Tire Size Box

215/35R20 vs 215/45R20

215/45R20 compared with 215/35R20

+6.5% diameter, 0.0" width

215/45R20 is 27.62" tall vs 25.93". More than the 3% rule of thumb, so check carefully before switching.

25.9"20" rim3.0"8.5" wide
215/35R20 (solid) compared with 215/45R20 (dashed outline), drawn to scale

With 215/45R20 tires, when your speedometer says 60 mph you are really going

63.9 mph

215/45R20 is +1.69 inches (+6.5%) in overall diameter. That is more than the 3% most shops and makers recommend.

215/35R20215/45R20Difference%
Overall diameter25.93"27.62"+1.69"+6.5%
Section width8.46"8.46"0.00"0.0%
Sidewall height2.96"3.81"+0.85"+28.6%
Circumference81.45"86.76"+5.32"+6.5%
Revolutions per mile777.9730.2−47.7−6.1%

Speedometer difference

If your vehicle came with 215/35R20 and you fit 215/45R20, 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 mph42.6 mph+2.6 mph
50 mph53.3 mph+3.3 mph
60 mph63.9 mph+3.9 mph
65 mph69.2 mph+4.2 mph
70 mph74.6 mph+4.6 mph
75 mph79.9 mph+4.9 mph
80 mph85.2 mph+5.2 mph

Each size on its own

Questions

Which is bigger, 215/35R20 or 215/45R20?
215/45R20 is taller by 1.69 inches (27.62" vs 25.93"). 215/35R20 is the same width.
Can I replace 215/35R20 with 215/45R20?
It is not recommended without checking carefully. The diameter difference is +6.5%, 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 215/45R20 change my speedometer?
When your speedometer reads 60 mph with 215/45R20 fitted (calibrated for 215/35R20), your real speed is 63.9 mph. Your odometer will under-count miles by about 6.5%.
Will 215/45R20 lift my vehicle?
Ride height changes by half the diameter difference: +0.85 inches of ground clearance at the axle.

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