Tire Size Box

295/35R20 vs 295/45R20

295/45R20 compared with 295/35R20

+8.3% diameter, 0.0" width

295/45R20 is 30.45" tall vs 28.13". More than the 3% rule of thumb, so check carefully before switching.

28.1"20" rim4.1"11.6" wide
295/35R20 (solid) compared with 295/45R20 (dashed outline), drawn to scale

With 295/45R20 tires, when your speedometer says 60 mph you are really going

65.0 mph

295/45R20 is +2.32 inches (+8.3%) in overall diameter. That is more than the 3% most shops and makers recommend.

295/35R20295/45R20Difference%
Overall diameter28.13"30.45"+2.32"+8.3%
Section width11.61"11.61"0.00"0.0%
Sidewall height4.06"5.23"+1.16"+28.6%
Circumference88.37"95.67"+7.30"+8.3%
Revolutions per mile717.0662.3−54.7−7.6%

Speedometer difference

If your vehicle came with 295/35R20 and you fit 295/45R20, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.7 mph+1.7 mph
30 mph32.5 mph+2.5 mph
40 mph43.3 mph+3.3 mph
50 mph54.1 mph+4.1 mph
60 mph65.0 mph+5.0 mph
65 mph70.4 mph+5.4 mph
70 mph75.8 mph+5.8 mph
75 mph81.2 mph+6.2 mph
80 mph86.6 mph+6.6 mph

Each size on its own

Questions

Which is bigger, 295/35R20 or 295/45R20?
295/45R20 is taller by 2.32 inches (30.45" vs 28.13"). 295/35R20 is the same width.
Can I replace 295/35R20 with 295/45R20?
It is not recommended without checking carefully. The diameter difference is +8.3%, 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 295/45R20 change my speedometer?
When your speedometer reads 60 mph with 295/45R20 fitted (calibrated for 295/35R20), your real speed is 65.0 mph. Your odometer will under-count miles by about 8.3%.
Will 295/45R20 lift my vehicle?
Ride height changes by half the diameter difference: +1.16 inches of ground clearance at the axle.

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