Enthusiast Tools
Tire Size Calculator
Compare tire sizes, calculate speedometer error, and see how changing your wheel setup affects your vehicle's ride height and gearing.
Current Tire Size
225 / 45 R17
New Tire Size
245 / 40 R18
Speedometer Impact
Speedo Reads
65 mph
Actual Speed
66.9 mph
Specifications Comparison
Spec
Current
New
Difference
Diameter
24.97"
25.72"
+0.74" (3.0%)
Width
8.86"
9.65"
+0.79"
Sidewall
3.99"
3.86"
-0.13"
Circumference
78.5"
80.8"
2.3"
Revs / Mile
808
784
-23
Ride Height
-
-
Raised by 0.37"
