Anybody know the formula?

 

Ok, so for the following:

195-60-14
1. Sidewall height (in mm) = 195 * .60 = 117 mm
2. Sidewall height (in inches) = 117 mm / 25.4 = 4.606 inches
3. Outer diameter (in inches) = 14 + (2 * 2.971) = 23.21 inches

Did I do the calculations correctly?

This is a 14" azenis on stock hx rim... I wanna see how the acceleration is affected compared to stock rims and tires... with the same engine and tranny combo...

[edit] fixed calculations..... [/edit]


[Modified by Black R, 7:16 PM 3/7/2003]

 

.....ok, I see what you did.

I've had this formula for a long time (how to calculate the total height of a tire):


{[(tire width) * .(tire aspect ratio) * 2] / 25.4} + (rim diameter) = total tire height


So, 215/45/16 would look like this:

{[(215) * .(45) *2] / 25.4 } + (16) = 23.6

But how does this affect the acceleration? I mean, how does it make the 4.4 final gear feel now? (compared to stock tires at 23.44 height?)

 

smaller diameter (compared to stock) = shorter (numerically higher) final drive
larger diameter = longer (numerically smaller) final drive

23.6>23.44 therefore you would have a longer final drive. but the difference there does not seem significant to affect acceleration much.

 

don't have the equation.. but you can get some idea of how things will be when you change tire diameter - i placed different tire sizes with 4.4 final drive - but you can change it around..

http://bob123e.tripod.com/askbob/Gea...Calculator.htm