## 72t Calculator

Question: help with gear ratio please!!?

so im trying to figure out a good gear ration so im using a speed calculator which tells u the speed of your gear ratio and i tried two different ones and they both give me different answers so can u tell me which one is right??

the first one is: http://www.diygokarts.com/speed-calculator.html

and the second one you have to click one write up then on engine then at the bottom click on the link and it will take you to calculator: http://sadik.net/gokart/

in the first one it game me … for 12t clutch and 72t on axle and a tire circumference of 30 and a rpm off 5000 it gave me 74mph.. and the second one game me 23.67424 mph so which one is right??

Answer: (60 minutes/hour * 5000 rpm * (12 / 72) * 30 inches) / (12 in/ft * 5280 ft/mile) = 23.6742424 mph

I confirm the one that says nearly 24mph.

Note, the problem with the diygokarts was it asks for Diameter not Circumference. Diameter would be 30/3.14, and your result of 74mph is off by a factor of pi~3.14

74 / 3.14 = 23.566879