Tire Size Box

225/25R21 vs 225/35R21

225/35R21 compared with 225/25R21

+7.0% diameter, 0.0" width

225/35R21 is 27.20" tall vs 25.43". More than the 3% rule of thumb, so check carefully before switching.

25.4"21" rim2.2"8.9" wide
225/25R21 (solid) compared with 225/35R21 (dashed outline), drawn to scale

With 225/35R21 tires, when your speedometer says 60 mph you are really going

64.2 mph

225/35R21 is +1.77 inches (+7.0%) in overall diameter. That is more than the 3% most shops and makers recommend.

225/25R21225/35R21Difference%
Overall diameter25.43"27.20"+1.77"+7.0%
Section width8.86"8.86"0.00"0.0%
Sidewall height2.21"3.10"+0.89"+40.0%
Circumference79.89"85.45"+5.57"+7.0%
Revolutions per mile793.1741.5−51.7−6.5%

Speedometer difference

If your vehicle came with 225/25R21 and you fit 225/35R21, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.4 mph+1.4 mph
30 mph32.1 mph+2.1 mph
40 mph42.8 mph+2.8 mph
50 mph53.5 mph+3.5 mph
60 mph64.2 mph+4.2 mph
65 mph69.5 mph+4.5 mph
70 mph74.9 mph+4.9 mph
75 mph80.2 mph+5.2 mph
80 mph85.6 mph+5.6 mph

Each size on its own

Questions

Which is bigger, 225/25R21 or 225/35R21?
225/35R21 is taller by 1.77 inches (27.20" vs 25.43"). 225/25R21 is the same width.
Can I replace 225/25R21 with 225/35R21?
It is not recommended without checking carefully. The diameter difference is +7.0%, 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 225/35R21 change my speedometer?
When your speedometer reads 60 mph with 225/35R21 fitted (calibrated for 225/25R21), your real speed is 64.2 mph. Your odometer will under-count miles by about 7.0%.
Will 225/35R21 lift my vehicle?
Ride height changes by half the diameter difference: +0.89 inches of ground clearance at the axle.

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