2011 Rim And Axle Ratios

godfather55v · June 1, 2011

looking at two 2011 identical trucks other then one has 20" rims w/ a 4:10 and the other has 18" and 3:73 would the rim difference be about the same as what you lose in the gearing.

I currently have a 2008 3/4 ton w/ 3:73 and 17 factory rims and love how it pulls, and really don't want to go backward in fuel mileage as i'm only pulling 10% of the time.

thnaks for your input

Big Whiskey · June 1, 2011

Well, the size of the rim doesn't really have any effect on MPG...it's the overall diameter of the tires that makes a difference. Find the two tire sizes and use a site like http://www.miata.net/garage/tirecalc.html to check the overall diameter.

Rat4go · June 16, 2011

the factory 20" tires and the 18" tires are very similar in outer diameter to each other. Odds are your 2008 has 265/70-17's on it if the tires are stock. Your current tires are a bit shorter than the stuff on the new trucks, so assuming everything is equal, the new truck with a 3.73 axle (like your current truck) will work a bit harder for the same load, but will spin a few less RPM with the same axle. If you're happy with a 3.73 in your current truck, odds are you'll be just as happy with the perf of a 3.73 in the new truck. Dunno how the new truck will compare from a MPG perspective, even with the same axle. It's a fair bit heavier (for the same body style) which is the wrong way for MPG.

SparkySparks · June 16, 2011

Don't you also have to take the fact that the new truck will have the 6 speed where as his 08 had the 4 speed? I thought I saw someone post that the new 6 speed with 3.73 is better then the old 4 speed with 4.10, both in towing and mpg.

Stevens03 · June 16, 2011

I think your over thinking it. The weight difference between the 2 is very small.

pknoerzer · June 17, 2011

Don't you also have to take the fact that the new truck will have the 6 speed where as his 08 had the 4 speed? I thought I saw someone post that the new 6 speed with 3.73 is better then the old 4 speed with 4.10, both in towing and mpg.

The 2008 should have the 6-speed. My 2007 does.