Here is what I get for standard tire and tranny combos, and for my vehicle:
Yr/Gear------Ratio-- Tire---- Tran----Speed--Conversion factor
----------------------Dia.----Ratio---@3K
83-86 1st----3.45----25.63----4.03----16.5----0.005484164
83-86 2nd----3.45----25.63----2.37----28.0----0.009325392
83-86 3rd----3.45----25.63----1.49----44.5----0.014833007
83-86 4th----3.45----25.63----1.00----66.3----0.02210118
83-86 5th----3.45----25.63----0.81----81.9----0.027285408
87-88 1st----3.55----26.63----3.97----16.9----0.005621319
87-88 2nd----3.55----26.63----2.34----28.6----0.009537025
87-88 3rd----3.55----26.63----1.46----45.9----0.015285368
87-88 4th----3.55----26.63----1.00----66.9----0.022316638
87-88 5th----3.55----26.63----0.79----84.7----0.028248909
Walsted's 1st----3.55----26.10----3.97----16.5----0.005509442
Walsted's 2nd----3.55----26.10----2.34----28.0----0.009347215
Walsted's 3rd----3.55----26.10----1.46----44.9----0.014981153
Walsted's 4th----3.55----26.10----1.00----65.6----0.021872484
Walsted's 5th----3.55----26.10----0.85----77.2----0.025732334
Here is what I come up with. Multiply your RPM by the conversion factor to get your speed. The Speed column is speed at 3,000 RPM. The third set of numbers for my car is because I have a 87 'n/a mustang tranny, 3.55 gears, and will be getting 235/60R15 tires.
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Mike Walsted
1986 5-speed TurboCoupe .
[This message has been edited by Walsted (edited 07-22-2001).]