If the final axle RPM is 148RPM and the tyres are 87" circumference (roughly 7' 3") then each minute it moves 148 * 7.25 feet = 1073 feet per minute.I am using 2000 rpm as a low reference point (this depends on the two speed selection) as 4500 rpm on the motor is probally dependent on the two speed selection.
this needs to be investigated. Will do when I get my new sprockets installed.
There is no jackshaft in my configuration, just the 13.5:1 differential ratio.
2000(rpm)/13.5(diff ratio)= 148.148 axle rpm. the fat tires are 87" in circuference so every miniute the tire rotates 148 rpm which equates to 148"/12=12.34 feet the cart moves per miniute at 2000 motor rpm.
hope this helps describes my configuration.
1073 feet per minute x 60 = 64,380 feet per hour. 1 mile = 5280 feet so the speed would be about 12.19 MPH. which is a nice speed to bimble along at.