Tire Size Box

215/55R20 vs 215/65R20

215/65R20 compared with 215/55R20

+5.8% diameter, 0.0" width

215/65R20 is 31.00" tall vs 29.31". More than the 3% rule of thumb, so check carefully before switching.

29.3"20" rim4.7"8.5" wide
215/55R20 (solid) compared with 215/65R20 (dashed outline), drawn to scale

With 215/65R20 tires, when your speedometer says 60 mph you are really going

63.5 mph

215/65R20 is +1.69 inches (+5.8%) in overall diameter. That is more than the 3% most shops and makers recommend.

215/55R20215/65R20Difference%
Overall diameter29.31"31.00"+1.69"+5.8%
Section width8.46"8.46"0.00"0.0%
Sidewall height4.66"5.50"+0.85"+18.2%
Circumference92.08"97.40"+5.32"+5.8%
Revolutions per mile688.1650.5−37.6−5.5%

Speedometer difference

If your vehicle came with 215/55R20 and you fit 215/65R20, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.2 mph+1.2 mph
30 mph31.7 mph+1.7 mph
40 mph42.3 mph+2.3 mph
50 mph52.9 mph+2.9 mph
60 mph63.5 mph+3.5 mph
65 mph68.8 mph+3.8 mph
70 mph74.0 mph+4.0 mph
75 mph79.3 mph+4.3 mph
80 mph84.6 mph+4.6 mph

Each size on its own

Questions

Which is bigger, 215/55R20 or 215/65R20?
215/65R20 is taller by 1.69 inches (31.00" vs 29.31"). 215/55R20 is the same width.
Can I replace 215/55R20 with 215/65R20?
It is not recommended without checking carefully. The diameter difference is +5.8%, 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 215/65R20 change my speedometer?
When your speedometer reads 60 mph with 215/65R20 fitted (calibrated for 215/55R20), your real speed is 63.5 mph. Your odometer will under-count miles by about 5.8%.
Will 215/65R20 lift my vehicle?
Ride height changes by half the diameter difference: +0.85 inches of ground clearance at the axle.

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