Please Explain Gearing (Rear End)

[POWERMAN]

Very informative thread..thank you for this!

I know it's not possible..but imagine if folks figured out a way in which one could select what kinda rear axle ratio they wanted at the push of a button?

Just thinking out loud... : p

[AFPVet]

Another thing to remember is that every engine 'likes' a particular rear gear. If you over- gear your engine, you end up with what Hazmat said. If you're crossing the line at the time when your engine is no longer making horsepower (torque X RPM/5252), you aren't gaining anything. Your ideal rear gear will allow you car to be in the power band when it crosses the line. Too long of a gear = not optimum... too short of a gear = not optimum. You want a good balance between.

[hangn0ut]

Commercial trucks have 2 speed drive axles. Use it to split the transmissions gears for heavy loads. That's a lot of shifting. Regarding top speed, a lower gear, numerically, does not necessarily mean a faster car. You got to have the horsepower to pull a tall gear. Power needs go up drastically to go fast. 150 might get touched, but not for long!

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[dejuan7]

Originally Posted by michiganpat

what tranny do you have? 42RE has a .69:1 OD, making your 3.64's an effective 2.51 overall top gear ratio. the NAG1 5 speed has a .83 OD, turning the 3.64 into an effective 3.02 overall top gear

28" tall tires with 3.64's would put 5000 RPM at 138 MPH with a NAG1, and 166mph with a 42RE

the 42RE has a 2.74 first gear, whereas the NAG1 has a 3.59 first gear...so....

a 42RE with a 3.64 has an overall first gear ratio of 9.97:1
a NAG1 with a 2.82 has an overall first gear ratio of 10.12:1
a NAG1 with a 2.65 has an overall first gear ratio of 9.51:1

Nag1 i was talking about on the highway...Not 1/4 It gets to 130 rather quickly but hell im scared to push it pass it not sure if it could or not lol.