Tire Size Box

355/35R21 vs 245/45R22

245/45R22 compared with 355/35R21

−0.3% diameter, −4.3" width

245/45R22 is 30.68" tall vs 30.78". Within the 3% rule, so usually interchangeable.

30.8"21" rim4.9"14.0" wide
355/35R21 (solid) compared with 245/45R22 (dashed outline), drawn to scale

With 245/45R22 tires, when your speedometer says 60 mph you are really going

59.8 mph

245/45R22 is −0.10 inches (−0.3%) in overall diameter. That is within the 3% most shops and makers allow.

355/35R21245/45R22Difference%
Overall diameter30.78"30.68"−0.10"−0.3%
Section width13.98"9.65"−4.33"−31.0%
Sidewall height4.89"4.34"−0.55"−11.3%
Circumference96.71"96.39"−0.32"−0.3%
Revolutions per mile655.2657.3+2.2+0.3%

Speedometer difference

If your vehicle came with 355/35R21 and you fit 245/45R22, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph19.9 mph−0.1 mph
30 mph29.9 mph−0.1 mph
40 mph39.9 mph−0.1 mph
50 mph49.8 mph−0.2 mph
60 mph59.8 mph−0.2 mph
65 mph64.8 mph−0.2 mph
70 mph69.8 mph−0.2 mph
75 mph74.8 mph−0.2 mph
80 mph79.7 mph−0.3 mph

Each size on its own

Questions

Which is bigger, 355/35R21 or 245/45R22?
355/35R21 is taller by 0.10 inches (30.78" vs 30.68"). 355/35R21 is wider by 4.33 inches.
Can I replace 355/35R21 with 245/45R22?
Usually, yes. The diameter difference is −0.3%, inside the 3% rule of thumb most tire shops use. Check that the wider or taller tire clears your suspension and fenders, and that its load index meets your placard.
How much will 245/45R22 change my speedometer?
When your speedometer reads 60 mph with 245/45R22 fitted (calibrated for 355/35R21), your real speed is 59.8 mph. Your odometer will over-count miles by about 0.3%.
Will 245/45R22 lift my vehicle?
Ride height changes by half the diameter difference: −0.05 inches of ground clearance at the axle.

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