Features Gear ratio rear end

I am trying to find out what gear ratio I need if I have 27” tires and at 70mph I would like my rpms to be about 2,000 or 2100


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Over drive tranny????.........T-5??? Little mo info needed
6sally6

 

Short tires are hard on rpm at speed.
27" at 70mph and a 2.3 gear equals 2057 rpm.

https://spicerparts.com/calculators/engine-rpm-calculator

That is without overdrive.

 

http://www.csgnetwork.com/multirpmcalc.html

I use this a lot. Simple google search for rpm calculator

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tranny final drive ratio?

 

Just roughly it sounds like you are going to be in the range of about 3.3 to 3.5:1 going by what my F100 with T700R4 does on 235/75/15 tires. I'm running 3.54:1 gears.

 

Here's one I wrote.
You can use it online or download it.

https://docs.google.com/spreadsheet...edit?usp=drive_web&ouid=112198810104839318872

 

2100 RPM @ 70 MPH with 27” tire and w/o overdrive you would need a 2:41 gear.

 

FWIW.
I have a T5 with 0.86 OD, 27" rear tires and a 3.73 rear. 55mph is about 1750 rpm
Chappy

 

You could also look up the formula yourself.

 

Nope