4lo gear calculator questions

[buffblazer]

so i posted up my D-max in a different thread and im considering re-gearing since it has 37's on it.


im confused because when im on 4lo this is what i get if i try to enter the tire size as standard and metric.

New Tire Diameter 37
Old Tire Diameter: 30.5
Current Gear Ratio: 3.73

Effective ratio 3.07:1


now if i enter it as metric its a completly different ratio

New Tire Diameter: 356
Old Tire Diameter: 245
Current Gear Ratio: 3.73

Effective ratio: 2.57:1


now a 245/75/16 was stock height and changes to a 30.5 tire.
a 37 inch tire is 356 in metric


so why is my effective ratio different? which one is the true ratio?

 

[gone huntin]

You use the tire height in inches, not metric. You need 4.56 gears.

 

[buffblazer]

You use the tire height in inches, not metric. You need 4.56 gears.

i know i need 4.56 gears but im curious about the ratio outcome if the calculator is true

 

[4X4HIGH]

Post up a link to the calculator you're using.

 

[buffblazer]

Post up a link to the calculator you're using.

http://www.4lo.com/calc/geartire.htm

http://www.4lo.com/calc/gearmetric.htm

the second link is the converter for metric to standard. I dont know if im entering the info wrong or what.

 

[Roadhazardguy]

Maybe this one: http://wahiduddin.net/calc/calc_speed_rpm.htm

Guess not

 

[Duntz00]

Check this one out, its the one I use....

http://www.grimmjeeper.com/gears.html

 

[djtejas]

so i posted up my D-max in a different thread and im considering re-gearing since it has 37's on it.


im confused because when im on 4lo this is what i get if i try to enter the tire size as standard and metric.

New Tire Diameter 37
Old Tire Diameter: 30.5
Current Gear Ratio: 3.73

Effective ratio 3.07:1


now if i enter it as metric its a completly different ratio

New Tire Diameter: 356
Old Tire Diameter: 245
Current Gear Ratio: 3.73

Effective ratio: 2.57:1


now a 245/75/16 was stock height and changes to a 30.5 tire.
a 37 inch tire is 356 in metric


so why is my effective ratio different? which one is the true ratio?

Where you are using 245 and 356 as diameter is what is messing you up...on a size 245/75/16 tire 245 is tire width in millimeter not the diameter
in the second one where you input metric you used the wrong numbers, you input the width instead of diameter...so the calculation comes out different

 

[Hogback Fabrication]

so why is my effective ratio different? which one is the true ratio?

You are using the section width, in millimeters, as your tire height.

Convert your metric tire sizes into metric or english unit heights and you'll get the right numbers.