I have a 92 F150 4x4 with the 300.6 ( 4.9) I'm running 31-10.50x15 tires. I have 308 gears in it now, Do you thing going to a lower gear ratio would help the fuel economy?

 

Better around town, not better on the highway. That's a big reason why there were so many gearing options - so you can tailor your gearing to your intended use.

 

what gear ratio would you recommend for the best hwy and city economy

 

Suggest to consider the costs of changing two gearsets (front and rear, since 4x4) versus anticipated fuel savings.

IMO, changing gears solely for fuel economy reasons is an overall money-losing venture unless you plan on burning the hundreds of gallons and driving the thousands of miles to get back to break-even.

IIRC, the stock tire was 235/75, which should be a theoretical 28.9 inches tall. With your 31s, you're already down to a 2.87 ratio relative to stock tire size - not sure how much lower of a ratio you could stand before breaking out the Fred Flintstone booster feets to move it off the line after a stop. :-)~

Regardless of your interpretation of my attempt at humor - suggest fuel economy could be improved by changing gear ratios, but the tradeoffs and costs generally won't be worth it.

 

I did not think about it that way. tks for the tip