Changing Tires Project

By: Cassady Sawyers and Eni Labinjo

Factory Tire Information

Width of tire: 254 mm


Aspect ratio: 70%

17 inch rims

Replacement Tire

Tire width: 305 mm


aspect ratio: 55%

Rim: 20 inches

Factory Miles per Gallon

17 city/ 21 hwy mpg


"K" Ratio

*divide the circumference of the bigger tire but the factory tire


K= 1.1

If your odometer reading is 50,000 miles, you have actually traveled 55,000 miles on the new tires

*mutiply the k ratio (1.1) by the odometer reading (50,000)


If your speedometer reading 70, your speed is 77 miles per hour with the new tires

*multiply the k ratio (1.1) by the speedometer reading (70)


If your mile per gallon with factory tire is 21 hwy, what is your mile per gallon with the new tires?

*multiply the k ratio (1.1) by the factory mile per gallon (21 hwy)



New tire miles per gallon is 23.1 mpg