Tire size
285/35 R20
Full dimensions and a live comparison calculator for the 285/35 R20 tire size.
Overall diameter
707.5 mm
27.85″
Sidewall height
99.8 mm
Circumference
2.223 m
Revs / km
449.9
Section width
285 mm
Aspect ratio
35%
Rim diameter
20″
508.0 mm
Radius
353.8 mm
What does 285/35 R20 mean?
The 285 is the section width in millimetres, measured sidewall to sidewall. The 35 is the aspect ratio — sidewall height as a percentage of width, so the sidewall here is 99.8 mm. The R20 means a radial-construction tire designed for a 20-inch wheel rim. Together these give an overall diameter of 708 mm.
Compare 285/35 R20 with another size
Current Tire
New Tire
Ground line · scaled comparison
Not Recommended
Over 5% — speedometer & ABS may misread
Diameter change
-73.2 mm
-10.35%
Speedometer at 100
89.7 km/h
-10.35% error
Ground clearance
-36.6 mm
ride height delta
Sidewall change
+1.5 mm
revs/km: 501.8
Permalink for this comparison:
/compare/285-35-r20-vs-225-45-r17Common alternatives to 285/35 R20
These sizes are within a few percent overall diameter — usually safe on the same vehicle from a speedometer-error standpoint.
Compare 285/35 R20 with popular upgrades
Plus-size upgrades from 285/35 R20
Fitment safety note
Overall diameter, speedometer error and circumference are only part of the picture. Physical clearance, wheel offset (ET), hub bore, suspension geometry, load index and your manufacturer's recommendation all decide whether a size is truly safe on your car. Always cross-check with the vehicle manual or a qualified fitter before changing tire size.