Tire Size Box

195/40R17 vs 195/50R17

195/50R17 compared with 195/40R17

+6.6% diameter, 0.0" width

195/50R17 is 24.68" tall vs 23.14". More than the 3% rule of thumb, so check carefully before switching.

23.1"17" rim3.1"7.7" wide
195/40R17 (solid) compared with 195/50R17 (dashed outline), drawn to scale

With 195/50R17 tires, when your speedometer says 60 mph you are really going

64.0 mph

195/50R17 is +1.54 inches (+6.6%) in overall diameter. That is more than the 3% most shops and makers recommend.

195/40R17195/50R17Difference%
Overall diameter23.14"24.68"+1.54"+6.6%
Section width7.68"7.68"0.00"0.0%
Sidewall height3.07"3.84"+0.77"+25.0%
Circumference72.70"77.53"+4.82"+6.6%
Revolutions per mile871.5817.3−54.2−6.2%

Speedometer difference

If your vehicle came with 195/40R17 and you fit 195/50R17, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.3 mph+1.3 mph
30 mph32.0 mph+2.0 mph
40 mph42.7 mph+2.7 mph
50 mph53.3 mph+3.3 mph
60 mph64.0 mph+4.0 mph
65 mph69.3 mph+4.3 mph
70 mph74.6 mph+4.6 mph
75 mph80.0 mph+5.0 mph
80 mph85.3 mph+5.3 mph

Each size on its own

Questions

Which is bigger, 195/40R17 or 195/50R17?
195/50R17 is taller by 1.54 inches (24.68" vs 23.14"). 195/40R17 is the same width.
Can I replace 195/40R17 with 195/50R17?
It is not recommended without checking carefully. The diameter difference is +6.6%, 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 195/50R17 change my speedometer?
When your speedometer reads 60 mph with 195/50R17 fitted (calibrated for 195/40R17), your real speed is 64.0 mph. Your odometer will under-count miles by about 6.6%.
Will 195/50R17 lift my vehicle?
Ride height changes by half the diameter difference: +0.77 inches of ground clearance at the axle.

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