Final Drive Ratio Vs Rear End Ratio

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Rapid Randy Baker
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Final Drive Ratio Vs Rear End Ratio

Postby Rapid Randy Baker » Wed Mar 01, 2006 3:36 pm

I had this laying around and thought it might be interesting to some. This is how you calculate your Final Drive Ratio off the starting line.

If you have trans gear ratios of:

1st Gear = 1.31

2nd Gear = 1.38

3rd Gear = 1.00

Rear Gear Ratio of 3.90

You take the gear ratios and multipy them:

{1.31X1.38}=1.81 is your First gear ratio

Then take the first gear ratio times the Rear Gear ratio and that equals your Final Drive Ratio:

1.81 X 3.90 = 7.06

So your Final Drive Ratio is 7.06
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jim sanders
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Postby jim sanders » Wed Mar 01, 2006 4:01 pm

:?: :shock: :? :P

greenracing
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Postby greenracing » Thu Mar 02, 2006 1:07 pm

I thought I'd note that you're assuming a Lenco, where each section has a gear ratio and you put it in low by running through the accumulation of all of the sections.

If you have a standard tranny, or a TH400, or something similar, the ratios in each gear are usually stated directly because the tranny is only in 1 gear at a time. In this case, you don't multiply all of the gears together, you just use the low gear ratio x rear ratio.

Perry

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Rapid Randy Baker
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Postby Rapid Randy Baker » Thu Mar 02, 2006 1:16 pm

Perry, you are correct. I should have stated that in my post. We run a lencodrive in our car. The info is for that or a Lenco trans. Sorry,

Rapid
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jim sanders
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Postby jim sanders » Thu Mar 02, 2006 1:18 pm

:D

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Postby greenracing » Thu Mar 02, 2006 1:19 pm

no problem Randy. I understood, but I wanted to make sure no one else was confused.


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