Sure. 
First, a question:
How far would a robot (with 4" wheels) go if its wheels each rotated for 1 revolution?
This first one is pretty easy, it’s just the circumference of the wheel (D*π) so…
3.141… * 4 = 12.546"
Now, add velocity:
We know that for every revolution, the robot travels about 12.546". If we also know that the robot’s maximum speed is 257RPM, then this means that every minute the robot’s wheels make a full revolution 257 times.
257 revolutions is also 3,224.322" of wheel travel (257 * 12.546"). the units of this measurement is Inches per minute. but we want inches per second, so since there are 60 seconds in a minute, we simply divide this by 60:
3,224.322" / 60 = 53.74 IPS (inches per second).
A while back, I wrote a python script to generate a text file which contained every conceivable gear ratio, motor cartridge, wheel size combination, and the inches per second of each combination.
Now, the vast majority of this file is next to useless since nobody in their right mind is going to make a robot with 2.75" wheels powered by a torque motor geared down 12->84… or, on the flip side, nobody in their right mind would make a drivetrain with 4" wheels powered by a turbo motor geared up 84->12… but still, if anyone wants it:
ratios.vex (26.0 KB)
(The file extension is a .vex because vex forum wouldn’t let me upload a .txt. The file is just a plain text file, you can open it with notepad (or TextEdit if you are on mac)).
Now, there are other, better, resources then the one I shared. Here’s one:
I remember finding one that included a google sheets (I liked that one , but I can’t find it)