RPM/Tire size/Gear ratio Calc.
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Joined: Feb 2006
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From: Va.
RPM/Tire size/Gear ratio Calc.
Just for info on tire size and gear changes, thanks to Drive Train Specialist. http://www.drivetrainspecialists.com/
I think our OD final drive is .690. Someone might need to correct me on that one.
Q. How can I determine what ratio to use for my application?
A. mph x gear ratio x trans ratio x 336 รท Tire Diameter = RPM
Tire Diameter
Example:
70 mph x 3.73 (gear ratio) x .67 (trans ratio) x 336 รท 27(tire diameter) = 2176RPM
70 mph with a 3.73 ring and pinion over drive transmission in 4th gear with a 27" tire will perform at 2176 RPM
I think our OD final drive is .690. Someone might need to correct me on that one.
Q. How can I determine what ratio to use for my application?
A. mph x gear ratio x trans ratio x 336 รท Tire Diameter = RPM
Tire Diameter
Example:
70 mph x 3.73 (gear ratio) x .67 (trans ratio) x 336 รท 27(tire diameter) = 2176RPM
70 mph with a 3.73 ring and pinion over drive transmission in 4th gear with a 27" tire will perform at 2176 RPM
Joined: May 2004
Posts: 3,811
Likes: 3
From: Bett-neee
RE: RPM/Tire size/Gear ratio Calc.
yea your right
i just did mine and im damn near dead on
mph x gear ratio x trans ratio x 336 รท Tire Diameter = RPM
Tire Diameter
75X4.10X.690X336/29.4=2424 RPM and thats right about what i see when im driving... rpm's will go down when i get bigger tires for example
mph x gear ratio x trans ratio x 336 รท Tire Diameter = RPM
Tire Diameter
75X4.10X.69X336/33=2160 so in my case with my rear gearing when i go to my larger tires in the spring/summer my mileage might get a smidgen better... depending on how much harder the motor will have to work to spin the bigger rubbers...
essentially you can do this with all the gear sizings through out the 46RE and see what rpms you should be at in every gear at certain speeds... it just depends if that fixed numer 336 would change or not... dont think it would though
i just did mine and im damn near dead on
mph x gear ratio x trans ratio x 336 รท Tire Diameter = RPM
Tire Diameter
75X4.10X.690X336/29.4=2424 RPM and thats right about what i see when im driving... rpm's will go down when i get bigger tires for example
mph x gear ratio x trans ratio x 336 รท Tire Diameter = RPM
Tire Diameter
75X4.10X.69X336/33=2160 so in my case with my rear gearing when i go to my larger tires in the spring/summer my mileage might get a smidgen better... depending on how much harder the motor will have to work to spin the bigger rubbers...
essentially you can do this with all the gear sizings through out the 46RE and see what rpms you should be at in every gear at certain speeds... it just depends if that fixed numer 336 would change or not... dont think it would though