Tire Size Box

305/35R22 vs 305/45R22

305/45R22 compared with 305/35R22

+7.9% diameter, 0.0" width

305/45R22 is 32.81" tall vs 30.41". More than the 3% rule of thumb, so check carefully before switching.

30.4"22" rim4.2"12.0" wide
305/35R22 (solid) compared with 305/45R22 (dashed outline), drawn to scale

With 305/45R22 tires, when your speedometer says 60 mph you are really going

64.7 mph

305/45R22 is +2.40 inches (+7.9%) in overall diameter. That is more than the 3% most shops and makers recommend.

305/35R22305/45R22Difference%
Overall diameter30.41"32.81"+2.40"+7.9%
Section width12.01"12.01"0.00"0.0%
Sidewall height4.20"5.40"+1.20"+28.6%
Circumference95.52"103.07"+7.54"+7.9%
Revolutions per mile663.3614.7−48.6−7.3%

Speedometer difference

If your vehicle came with 305/35R22 and you fit 305/45R22, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.6 mph+1.6 mph
30 mph32.4 mph+2.4 mph
40 mph43.2 mph+3.2 mph
50 mph53.9 mph+3.9 mph
60 mph64.7 mph+4.7 mph
65 mph70.1 mph+5.1 mph
70 mph75.5 mph+5.5 mph
75 mph80.9 mph+5.9 mph
80 mph86.3 mph+6.3 mph

Each size on its own

Questions

Which is bigger, 305/35R22 or 305/45R22?
305/45R22 is taller by 2.40 inches (32.81" vs 30.41"). 305/35R22 is the same width.
Can I replace 305/35R22 with 305/45R22?
It is not recommended without checking carefully. The diameter difference is +7.9%, more than the 3% most shops and makers allow. It will throw off the speedometer and may affect ABS, stability control and clearance.
How much will 305/45R22 change my speedometer?
When your speedometer reads 60 mph with 305/45R22 fitted (calibrated for 305/35R22), your real speed is 64.7 mph. Your odometer will under-count miles by about 7.9%.
Will 305/45R22 lift my vehicle?
Ride height changes by half the diameter difference: +1.20 inches of ground clearance at the axle.

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