Tire pressure for daily drive

[RealJakeMalloy]

What tire pressure do you guys run to max gas mileage for daily driving? My 1976 isn't lifted. I have 31 inch tires.

 

[Tom Hartz]

For me mileage was never a thing in older off road vehicles. I do a chalk test. Take some chalk and cover the tread side to side. Drive the vehicle straight for 100 feet or so and look at the tread to see where the tread contact is. You want as much contact for safety, maximum pressure without over inflating the tires. Do this for the front and rear.

 

[Broncobowsher]

I once had an old International. There was a whole table for different tire pressures for different loads and sizes. Modern cars it is dumbed down to a single number. About 25 years ago I remember watching tire pressures jump from 26 to 35 for the exact same vehicle and tire. There is no magic single number. As much as people tell you to do the chalk test, it doesn't tell the whole story.

For a pretty generic 31" tire on a generic Bronco, guessing old school 10.50 width, try 30 PSI. That should be firm enough to keep the rolling resistance reasonably low, but not too hard. 32, 35 would probably also work. By the time you are at 35 you might be riding the crown of the tire a little too much. Short term gains in lower rolling resistance offset with uneven tire wear.

With the economy of these rigs, you won't see any change with minor tire pressure differences.

 

[RealJakeMalloy]

I once had an old International. There was a whole table for different tire pressures for different loads and sizes. Modern cars it is dumbed down to a single number. About 25 years ago I remember watching tire pressures jump from 26 to 35 for the exact same vehicle and tire. There is no magic single number. As much as people tell you to do the chalk test, it doesn't tell the whole story.

For a pretty generic 31" tire on a generic Bronco, guessing old school 10.50 width, try 30 PSI. That should be firm enough to keep the rolling resistance reasonably low, but not too hard. 32, 35 would probably also work. By the time you are at 35 you might be riding the crown of the tire a little too much. Short term gains in lower rolling resistance offset with uneven tire wear.

With the economy of these rigs, you won't see any change with minor tire pressure differences.

I don't care about mileage in so much as I know it will suck. Mostly, I want the truck to be safe and comfortable. Right now when I hit a bump it is teeth rattling.

 

[Broncobowsher]

Rattling teeth, what do you have the tire pressure set to now? Are they load range E tires? What is the rest of the suspension?

Now that we have an idea of what your problem is and what you are trying to fix, we can actually diagnose it and figure what is going on.

 

[Apogee]

As noted above, tire pressure is just one variable of many that factory into the overall ride quality of your rig. I will say that for my EB, the biggest difference in ride quality was achieved with more modern springs (coils and leafs), better shocks and better seats. Going to a CAGE (Duff style) extended radius arm helped as well with respect to the square edged bumps and such, but increased body roll somewhat, so there's some give and take. I was rolling 33's at the time, but increasing tire diameter also helps with respect to small bump compliance, especially off-road, noting that I'm moving towards 37's now, more for ground clearance than ride quality, as they are significantly heavier (unsprung weight) with the bigger tires and beadlock wheels.

 

[m_m70]

BFG 33x12.5 AT
Daily driver with no gear/weight in rear
28 front
26 rear