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Old 05-20-2019, 02:50 PM   #1
Gr8HallaFamer
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What is the RPM Revolutions per mile?

Can anyone tell me what the RPM revolutions per mile is on a 1987 700R4 transmission? I am in the process of fixing my speedometer which is off from changing the rear end and didn't know of this and already have taken my tail shaft apart. Not sure if knowing what color my gears are would help but I have a 17 tooth red Drive gear in the tailshaft and an orange Speedo gear.
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Old 05-20-2019, 03:09 PM   #2
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Re: What is the RPM Revolutions per mile?

Rpm per mile?....youd need alot more info to determine that....gear ratio,tire size,engine rpm
Your od ratio is .78...
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Old 05-20-2019, 04:29 PM   #3
geezer#99
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Re: What is the RPM Revolutions per mile?

Look in here.
They got gears, calculators, ratio adaptors etc.
https://transmissioncenter.net/
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Old 05-20-2019, 09:26 PM   #4
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Re: What is the RPM Revolutions per mile?

That looks like a good site geezer!....I'm gonna have to save this one...
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Old 05-20-2019, 09:44 PM   #5
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Re: What is the RPM Revolutions per mile?

Quote:
Originally Posted by Gr8HallaFamer View Post
Can anyone tell me what the RPM revolutions per mile is on a 1987 700R4 transmission? I am in the process of fixing my speedometer which is off from changing the rear end and didn't know of this and already have taken my tail shaft apart. Not sure if knowing what color my gears are would help but I have a 17 tooth red Drive gear in the tailshaft and an orange Speedo gear.
I ran this question through my computer and the answer that came out was 42.

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Old 05-21-2019, 09:49 AM   #6
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Re: What is the RPM Revolutions per mile?

If you are wanting to know the rpm of the speedo it is 1000.
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Old 05-21-2019, 11:49 AM   #7
Keith Seymore
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Re: What is the RPM Revolutions per mile?

Rev per mile is usually associated with tire size and is a function of rolling radius.

If you have access to the actual tire in real life you can measure it or determine through experimentation.

Otherwise you'd need to find the rev/mile info in a chart somewhere.

K
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Old 05-22-2019, 10:15 PM   #8
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Re: What is the RPM Revolutions per mile?

Depends what you're really asking for..

Tire Revolutions Per Mile = 20168 tire dia (inches)

Speedometer calibration for revolutions per mile = 1000 as mentioned above
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