Tire Size Box

295/30R21 vs 295/35R21

295/35R21 compared with 295/30R21

+4.2% diameter, 0.0" width

295/35R21 is 29.13" tall vs 27.97". More than the 3% rule of thumb, so check carefully before switching.

28.0"21" rim3.5"11.6" wide
295/30R21 (solid) compared with 295/35R21 (dashed outline), drawn to scale

With 295/35R21 tires, when your speedometer says 60 mph you are really going

62.5 mph

295/35R21 is +1.16 inches (+4.2%) in overall diameter. That is more than the 3% most shops and makers recommend.

295/30R21295/35R21Difference%
Overall diameter27.97"29.13"+1.16"+4.2%
Section width11.61"11.61"0.00"0.0%
Sidewall height3.48"4.06"+0.58"+16.7%
Circumference87.87"91.51"+3.65"+4.2%
Revolutions per mile721.1692.4−28.8−4.0%

Speedometer difference

If your vehicle came with 295/30R21 and you fit 295/35R21, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.8 mph+0.8 mph
30 mph31.2 mph+1.2 mph
40 mph41.7 mph+1.7 mph
50 mph52.1 mph+2.1 mph
60 mph62.5 mph+2.5 mph
65 mph67.7 mph+2.7 mph
70 mph72.9 mph+2.9 mph
75 mph78.1 mph+3.1 mph
80 mph83.3 mph+3.3 mph

Each size on its own

Questions

Which is bigger, 295/30R21 or 295/35R21?
295/35R21 is taller by 1.16 inches (29.13" vs 27.97"). 295/30R21 is the same width.
Can I replace 295/30R21 with 295/35R21?
It is not recommended without checking carefully. The diameter difference is +4.2%, 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 295/35R21 change my speedometer?
When your speedometer reads 60 mph with 295/35R21 fitted (calibrated for 295/30R21), your real speed is 62.5 mph. Your odometer will under-count miles by about 4.2%.
Will 295/35R21 lift my vehicle?
Ride height changes by half the diameter difference: +0.58 inches of ground clearance at the axle.

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