ElpiAuto

Tire size comparison

275/65R20 vs 325/60R20

325/60R20 is 1.28″ (33 mm) taller than 275/65R20, a 3.8% difference in overall diameter — outside the ±3% band, so expect the speedometer to drift and check for rubbing before fitting.

34.07″35.35″A  275/65R20B  325/60R20Both sizes to scale · dimension lines in inches
Measurement275/65R20325/60R20Difference%
Overall diameter34.07″35.35″+1.28″+3.8%
Section width10.83″12.80″+1.97″+18.2%
Sidewall height7.04″7.68″+0.64″+9.1%
Circumference107.05″111.07″+4.02″+3.8%
Revs per mile591.9570.5−21.4−3.6%
Revs per km367.8354.5−13.3−3.6%

Speedometer: with 275/65R20 as the original, 325/60R20 makes an indicated 60 mph really about 62.3 mph, and the axle sits ~0.64″ higher.

Reading this comparison

The overall diameter is what matters here: 325/60R20 is the taller tire. It sets ride height, gearing and how far the tire travels per revolution — which is what the speedometer and odometer count. Width and sidewall change fit and feel (a wider tire needs a wider wheel and more clearance; a shorter sidewall sharpens steering) but not the gearing.

Figures are geometric estimates from the size codes; real moulded tires vary by brand by 1–3%. Confirm load rating, wheel width and physical clearance on your vehicle before fitting. To compare any other two sizes, use the tire size comparison tool; to decode one size and see what else fits its wheel, the tire size calculator.

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