Thanks Jim for the calculator
Gear ratio calculator that some might find handy.
The program can be downloaded from Index of /ratiocalc
Just right click on the file gearratio.exe and select "save link as" and put it somewhere you can find it again. Once it's saved, double click on the gearratio.exe file and it will run.
The program allows for up to three ratios in series. If you have fewer just leave the unused ratios set to 1:1.
The program will also calculate speed based on engine RPM, drive ratio,and wheel diameter. Be sure to measure the outside diameter of your wheel for accurate results.