Tire and Gear Calculators

 When entering tire diameters, take into consideration the static loaded radius of the tire, not the overall manufacturers published diameter. For example, at correct pressure, my 32" BFG Mud Terrains have a static loaded radius of 14.625 inches. This gives an effective diameter of 29.25 inches. For accurate results, measure from the ground to the center of the axle, and multiply by 2 then enter that value into the calculators. This height can change depending on tire pressure (aired up on the street, and aired down off-road) and the speed of the vehicle (centrifugal force on the tire carcass).
 MPH Calculations RPM: Tire Diameter: Transmission Gear:  M/T 1st M/T 2nd M/T 3rd M/T 4th M/T 5th A/T 1st A/T 2nd A/T 3rd A/T 4th Transfer Case Gear:  2 Hi 4 Hi 4 Lo Axle Ratio:  I4 4.375 V6 XE No LSD 4.363 V6 XE w/LSD 4.636 V6 SE 4.636 MPH:
 RPM Calculations MPH: Tire Diameter: Transmission Gear: M/T 1st M/T 2nd M/T 3rd M/T 4th M/T 5th A/T 1st A/T 2nd A/T 3rd A/T 4th Transfer Case Gear: 2 Hi 4 Hi 4 Lo Axle Ratio: I4 4.375 V6 XE No LSD 4.363 V6 XE w/LSD 4.636 V6 SE 4.636 RPM:
 Speedometer Error Original Tire Diameter: New Tire Diameter: Speedometer Reading (MPH): Speed (MPH):
 Crawl Ratio Transmission Gear: M/T 1st M/T 2nd M/T 3rd M/T 4th M/T 5th A/T 1st A/T 2nd A/T 3rd A/T 4th Transfer Case Ratio: 2 Hi 1:1 4 Hi 1:1 4 Lo 2.02:1 4 Lo 3.92:1 Axle Ratio: I4 4.375 V6 XE No LSD 4.363 V6 XE w/LSD 4.636 V6 SE 4.636 V6 4.900 Crawl Ratio:
 P-Metric tire to inches Example: 195/75R15 LT /   R Tire Diameter:

These calculators are based on code created by Mark Medina - http://www.4lo.com/

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