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Tire Size, Circle.
This program will calculate the required tire circumference based on the old engine RPM, the
old tire circumference, the old gear ratio, the new engine RPM, and the new gear ratio.
Press CIR.TRK. FORMULAS, then Gearing/Tires, then select Tire Size to start this program.
Display Example:
== Tire Size ==
Old RPM? 7250 (Engine RPM was)
Old Tire? 89.00 (Tire circumference was inches - not diameter)
Old Gear? 5.13 (Final drive gear ratio was)
New RPM? 7500 (Desired engine RPM)
New Gear? 5.31 (Desired gear ratio)
New Tire= 89.05 (Calculated tire circumference inches to use)
Tire Stagger, Circle.
This program computes the required tire circumference for the inside drive tire based on the
race track turn diameter, the circumference of the outside drive tire, and the center to center
spacing of the drive tires.
Press CIR.TRK. FORMULAS, then Gearing/Tires, then select Tire Stagger to start this program.
Display Example:
== Tire Stagger ==
Turn Dia? 950' (Enter track turn diameter feet)
OutrCirc? 89.00 (Outside tire circumference inches - not diameter)
Tire Spec? 54.50 (Center to center drive tire spacing inches)
InnrCirc= 88.57 (Calculated inside tire circumference inches)
Chassis Setup by Percent.
This program computes the static weight to expect at each wheel of a vehicle for a given chassis
setup based on the total vehicle weight, the desired left side weight distribution percentage, the
desired rear weight distribution percentage, and the desired right front to left rear diagonal weight
distribution percentage.
Press CIR.TRK. FORMULAS, then select Chassis, then Setup by Pct to start this program.
Display Example:
==Setup by Pct ==
Car Wgt? 2250 (Enter total vehicle weight in pounds)
%Left? 58.2 (Enter desired left bias %)
%Rear? 47.0 (Enter desired rear bias %)
%Diagonal? 53.5 (Enter desired right front to left rear bias %)
Wgt LF= 649 (Calculated left front scale indication in pounds)
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