Tire RulerWhat changes when you switch to 285/60R20
- Height: +0.46″ (+1.4%), so ground clearance at the axle goes up 0.23″.
- Width: −1.28″ (-32 mm). Check inner clearance to the suspension and frame, and the fender liner at full lock.
- Sidewall: +0.23″. A taller sidewall rides a bit softer and protects the wheel off-road.
- Revolutions per mile: 611 → 603. Your gears act about 1.4% taller; at 65 mph in a 0.69 top gear with 3.73s, that’s 1,704 → 1,680 RPM.
Sizes are theoretical, from the sidewall code. The same size can differ by a few tenths of an inch between brands and tread patterns; check the maker’s spec sheet for the exact model.
Other comparisons
Frequently asked questions
How much bigger is 285/60R20 than 33x12.50R20?
285/60R20 is 0.46 inches (1.4%) taller and 1.28 inches narrower: 33.5" × 11.2" versus 33.0" × 12.5".
Will 285/60R20 change my speedometer?
Yes, by 1.4%. Going from 33x12.50R20 to 285/60R20, an indicated 60 mph is about 60.8 mph.
Can I replace 33x12.50R20 with 285/60R20?
Often, yes: the height difference is within the ±3% most tire shops accept. Both fit a 20" wheel; confirm the rim width, load index and clearance for your vehicle.
Do I need to regear going from 33x12.50R20 to 285/60R20?
Usually not for a 1.4% change. With 3.73 gears, the 285/60R20 acts like 3.68.