Mr. Gasket 8703 Hot Rod Calculator User Manual
Page 42
40 —
H
ot
r
od
C
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™
* Repeated presses of
will toggle through the inputs and outputs,
starting with the current final-drive ratio input.
— do noT Clear CalCUlaTor —
** The effect to the final-drive (
d-eff) of going from a tire diameter of
28.9 to 33 inches is an estimated ratio of 2.697, which will create a fair-
ly noticeable loss in your four-wheeler pickup from a stop or while roll-
ing down the highway. To get back to a similar responsiveness on the
new 33 inch diameter tires, you would want to install a set of final-drive
gears closer to a 3.5 ratio (
d-eQV).
next, calculate the effect of the tire change to your speedome-
ter. you made the switch to the 33 inch tires, and you want to
know what your actual speed will be with an indicated (gauge)
speed of 65 MPH.
KeysTroKe
disPlay
4. Enter the target indicated (gauge) speed of 65 MPH:
sPeed 65.
MPH
5. Calculate the effect to speedometer:
Tire
raTio
1.142
(Final-drive ratio)
d-eff
raTio
2.697
(Equivalent drive ratio)
d-eQV
raTio
3.517
(Actual speed)
SPD►A 74.221
MPH
**
(Gauge speed)
G►SPD 56.924
MPH
*
sPeed 65.
MPH
* Repeated presses of
will toggle through the inputs and outputs,
starting with the entered current final-drive ratio.
** For the entered indicated (gauge) speed on your speedometer of 65
MPH, the actual speed is 74.221 MPH
(
SPD►A)
after switching from
28.9 to 33 inch diameter tires. So, if you want to be going the legal 65
MPH, you want your speedometer to read about 57 MPH
(
G►SPD).
(cont'd)
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