Tire Size Box

195/40R16 vs 195/45R16

195/45R16 compared with 195/40R16

+3.5% diameter, 0.0" width

195/45R16 is 22.91" tall vs 22.14". More than the 3% rule of thumb, so check carefully before switching.

22.1"16" rim3.1"7.7" wide
195/40R16 (solid) compared with 195/45R16 (dashed outline), drawn to scale

With 195/45R16 tires, when your speedometer says 60 mph you are really going

62.1 mph

195/45R16 is +0.77 inches (+3.5%) in overall diameter. That is more than the 3% most shops and makers recommend.

195/40R16195/45R16Difference%
Overall diameter22.14"22.91"+0.77"+3.5%
Section width7.68"7.68"0.00"0.0%
Sidewall height3.07"3.45"+0.38"+12.5%
Circumference69.56"71.97"+2.41"+3.5%
Revolutions per mile910.9880.3−30.5−3.4%

Speedometer difference

If your vehicle came with 195/40R16 and you fit 195/45R16, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.7 mph+0.7 mph
30 mph31.0 mph+1.0 mph
40 mph41.4 mph+1.4 mph
50 mph51.7 mph+1.7 mph
60 mph62.1 mph+2.1 mph
65 mph67.3 mph+2.3 mph
70 mph72.4 mph+2.4 mph
75 mph77.6 mph+2.6 mph
80 mph82.8 mph+2.8 mph

Each size on its own

Questions

Which is bigger, 195/40R16 or 195/45R16?
195/45R16 is taller by 0.77 inches (22.91" vs 22.14"). 195/40R16 is the same width.
Can I replace 195/40R16 with 195/45R16?
It is not recommended without checking carefully. The diameter difference is +3.5%, 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 195/45R16 change my speedometer?
When your speedometer reads 60 mph with 195/45R16 fitted (calibrated for 195/40R16), your real speed is 62.1 mph. Your odometer will under-count miles by about 3.5%.
Will 195/45R16 lift my vehicle?
Ride height changes by half the diameter difference: +0.38 inches of ground clearance at the axle.

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