| Most go kart racers know about gear ratio and racing | | | | To figure IPR use this equation: Rear Tire |
| go kart gear ratio charts are listed in numerous places. | | | | Circumference(T) x clutch gear(C) divided by rear |
| Racing go kart gear ratios are figured using the | | | | gear(R) = IPR. For example if one racer(Racer A) |
| number of teeth on the rear sprocket of your go kart | | | | was running a 15t clutch gear with a 60t rear gear and |
| divided by the number of teeth on the clutch gear on | | | | their tires were 34" the equation would be 34 x 15 / 60 |
| your go kart engine. For example if you were running a | | | | = 8.5. This means the kart would travel 8.5 inches per |
| 15t clutch gear and a 60t rear gear it would be 60 / | | | | revolution of engine. If another racer(Racer B) had the |
| 15=4. Simply put this means 1 revolution of the axle to | | | | same gears but had 36" tires look what happens. 36 x |
| 4 revolutions of the crank. | | | | 15 / 60 = 9.0. |
| But in order to get a true picture of a racing go kart | | | | Even though both these racers were using the same |
| gear ratio a karter must use rear tire circumference in | | | | gears they were not running an equal set-up. Racer A |
| the equation. If a kart racer is using the same gears as | | | | would be faster coming off the corners and Racer B |
| someone else but you have 34" rear tire | | | | would be faster down the straight. So what if Racer B |
| circumference and someone else has 36", the true | | | | wanted to run the same IPR as Racer A but still use |
| ratios are not equal. To figure the true ratio you will | | | | the same tires? To figure that we can replace Racer |
| want to use IPR (inches per revolution) which simply | | | | B's 60 with Racer A's IPR. 36 x 15 / 8.5 = 63.52. This |
| means the number of inches a kart will travel per each | | | | means that for things to be equal, Racer B would need |
| revolution of engine. | | | | to change their rear gear to a 63t or 64t. |