3:73 vs 4:10 gears

[jjakes2003]

New to the forum. I am about to buy a 2004 Sierra 1500 ext cab shortbed w/5.3L and quadrasteer. I had a choice between a vehicle with 3:73 rear end and 16in wheels and one with 4:10 rear end and 17in wheels. I went for the 4:10 because that was the color combination I wanted in the vehicle. I was told that the 3:73 would give me a better or smoother highway experience and better gas mileage. Since the RPM's would be lower. It would be better for the life of the engine as well. I have a 45 to 60 mile commute each day to different locations. Will the 4:10 with the 17in wheels be that much worse than the 3:73 with the 16 in wheels in regard to gas mileage and highway ride?

[carl722]

It doesn't matter that much when you are going to increase your wheel diameter by an inch. Your tire size effects your gear ratios. The taller your tires are the more it cuts back your gear ratios. If your tires are too tall for 3.73 your engine will actually work harder to do the same work as the 4.10 thus using as much or more gas. Here are some formulas on how to fugure your gear ratios:

 

Formulas

 

gear and tire charts

 

The one above click on the gear/tire size table and that will give you alot of info on how to pick your gears. I have 2 vehicles with 3.73 and one I wish was a 4.10 and the other I am going to switch to 4.56