Hi guys, I did a search but could not find out what I wanted. Is there anyone running 40s on there V10 and what gears do you have? My truck has stock 4:30s right now and I have 37s with a 6 inch lift. I play in the mud some, I pull people out the mud ( mostly diesels lol) and I tow 4 wheelers and lawn mowers . Up sizing my lift and going to 40s (which I already have) next month , just wanted some real life experiences with gears, 40s, and the flutter 10 engine.

 

Gear Ratio Calculator http://www.grimmjeeper.com/gears.html

 

Your options for 40s are basically 5.13 or 5.38 gears. For what you tow and lack of higher rpm breathing of your NPI V10 you probably be better off with 5.13s. Use the calculator harley posted to see where your rpms will be compared to what you have, its the best one I have found.

 

Wow thanks guys. That is a good calculator! I was leaning toward 5.13 gears, this helps a lot .

 

Rule of thumb:

Divide new tire diameter by old tire diameter, and multiply by the current gear ratio.

That'll give you what your NEW ratio should be with the new tires, if you are aiming for the same overall experience.

 

Krewat, I used that formula you posted twice. Once with figuring in 40s and my OE tire size (about 31 inches tall) and my 4.30s and got 5.54 ratio,then I figured in 40s and my current 37s with 4.30s and got 4.64 ratio. Pretty handy equation.