. It is allways best to use the same tire pressure gauge all the time and check the tire pressure every time you fill-up with gas.

[Seabronc]

I still say go by the tire manufacturer recommendations not the sidewall number for best wear characteristics. Any number I gave was just hypathetical. They are your tires and it's your money so if you want a mushy soft ride go low and accept the extra wear. Any professional selling tires can give you the right number for your tire size and weight.

[sweepersrgr8]

I know I am gonna piss everyone off here, but the tire pressure recommendation on the side wall of the tire, IS the manufacturers recommendation...THEY put it there. Also, being that it states COLD, it is NOT the MAX pressure as air expands as it heats up, and it is only a recommendation.

Like SEABRONC, and BRONCOHOLIC stated , play with the pressure to find what you like. These are only recommendations.

Also running low tire pressure on the highway increases body roll, which could lead to disaster ie. FORD EXPLORER.

[STLKIKN]

My 2cents...
The vehicle manufacturers recommended pressures are for:
1) OE tires (size and ply)
2) recommended load (the owners manual will tell you to vary pressures accordingly if you are towing/ hauling..
The tire mfgs recommended pressures are generally:
1) at maximum load capacity
2) maximum cold pressure at that capacity

For better fuel economy and handling on road, follow either the tire or the trucks pressure ratings, if your tire is only rated to 30 psi and the door decal says to run 35... only run 30.

For best tire wear...
Steal the neighbor kids sidewalk chalk.
Find a nice quiet straight stretch of road. (start with even tire pressures)
chalk all four tires, drive straight down the road. if the chalk wears off evenly you are done.
if the chalk wears off on the sides of the tread, you need more air, if the chalk wears off only in the centre of the tread, you need less air.
Continue this process until you have found the best chalk wear and you are done.
Examples... for on road use....
My 73 with 33 9.5 15s uses 30 front and 28 rear.
my 69 with 35 12.5 15s uses 21 front and 18 rear.

[Seabronc]

Hey, neat procedure STLKIKN Never would have thought of that