Use this calculator to see what your starting line ratio is.
You can also use a different tire height to see how it affects the SLR
(see the effects of tire height change without changing the rear gear ratio)
Starting Line Ratio Calculator
** - Input same tire diameter as the original tire diameter, if not changing tire diameters - **
A 9-10-11 range SLR is desirable.
The SLR of New Tire is what the SLR would be if taking the different tire diameter were taken into account.
(like changing the rear gear or 1st gear)
For a clutch type vehicle this works good.
Some racing automatics, the torque converter
has an effect on the ratio.
With a higher stall converter, the ratio can be smaller,
making a rear gear able to be a higher gear for more top end.