Gear Ratio change for fuel savings.

Transmission Ratio RPM Calculator | Spicer Parts

Something dosent sound right with your numbers.

4.11 gears
44" tire if your running 11r24.5's
1600rpm
.73 high gear
Puts you at 69.83mph according to this calculator. Now in you are running lowpro 24.5's or 42" tire it puts you closer to your number at 66.66 mph. But if you are at 11r24.5's then 4.33 would be closer to your numbers. Unless your speedometer is off.

 

Is your speedometer faster or slower then the gps? At any rate with a 10sp I wouldn't drop and lower then 3.7x gears. It will drop you out of your RPM band and make your mileage worse. If you had a 13 it would give you a little better options. Just gotta remember if its not a CAT you gotta run a little higher in rpms for better performance.

 

Fierce Fuels X1 is it it's 4th year of test market. It is a proven fuel system optimizer (no additives) along with other great benefits. Again, they have worked to get this fuel optimizer right. Check it out on YouTube, Ron tells his story. Copy and paste the following link.

You can contact me at aja3100@gmail.com for more info if you are interested. This is the "real deal"!
Good luck on saving money every trip.