Gearing formula question

[Ozwynn]

this is for you math wizzes. my tire size is 295/75/22.5 (39.4"). I am turning 1700 rpms @ 55 mph in what should be my direct drive gear. what are my gear ratios?

 

[martin]

would you verify that tyre size again as it works out to fourty inches, also 1700 rpm at what speed?

 

[Ozwynn]

I edited, I checked it with the tire size calulator, I got 39.4"...... 55mph ..... this is for my new freightliner.... no axle tag and i need to know the gear ratio.

 

[Hahnsb2]

3.55ish, it would be a bit more accurate if you measure the tires with a tape, they usually never measure out to what they're supposed to...

 

[Ozwynn]

ok thanks, that would be 3.58's (common in a freightliner).