I am a bit confused. Will this formula still apply for finding the sprocket I need when I am using treads. Velocity= Circumference*RPM. Then solve for RPM. Or does this only apply when using wheels?
It does apply, but the circumference used should be the circle of engagement of the sprockets.
You will probably have to calculate for the minimum and maximum circle (and then take the average), as the point of engagement is not really a point, but happens over a part of each cog as the wheel turns. If the wheel has seen some action, it will be easy to see, as the area will be "polished" by friction.
When I try and do this, I am getting a low number for the final RPM so I don't think I have the conversions, right?
It would be more informative to write the actual numbers you get.
Here is the info
Circumference of treads:69 in
Desired speed: 10mph or 10560 inches per minute
Drive Sprocket: 11 tooth
If you want to go about it from this info, you need to measure the length of track per cog and multiply by 11. Then multiply by rotational speed (RPM).
If each cog moves the track 5mm and the rotational speed is 500RPM, the resulting speed will be 2.5m/minute or 150m/h (0.15km/h)
Twice the track/cog or twice the rotational speed will give twice the speed and so on.